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April 2020

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In This Issue - (INDEX)


Fiber Optics & Training In The Time Of Pandemic
Now Is The Time To Learn
Enlarging The FOA Knowledge Base
Coherent Communications
Worth Reading - The Internet Is Working! Burning Cell Towers.
Reader Photo
Fiber Optic Cable Plant - The Finished Product
Hollow Core Fiber
"AntiDust" Dust Caps?
Innovative Microscope Awarded Patent
Bend Radius Tutorial
Standard For Installation
Recognizing The FOA Founders
Worth Reading- News Summary
Video Microscope for Fast MPO Inspection
10GPON Update
Lennie's Guide - 25th Anniversary Edition
FOA Guide Updates
FOA School Offers Toolkit With Online Training

FOA Certifications: 

CFOT Total


FOA Facts - about the organization

FOA Resources  
Fiber U - free online self-study courses
Publications: FOA Textbooks, NECA/FOA 301
 "Quickstart Guides"
 videos FOA YouTube Videos
Online Reference Guide: Many new pages
Certification. Updated:  FOA OSP Certification
FOA Schools: New schools and programs
Q&A: What technical questions you asked the FOA?
FOA Fiber FAQs Page
Product News - New stuff
Worth Reading: News from around the world

DIG SAFE - Call 811 before you dig!

See FOA Jobs Web Page and FOA on FOA on LinkedIn
The FOA Jobs Web Page has been updated and a new page added on Using your FOA Training/Certification to Find the Right Job in Fiber Optics

Where Are The Jobs In Fiber Optics? FOA talks about all the applications for fiber optics, what jobs involve and the qualifications for the workers in the field in this YouTube video.

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CFOT Renewals
Renew your FOA certification online - plus get a discount on the new FOA books and an extra month free. Details here.

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Current Issue of FOA Newsletter

The FOA CFOT® (Certified Fiber Optic Technician) and Fiber U® (the FOA online self-study program) are registered trademarks of the FOA.
FOA Guide
Want to know more about fiber optics? Study for FOA certifications? Free Self-Study Programs are on "Fiber U®." Looking for specific information? Here's the largest technical reference on the web: The FOA Online Fiber Optic Reference Guide.

Free online self-study programs on many fiber optics and cabling topics are available at Fiber U, FOA's online web-based training website.

 FOA Reference Books
Available Printed or eBooks
The fiber book is available in Spanish and French

FOA Reference Guide to Fiber Optics book FOA Reference Guide to Premises Cablng book FOA Reference Guide to OSP Fiber Optics book FOA Reference Guide to Fiber Optics book
FOA Reference Guide to Fiber Optic Network Design book FOA Book on Fiber Optic Testing FOA Outside Plant Fiber Optics Construction Guide  Lennie Lightwave

Lennie and Uncle Ted's Guides are now also available as free iBooks on iTunes.
Lennie Lightwave's Guide To Fiber Optics   Uncle Ted's Guide to Premises Cablling
Click on any of the books to learn more.
Fiber Optic Safety Poster to download and print

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The FOA Newsletter is edited by Jim Hayes - send your stories, leads, ideas, comments to <jim @>
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FOA Newsletter - Features

Fiber Optics And Training In The Time of Pandemic

With most of the world still sequestered at home, many continuing to work using the Internet and phones,  we have learned that the work we all have done in building the world's fiber optics networks has created an amazingly effective communications network. If there was ever a stress test for these networks, it is now, with the explosion of WFH (work from home - you know techies would create a TLA - three letter acronym - for it!), online education, watching video and even using video conferencing to keep families connected.

We should pat ourselves on the back - we all do great work!

But the current situation has also pointed out the weaknesses of online life. Too many people are unserved or underserved, not having connections and/or devices to connect to the Internet. Some schools trying to convert classrooms to online study found half their students were unable to participate. Rural areas are a known weakness of broadband coverage, but today we also realize that many living in the cities are also not connected and/or do not have devices to use. For the service providers it is a matter of economics; rural areas are expensive to connect and the inner city often cannot afford the services.

What if we had a similar attitude about roads? Or electricity? Have we not learned that connectivity is just as important today as they are? After the world starts returning to normal, we need to remember what we have learned now - and make efforts to solve these problems. 

Worth Reading: Post-Pandemic, Here’s How America Rises Again
Thomas L. Friedman, NYTimes Opinion
Hopefully, when Congress gets done allocating several trillion dollars simply to keep the economy afloat, we will be able to have another discussion: What should we invest in so we don’t just burden young Americans with a mountain of new debt, but also arm them with the tools to grow out of it and still prosper in the 21st century?

Expanded high-speed internet connectivity everywhere, but particularly in rural America, so more people can participate in the innovation economy.

“Building fiber infrastructure all across heartland America ensures that high-paying jobs can take place anywhere,” explained Matt Dunne, executive director of the Center on Rural Innovation, and it makes the whole country “more resilient to future pandemics and climate change-related weather events that require children and workers to stay home.”

But, it isn't as easy as you think.

Worth Reading: Microsoft Airband: An annual update on connecting rural America
Mar 5, 2020
From the article: "In the summer of 2017, we launched the Microsoft Airband Initiative, which brings broadband connectivity to people living in underserved rural areas. ... At two and a half years since launch, we are at the halfway point of the time we gave ourselves to meet this goal and we feel good about the steady progress we’ve made and how much we have learned. But one thing we have learned is that the problem is even bigger than we imagined."

What Is Happening Now With Installations?
FOA has had discussions with people around the world and some construction projects have been put on hold but many others continue often at a fast pace. Michael Wood at Clearfield, a major supplier of fiber optic equipment and a FOA approved school told us, "We are having record day after record day because the providers are trying to get as many underserved up and running as they can! Sucks that it takes an emergency, but at least its building broadband infrastructure."

Once restrictions are lifted, we expect to see a flood of projects everywhere. Then we will have a deficit of trained and certified techs to do the work. Below is how the FOA is working on that problem.

Now Is The Time To Learn

FOA has been using this time productively. We've been updating technical pages, adding Fiber U programs and working with our schools on blended learning to allow them to help students learn and prepare for certification.

While practically all regular in-person classes of all kinds are cancelled, learning does not need to stop. Most schools and colleges have moved classes online. FOA has offered free online classes at
Fiber U for more than two decades now, and many of the FOA approved training organizations already are using Fiber U as preparation for regular classes, allowing them to focus on hands-on activities when students show up for class.

Blended Learning
While most FOA schools have suspended in-person training during this period, some are offering a "blended learning" option. That means that students sign up for a FOA certification course, take the classroom sessions on Fiber U with the assistance of a FOA certified instructor. Now online instruction can include reviewing the labs using the
Fiber U Basic Skills Labs, then when it's possible to attend classes at the school, complete the hands-on labs and take the FOA certification exam. Alternatively, some schools are experimenting with "remote labs," where the students get tools and labs are conducted by videoconferencing. Contact the FOA for more information.

OJT - On-The-Job-Training
Many novices get a job and learn on the job. They usually have an experienced tech who helps them gain the knowledge and  learn the skills they need to perform their job. Thinking about this in relation to the 
FOA KSAs, the knowledge, skills and abilities needed by a fiber optic tech,  the tech will learn skills but not the basic knowledge that helps them understand the processes involved. FOA can offer help here, using our Fiber U online sefl-study programs. While the tech learns on the job, they become a Fiber U trainee, getting the knowledge they need, while working under their "mentor" at work. This is particularly good for contracting companies who need techs but do not have the usual training courses available. Interested in OJT programs? Contact FOA for more information.

Enlarging The FOA Knowledge Base

Here are some projects we've completed recently to enhance the FOA knowledge base and provide learning opportunities for you:

Fiber U Basic Skills Labs - Fiber Optics And Premises Cabling
Fiber U has been offering courses on fiber optics and premises cabling that cover the knowledge part of the FOA KSAs, but the assumption was you needed a hands-on lab at a FOA approved school or OJT - on the job training - to develop the skills - the "S" of the KSAs.

The idea of the Fiber U Basic Skills Labs is that if you have the equipment you can learn at your location with an instructor/tutor online or on your own by following these instructional aids. T
he "Basic Skills Lab" online courses provide the training materials developed by instructors to help students learn in their hands-on labs, including workbooks, lists of tools, and VHOs - virtual hands-on - step-by-step instructions to follow when doing training exercises.

Recently, we have updated the materials in the Fiber Optics Basic Skills Labs which includes cable preparation, splicing, termination and testing. And we have created a Basic Skills Labs - Copper Premises Cabling to cover UTP (Cat 5) and coax copper cable processes. As with all Fiber U courses, these are free. The Premises Copper Cabling Basic Skills Lab  has a lab workbook, VHOs on each topic and quizzes to allow you to check your knowledge. Like the fiber optic course, if you have access to tools, you can do all the processes at your own location.

Coherent Communications  - FOA Guide

As long haul systems move up from the current standard of 100Gb/s, a decade-old technology, coherent communications, has become the standard for link transmission. Coherent communications systems are complex and expensive compared to the direct modulation systems of the past, but minimize the problems of fiber dispersion that has been a problem in the past while still being compatible with DWDM and fiber amplification.
coherent fiber optic link
To see the different in complexity, here are a coherent fiber optic transmitter (L) and receiver (R) compared to a direct modulation transceiver

Learn about Coherent Communications Systems in the FOA Guide.

There's More
While you are sequestered at home, we've provided some interesting things to read in this newsletter and many other places around the Internet in "Worth Reading" below. We've also got other good, free online training at Fiber U, including the
Fiber Optics Basic Skills Labs, Basic Skills Labs - Copper Premises Cabling described above. We also have the OSP Construction course and a bunch of courses on applications like Data Centers or Fiber for Wireless. If you are preparing for an FOA certification course, now is time to take the Fiber U courses linked to FOA certifications.

Just be safe and stay healthy!

Worth Reading

Sometimes we forget about the network we're all building, so it's interesting to read an article about the Internet, especially now we our dependence on it has become so great.

Your Internet is working. Thank these Cold War-era pioneers who designed it to handle almost anything

Washington Post
Coronavirus may have forced people to stay at home, but the Internet these scientists envisioned long ago is keeping the world connected

Most Insane Article During the Current Crisis:

Burning Cell Towers, Out of Baseless Fear They Spread the Virus

A conspiracy theory linking the spread of the coronavirus to 5G wireless technology has spurred more than 100 incidents this month, British officials said.

Read more from the NY Times.

And here from The Sun in the UK. Good photos - dont miss the comments too.

Best Reader Photo Of The Month

tree trimming

Posted on the FOA Facebook page, this is not the result of a storm, it is the aftermath of tree trimming.

SPECIAL OFFER - Save 1/3 On Your Certification Renewal Cost

In the near future, there will be a requirement for continuing education to renew your FOA certifications. We'll explain why soon, but for now FOA is testing an option for renewals where you take a short Fiber U online self-study course with certificate of completion exam and pay for renewal when taking the exam. 

If you would like to help FOA test this option, you can save 1/3 the cost of your renewal.  Go here to take the Fiber U CFOT Renewal Course:

Looking For A Job?

Did you know that FOA has a lot of information on the website about where the jobs are in fiber optics and how to get one of them? One of the topics is how to use job search sites to find fiber optic jobs. We just added a new site to the link, ZIPRECRUITER.COM, that you should check out. They even have some good information on what fiber optic jobs pay, based on their listings.

There's more below....and More "Worth Reading" Below

.. plus some really interesting technical questions discussed in depth

The FOA Update Page covers all the new technology and applications we covered in this newsletter in 2018-19. Now you can review all that new tech at once.

The FOA Fiber FAQs Page (FAQs = frequently asked questions) gathers up questions readers have asked us (which first ran in this newsletter) and adds tech topics of general interest.

This months "Good Questions" has some unique questions from our readers.

Fiber Optic Cable Plant - The Finished Product

This month, FOA has received inquiries from several sources that all deal with the same subject - what is involved in the specification and acceptance of a cable plant at the end of a installation project. And what are reasonable specifications for a cable plant.

FOA has a lot of documentation on a project involving  designing and installing a cable plant in the FOA Online Guide and our Textbooks, but the acceptance process is relegated to a few paragraphs. Let's look at a project and include a few links to FOA tech documents in case you want to investigate further.

The Project "Deliverables"
Fiber optic projects start with a design that creates project paperwork - the scope of work (SOW), request for proposal or quote (RFP/Q) and a contract with the builder/installer. A "Scope of Work" document is created by the initiator of a project to describe the work to be performed or the services to be provided by a contractor. It describes tasks to be performed, directs methods to be used, and defines the period of performance. It should contain design and performance requirements. A scope of work for communications cabling or fiber optics may be part of a larger building project document that is based on a standardized format called "MasterFormat" in the US and Canada.

A well written scope of work can do more for the success of a contract than any other part of the contracting process. A good scope of work is clear, complete, and logical enough to be understood by the respondent and the university personnel who will administer it. Because it describes the details of performance, it is the yardstick against which the respondent's performance is measured. That is why the user's requester, contract administrator and/or subject matter expert should be the focal point for developing the scope of work.

What we are discussing here is the final product - the "deliverables" - that define the final product that the end user expects to have when the installation is complete and ready to use, or in some cases already has the communications equipment installed and operating. Of course the deliverables include the physical cable plant, but also must include full documentation and test results, and maybe even a warranty.

Cable Plant Specifications
What are reasonable specifications for a cable plant. We've often heard stories of specs that are too stringent and others too lax. Since specifications for the installed cable plant are up to the person specifying the cable plant, they may be confusing because very few standards exist for the design and specification of the cable plant. OSP networks have traditionally been specified and owned by sophisticated users who have a history of what specs can be expected. Premises cabling systems tend to use component specs from TIA or ISO/IEC standards that are generally too lax, much higher than what should be expected.

Let's do the executive summary. The cable plant should be specified for loss using a loss budget. Network speed may dictate specifications for component types or bandwidth. Here is a summary of FOA's "reasonable specs" to use for cable plant loss budgets. Below we'll get into testing with loss budgets based on those specs.

Fiber: G.652 attenuation 0.4dB/km at 1310nm, 0.25dB/km @ 1550nm
Splices: Average 0.1dB, reject @ 0.2dB
Average loss 0.3dB, reject @ 0.5dB, Reflectance better than -40dB.
Long haul fibers like G.654 will have slightly better attenuation specs, ~0.2dB/km.

Fiber: Multimode OM3/OM4 attenuation 3dB/km @ 850nm, Bend insensitive fibers
Singlemode OS1/OS2 attenuation 0.5dB/km @ 1310nm, Bend insensitive fibers
Splices: Average 0.3dB, rare in premises
Average loss 0.5dB, SM reflectance better than

Cables, of course, are specified according to the requirements of the project and it's physical locations.

The final documentation delivered to the customer must be comprehensive, with full route information including GIS (geographic information system) data on the location of the cable and every component - cables, manholes/handholes, splice locations and full descriptions, plus test data. The physical component and location information is obvious, but what is not is test data, which we elaborate on below.

What's sometimes missing, based on inquiries we get from end users, is understandable documentation. Managers who may not be familiar with fiber optics can be given reams of documentation which they are expected to use to sign off on a project. There are many stories about problems at this stage: signing off on a data center installation where all 4,000 connectors were failures, getting test data on a OSP network where every OTDR test was the same, you get the idea. Before signing off on a project, someone who knows fiber optics and was involved in the project should review the documentation and test data and verify that it is correct and valid.

Cable Plant Test Data
To prove the cable plant was installed properly requires test data, of course. During the design phase, loss budgets calculated for each cable run should provide an estimate of the expected loss of the fibers in each cable link to compare to actual test results.

Short fiber optic premises cabling networks are generally tested in three ways, connector inspection/cleaning with a microscope, insertion loss testing with a light source and power meter or optical loss test set, and polarity data, meaning that the routing of fibers is confirmed so that when connecting equipment the tech can identify fiber pairs for transmit and receive. Polarity testing generally can be done with a visual fault locator to confirm that fibers are connected per the documented cable diagrams.

Outside plant (OSP) testing is more complex. If the cable plant includes cables concatenated with splices, it's expected to add OTDR testing to the connector inspection, insertion loss and polarity testing. If the link has passive devices like FTTH splitters or WDMs, those need to be tested and documented also.

There is one thing that whoever is reviewing the data - and going back to the design phase, whoever writes the test specifications based on the loss budgets in the first place - needs to understand: none of these are absolute numbers. The loss budget which is created early in the design phase estimates the loss of the cable plant based on estimates of component loss and therefore is not an absolute number, but an estimate to be used to compare to test data.

Test data is created by instruments and related components that make measurements which have  measurement errors. There are always factors in making measurements that cause the instrument reading to be inaccurate - only an approximation of the real value - and the real value is unknowable because of measurement errors. (If you are curious, look up the Heisenberg uncertainty principle.)

Let's look at this symbolically:


The loss budget is not exact, nor is the testing, so there is a range of measurements that should be acceptable. Some judgement is needed to determine if a particular fiber is acceptable.

In our experience, those two factors cause more stress between managers and installers than just about any other factor in a
cable plant project. Consider these examples of the issues with loss budgets and testing errors.

OSP Cable Plant
Here is the situation a CFOT found themselves in when they called the FOA. They were an 30+ year experienced splicer with a half-million splices of experience. A customer wanted to specify a long cable plant (~50 miles/80km) with splices that averaged 0.05dB and any splices above 0.15dB was not acceptable. Testing of the splice loss would be done with an OTDR with bidirectional measurements and averaged.

What made this call particularly interesting is this tech had some real world data, the kind you do not see often. On a past job, he had spliced a ~60 mile (100km) 288 fiber cable plant at 18 splice locations, that's 5,184 splices. His test records showed that 60% of the splices were in the range of 0.02 to 0.08dB and 40% were in the range of 0.08 to 0.15dB. Only 17 splices were over 0.15dB.

OSP cable plant

The customer noted that the manufacturer of the splicer used by the tech quoted a splice loss capability of 0.02dB, so a field spec of 2.5 times that should be easily achievable in the field. What the customer did not understand was that 0.02dB spec for the splicer was data taken in a laboratory on a new or perfectly set up machine. The splices were made by breaking a fiber and splicing it back together. Every splice used in determining the splicer capability used identical fibers - they were the same fiber.

In the field, when splicing cables together, the environment is not like a lab. Machines are used to splice thousands of fibers. The fibers in the cable can be from numerous production runs and will have variations in mode field diameter (MFD) and geometry. Assuming a long haul network like this one is using G.654 fiber, we can look at the ITU standard for G.654 fibers and we find these specifications:

Mode Field Diameter: 9.5-10.5microns
Core Concentricity Errors: 0.8micron

That variation in fiber geometry and MFD can produce a real difference in splice loss that will be directional. That difference can be 0.05 to 0.1dB. That is independent of how well the splicer can align and fuse fibers. Even if aligned
perfectly and spliced perfectly the differences in the fiber will cause directional splice differences - higher in one direction, lower in the other.

The can be a 0.20 to 0.25dB difference in directional splice loss when measured by an OTDR 
caused by MFD variation in the fibers (data from Corning ap note AN3060). This is something which many techs are familiar with, but that method of bi-directional testing merely removes the OTDR scattering error and gives the average of loss from each direction. It can't compensate for the actual directional splice loss caused by the difference in MFD. Let's repeat that: Bi-directional OTDR testing removes the OTDR error caused by differences in fiber MFD or backscattering, but cannot compensate for the actual directional difference in splice loss caused by the difference in MFD.

Back to the customer's spec. They wanted an average splice loss of 0.05dB and no splices over 0.15dB - which was unacceptable. Using some math, we can analyze the data the tech had from the prior 60 mile (100km) job. The average splice loss on that cable plant was ~0.07dB. And only 17 were larger than 0.15dB, so the reject rate would have been 0.3%.

If we compare the results of that job to the specs the customer wants on the new job, the difference would be 0.02dB/splice at 18 splice points. The total loss difference in the
60 mile (100km) cable plant would be 0.02dB X 18 or 0.36dB - and that is on a 60 mile (100km) run where the fiber loss is 0.20dB/km X 100km or 20dB. And the loss of the original 18 splices was only ~1.33dB! The difference is negligible and the measurement uncertainty of the OTDR test of end-to-end loss is much bigger than the difference.

Premises Network
In premises fiber optic networks, the TIA standards allow for connections to have a loss of 0.75dB - that is two connectors mated to create a connection.
A fiber optic connector has no loss, per se, because it is not being used. When in use, it is mated to another connector creating a joint between two fibers, and that joint is what has loss - a "connection" loss.

That number has been in the standards for at least 30 years, but even then typical connectors with ceramic ferrules were much better than that. That 0.75 dB loss was needed for early connectors like SMAs and Biconics, so it became the standard, Later, although everyone knew that the typical ST, SC, FC and then LC connector was much better, the industry saw the introduction of array connectors (MPOs) where the 0.75 dB loss was needed, so rather than have different values for single fiber and array connectors, it was left at 0.75dB.

premises cable plant

If you do a loss budget for a premises network with an intermediate patch panel like the one above, your loss budget would include 4 connection losses, the two in the patch panel and the ones in the outlets at each end where you connect the patchcords to the LAN gear. The 4 connection losses using the TIA model would allow a loss budget for connections of 4 X 0.75dB = 3.0dB. But if typical
connections are less than 0.5dB, you could have 3 connections at 0.5dB and 1 connections could be 1.5dB. If you had good connections of 0.3dB, that fourth connection could be 2.1dB!

When we look at fiber losses, TIA allows f
iber losses of 3.0 to 3.5dB/km at 850nm for multimode fiber. Actual fiber is now less than 3dB/km, but since links are typically short, ~100meters, the error due to fiber being better than the standard is only tenths of a dB. That is too small to matter. 

If our link above is 100m, the loss budget using TIA numbers would be:

Fiber 0.1km X 3.0dB/km = 0.3dB
Connectors 4x 0.75dB = 3.0dB
Link Loss Budget = 3.3dB

With more realistic numbers, say 0.5dB connections, it would be:

Fiber 0.1km X 3.0dB/km = 0.3dB
Connectors 4x 0.5dB = 2.0dB
Link Loss Budget = 2.3dB

And with really good
connections, say 0.2dB:

Fiber 0.1km X 3.0dB/km = 0.3dB
Connectors 4x 0.2dB = 0.8dB
Link Loss Budget = 1.1dB

That's a 2.2dB difference in a 100m multimode network; that's a big uncertainty! What would we choose for a GO/NO-GO loss? Our judgement would be the link should be under 2.3dB

Now what happens when we test this link?

We use a LED test source at ~850nm, a meter calibrated at 850nm reading in dB, and two reference cables to make a double-ended test. In a short link like this the cause of measurement uncertainty is the loss of the connections. Variations in modal fill from the test source and launch cable can result in 0.2dB variations, which has resulted in an international standard for mode fill, called "encircled flux" which most multimode test sources today meet, but early sources are unknowns and add to the uncertainty, The launch and receive cables also add to the uncertainty, since fiber standards allow up to +/-5% variation in core size, which can cause loss variations at connections depending on the direction of the light.

There are so many variables in making an insertion loss test of multimode fiber that they fill a giant table in the FOA page on "metrology" or the science of fiber optic measurements. The generally accepted number for uncertainty of this kind of measurement is ~0.2 to 0.5dB.

So exactly what is a acceptable test result for this fiber link? If we measure a loss of 1.5dB, no question it passes. If it measures 3.5dB, that's certainly a problem. But what if it measures 2.5dB? That's 0.2dB higher than the loss budget estimate we used, but we know the measurement is uncertain by +/-
0.2 to 0.5dB, and 2.3dB is within the uncertainty of the measurement. It's probably OK.

Why Would You Want A "Hollow Core" Fiber?

OFS hollow core fiber
OFS Hollow Core Fiber Preform

OFS has just introduced AccuCore HCF Optical Fiber Cable, the world's first terrestrial hollow-core fiber (HCF) cable solution.


Fiber optics is often described as "sending signals at the speed of light." But typical fibers are made of glass with an index of refraction of ~1.5, so light travels at the speed of light in a vacuum, c, divided by the index of refraction of the medium it is traveling in, here 1.5, or c/1.5 = 0.67c - 2/3 the speed of light in a vacuum. That's about the same speed as electrons travel in twisted pair cables and much slower than in coax cables where the speed approaches 0.9c.

So why hollow core fibers? Latency.

Light travels about 50% faster in a hollow core compared to a solid silica core of conventional optical fiber. Consequently, light transmitted in a hollow-core fiber arrives 1.54 microseconds faster for each kilometer traveled compared with conventional optical fiber.

The AccuCore HCF Optical Fiber Cable solution is based on proven hollow-core fiber technology and includes indoor/outdoor cable and termination with standard connectors, which are fusion spliced to the patented photonic bandgap hollow-core fiber. OFS also offers installation services and both passive and active component selection to meet customer requirements. AccuCore HCF optical  fiber cable has been successfully deployed, carrying live traffic in several networks. Read the press release here.

Applications include:

High-frequency trading
High-performance computing
5G X-haul mobile networks
Intra-data center interconnection

Read more.

When Is A Dust Cap Not Filled With Dust?

When it's a "CleanAdvantage(tm)" cap on a Corning Edge(tm) factory terminated cabling system.


Corning understands the value of clean connectors to ensure optical performance. So much so that we have developed a new factory cleaning and sealing process, Corning® CleanAdvantage™ technology, to ensure a pristine end face upon first use for all our EDGE™and EDGE8® solutions. Thus, saving you as the installer time and money during the initial installation. So go ahead and uncap that CleanAdvantage connector so that you can connect with confidence."

Read More.

Don't miss this Corning trivia about fiber - 3 times stronger than steel.

Innovative Microscope Awarded US Patent

Ed Forrest of Fiber Optic Precision Cleaning has been granted US Patent No. 10578847 for his innovative widefield microscope for fiber optic connector inspection. Unlike other fiber optic microscopes that closely inspect the end of the connector ferrule, this microscope looks at the whole ferrule and the receptacle to determine what else is dirty besides the end of the ferrule. Dirt in the connector body is often the source of the dirt on the end of the ferrrule, so it needs cleaning also. This microscope should, of course, be used in conjunction with a normal 100-400X inspection microscope.

EF Scope

Fiber Optic Precision Cleaning also offers several excellent books, whitepapers training on fiber optic connector inspection and cleaning.

Is There A Standard For Fiber Optic Installation?

Another question we get often is "Is there a standard for fiber optic installation." The answer is yes, but not from the usual standards groups you might think about. Over 20 years ago, the National Electrical Contractors Association (NECA) asked FOA to help create a standard for installation. That standard, ANSI/NECA/FOA-301 has been updated three times already and is about ready for another update.

Unlike most of those groups who charge you a fortune for standards, FOA covers the cost so
ANSI/NECA/FOA-301 is available free from FOA.

NECA/FOA 301 Fiber Optic Installation Standard

Download your free copy of
ANSI/NECA/FOA-301 here (PDF)

More Questions and Answers from our readers below.

Safety Leader Magazine

Safety Leader Magazine

Safety Leader, a new quarterly magazine, informs and educates electrical contractors on safety from various angles—electrical, workplace, PPE, regulations, leadership, line work, NFPA 70E, and more. Safety Leader is bundled with ELECTRICAL CONTRACTOR in February, May, August and November. To receive Safety Leader subscribe to ELECTRICAL CONTRACTOR magazine here or subscribe to the ELECTRICAL CONTRACTOR newsletter here.

Conference On Damage Prevention Cancelled But Goes Online

CGS 2021 Tampa

CGA 811 Excavation Safety Conference & Expo, the premiere international event in the damage prevention industry, was supposed to be March 24-26 but was cancelled due to the coronovirus. Next year's program will be in Tampa.

FOA was supposed to participate with a talk about New Installation Techniques For Fiber Optics and participate in a panel with members of the North American Telecom Damage Prevention Council to discuss the issue of protection fiber infrastructure from damage.

The conference organizers are having a several "Digital Days of Education" so hopefully you can soon watch the sessions online.


The magazine, dp-Pro, sponsor of the conference, has also published it's latest issue with an article by FOA on "New Construction Techniques in Fiber Optics" and a overview of the FOA. You can read the magazine here.

Bend Radius (Quick Tutorial)

All fiber optic cables have specifications that must not be exceeded during installation to prevent irreparable damage to the cable. This includes pulling tension, minimum bend radius and crush loads. Installers must understand these specifications and know how to pull cables without damaging them.

The normal recommendation for fiber optic cable bend radius is the minimum bend radius under tension during pulling is 20 times the diameter of the cable. When not under tension, the minimum recommended long term bend radius is 10 times the cable diameter.

Note: Always check the cable specifications for cables you are installing as some cables such as the high fiber count cables have different bend radius specifications from regular cables!

Fiber Optic Cable Bend Radius
Under tension (top) and after pulling (bottom)

Bend radius example: A cable 13mm (0.5") diameter would have a minimum bend radius under tension of 20 X 13mm = 260mm (20 x 0.5" = 10") That means if you are pulling this cable over a pulley, that pulley should have a minimum radius of 260mm/10" or a diameter of 520mm/20" - don't get radius and diameter mixed up!

Why is it important? Not following bend radius guidelines can lead to cable damage. If the cable is damaged in installation, the manufacturer's warranty is voided. Here is what one manufacturer's warranty says: "This warranty does not apply to normal wear and tear or damage caused by negligence, lack
of maintenance, accident, abnormal operation, improper installation or service, unauthorized repair, fire, floods, and acts of God.
" And their specifications call our the minimum bend radius as "20 X OD-Installation, 10 X OD-In-Service."

Some FOA Founders Still Active

Recognize Anybody Here? This is the FOA Board of Advisors 20 years ago, meeting to work on FOA certifications.

Those listed below in BOLD are still active teaching and working with FOA.

FOA Directors 1999

Who Were The FOA Founders?

Jim Hayes, President of FOTEC Inc. Pioneering fiber optic entrepreneur in test equipment and trainer who was trained in physics/astronomy. Author of many EIA/TIA standards and the instigator of the NBS/NIST fiber optic calibration program. Creator of the Fiber U training conferences. Author of ten textbooks, hundreds of technical articles. Current FOA President.

Eric Pearson, Pearson Technologies. Trained by Corning in the 1970s, considered an industry expert on termination and splicing, training since the early 1980s. Active FOA Instructor.

Dominick Tambone, Engineer, Automatic Tool and Connector, fiber optic termination and installation, training since the early 1980s. Contractor and
Active FOA Instructor.

Bill Graham, Mississauga Training Associates, Toronto, ON, CN. Background in utilities, military, metropolitan fiber optics, training since the early 1990s. Current FOA Director.

Prof. Elias Awad, Wentworth Institute, Boston, MA. Started one of the first fiber optic academic programs in the engineering department in late 1980s. Creator of NSF program “Fiber Optics For Engineering Technology” (NSF#9353997).

Prof. John Highhouse, Lincoln Trail College, Robinson, IL. Head of telecom training program, started teaching fiber optic outside plant construction in late 1980s. Masters in Education, specialty testing.

Paul Rosenberg, writer and technical trainer
Dan Silver, Product Specialist, 3M Fiber Optics, trainer and applications. The man with the idea to create the Fiber U training conferences and active FOA member.

Eric Loytty, Field Engineering, Corning/Siecor, applications and training.

Bob Mason, Product Manager, Network Systems, Panduit, applications and training.

Doug Elliott, IBEW Instructor, Toronto, ON, CN. One of first IBEW apprenticeship instructors to teach fiber optics.

Tom Collins, Northern Kentucky Technical College, Professor. Techtricians, Owner/instructor. Current FOA Director.

Dan Lyall, Project Engineer, Lockheed Martin, applications and training.

James H. (Jim) Davis, Program Director, Navsea 56ZC, Navy fiber optic standards.

Dave Chaney, Disney, Network Manager

Tony Beam, Tyco/AMP, Product Manager 

Richard J. Smith, FOTechnologies, Technican/Instructor

Trevor Conquest, Conquest Communications, Brisbane, Australia, fiber optic training.

Training In The Frozen North
Bill Graham (lower left above with the white beard) lives near Toronto and has probably trained half of Canada in fiber optics. Bill sold his company, Missisauga Training, several years ago to another active Canadian
who took over the training but Bill is still active as a FOA Director and promoter in Canada. Bill is famous for training in the Frozen North, still in competition with Ian Gordon Fudge of Fiber DK in Denmark to see who has trained closer to the North Pole. Bill always sent us photos from his trips, like these:
Bill Graham  Bill G Bear
Netcom Training and maybe one of Bill's students near the Arctic Circle
Frozen North Frozen North

And yes, getting there was half the fun. That plane on the right  is a DC-3, probably more than 70 years old!

Bill G Book

Bill is also an expert speaker, first  a  learning from
Toastmasters and then becoming a leader of the organization. He's written a short guide for speakers that we recommend to everyone who has to get up before a crowd and speak. You can get "So You Are Presenting" by Bill Graham on Amazon.


FOA will be 25 years old in July - watch for more articles on FOA history.

Worth Reading - News Summary

Each month we read hundreds of newsletters and online articles. These are the ones we think you will find "worth reading."

ISPs Raise Speeds and Suspend Data Caps in Response to the Coronavirus Pandemic - Consumer Reports.

Coronavirus School Closings Expose Digital Divide - US News  

Understanding The True State Of Connectivity In America - 65% of US counties receive broadband speeds below industry reports.

CityFibre closes FibreNation acquisition - UK - The addition of the new fiber assets has led CityFibre to raise its fiber to the premises (FTTP) deployment plans from 5 million to as many as to 8 million premises. From Lightwave.

Why Businesses Need Fiber Connectivity, from Spectrum CATV. Yes, it's a sales pitch, but they make good points and it indicates they are serious.

DIRT Report On Damage To Utilities Common Ground Alliance (CGA) annual DIRT report provides a summary and analysis of the events submitted into CGA’s Damage Information Reporting Tool (DIRT) for the year 2018. The complete report is available for download here. In addition, there is an interactive dashboard that allows users to filter the data more  by factors contributing to damages.

Cedar Falls, Iowa is monitoring a bill in the Iowa State House that could threaten their municipally owned and operated broadband utility network.  Senate Study Bill 3009, introduced by Sen. Dan Dawson, R-Council Bluffs is ibacked by commercial service providers.

Structured Cabling News - a website and weekly newsletter about cabling.

Self-Driving Trucks Hit The Roads in Texas. Waymo (Google) tests their vehicles in Texas.

Utilities Team Up on Plans to Run Fibre Through the Sewers (Again!)
Five water utilities have teamed up with infrastructure firm SSE Telecoms on plans to lay fibre optic cables in the UK’s sprawling network of waste water pipes. We first reported on this proposed method for fiber installation in the FOA Newsletter in 2012! It has not exactly taken off!)

The Internet Master Plan for New York City. The New York City Internet Master Plan is a comprehensive framework for the infrastructure and services that provide connectivity to New York City residents and businesses. This Master Plan will guide City actions and public-private partnerships to transform New Yorkers’ access to this essential infrastructure for generations to come.

Corning Has Removed The "Dust" from "Dust Caps."
Corning "CleanAdvantage(tm) Edge cables have factory cleaned connectors and caps to keep them clean.

Fiber Trivia From Corning.

Why understanding PoE now is crucial for electricians - To ring in the new decade, IDEAL Networks is urging today's electricians to master new skills and equipment to cope with the growing use of PoE in intelligent lighting applications.

Smart City Projects: Smart city initiatives are underway across the country. But they face funding and technology challenges. Many cities want to upgrade infrastructure to improve resident experience, safety and to generate revenue.

Cloud Computing Is Not the Energy Hog That Had Been Feared - The digital services churned out by the world’s computer centers are multiplying, but their energy use is not, thanks to cloud computing, a new study says.(NYTimes)

Data Centers’ Impact on Climate Change May Be Overblown - Researchers argue that new technology and greater efficiency could offset energy demands (onezero)

The Future Of Work Is Skills - So Stop Worrying About Degrees - The reality is the future of work is about skills, not just degrees. (FOA Newsletter Feb 2020)

Want a White-Collar Career Without College Debt? Become an Apprentice (NYTimes)
Apprenticeships probably began with the first jobs, where young people work under experienced craftspeople to learn a trade. In the last century, they became more organized under labor unions like the International Brotherhood of Electrical Workers, one of the FOA's oldest and biggest approved school systems. Today, apprenticeships are expanding as young people look at viable alternatives to loading themselves with debt while attending college.

The job market is hot. So why are half of U.S. grads missing out?  

VIAVI Books On Fiber Optic Testing (2 volumes) - They're back!

books  book 2

Besides the FOA reference materials, two JDSU/VIAVI textbooks, Reference Guide to Fiber Optic Testing, Volumes 1 and 2,  were used as references for some of the FOA courses and are recommended for instructors and students. The books are available from VIAVI as eBooks and the everyone should download them and recommend them to others.Download yours now. Volume 1. Volume 2. Viavi Books

50th Anniversary of The Development of Low Loss Fibers
A history of the development of low loss fiber, a fascinating story by Jeff Hecht on the OSA (Optical Society of America) website.

How OFS Makes Fiber

Interesting YouTube video on how fiber is made. Perhaps a little too much "show biz" but fascinating. If you have ever seen fiber manufacture, look at this video. You will be amazed at how big preforms have become!

How Nexans Makes Copper Cables - compare the process to fiber - don't most of the machines look similar?

The True Cost of Telco Damages (what backhoe fade or target practice can cost)

Rural Electric Cooperatives: Pole Attachment Policies and Issues, June 2019.

Ckearfield-FOA Certification Training Clearfield is now offering their customers an FOA CERTIFICATION course. This course provides a basic understanding of fiber optic technology, as well as Clearfield product knowledge and how Clearfield’s integrated product systems work together in a fiber network.

Substandard Contractors - Fiber Optic Knowledge Doesn't Always Trickle Down  (EC Mag)

Another Source Of Articles On Fiber

FOA President and editor of this newsletter Jim Hayes has also been writing a column in Electrical Contractor Magazine for almost 20 years now. Electrical contractors do lots of fiber work and this column has covered some topics they are interested in including installation processes, network design, fiber applications and a lengthy series on dark fiber - what it is, how's its used and how it benefits the growth of communication. A recent web site redesign makes it easier to browse all these articles - just go to and you can see all of them.

Upgrade Your KSAs

You should consider upgrading your KSAs - your knowledge, skills and abilities related to your work in fiber optics and keep up to date with new applications. It should help your business "bottom line" - income and profit, that is.

FOA has just the place to learn -
Fiber U. Fiber U offers 15 free online courses starting with an introduction to fiber optics for those new to fiber and including courses covering installer skills topics (basic fiber, basic skills, OSP construction and installation, testing and OTDRs), a course for those designing fiber optic networks, and six courses on specific applications of fiber optics (FTTx, OLANs, fiber for wireless, cell tower antennas and DAS, and data centers.)

If you are a working fiber tech, the applications courses can enhance your ability to get business in those areas because you will know the specifics of the applications. With so much work being done on wireless (small cells, 4G/5G) and data centers (small to hyperscale), understanding these applications can certainly improve your prospects in those markets.

Learning more from the skills courses like testing and OTDRs is a no-brainer, but you might look at our upgraded
"Basic Fiber Optic Skills Lab" too. You might find it will help you upgrade your skills, but we have another aim for the basic skills self-study.

If you are a contractor who has new employees that you want to upgrade their skills or apprentices who are just starting in fiber optics, the
Basic Fiber Optic Skills Lab lets them use their own tools and components to learn installation skills they use daily on the jobs. The new workbook we've added to the basic skills lab guides the person taking the course through the exercises and provides worksheets to record the results of their labs. We've upgraded the virtual hands-on (VHO) tutorials also and made them so you can download and print them to help you with the steps in the exercises.

Can You Learn Hands-On Skills Online?

basic skills lab

Knowledge is easy to learn online, but learning skills requires "hands-on" practice and that requires tools and components to practice with. Here at FOA, we've been working on an online course that could help many techs learn new skills or improve others using an online self-study course and their own equipment.
Recently, we have updated the materials in the Fiber Optics Basic Skills Labs which includes cable preparation, splicing, termination and testing. And we have created a Basic Skills Labs - Copper Premises Cabling to cover UTP (Cat 5) and coax copper cable processes. As with all Fiber U courses, these are free.
The course on
Fiber U called "Basic Fiber Optic Skills Lab"  introduces you to the tools and equipment then takes you through cable prep, splicing, termination and testing. Recently we have been working on improving the course to make it easier and more effective.  We've added a Basic Skills Workbook for each topic in the course that you can download to guide you through the study and hands-on exercises. We've updated what we call "Virtual Hands-On" (VHO) tutorials where we use an analysis of the activities to break them into step-by-step instructions that help you learn the processes. We've also added new technologies like splice-on connectors (SOCs) that have become very popular.

we have created a Basic Skills Labs - Copper Premises Cabling to cover UTP (Cat 5) and coax copper cable processes. It has a lab workbook, VHOs on each topic and quizzes to allow you to check your knowledge. If you have to tools, you can do all the processes on your own.

If you are a newcomer to fiber optics, have completed the
Basic Fiber course and already have a set of fiber tools, this course will help you to learn how to use the tools and learn basic fiber installation practices which you can practice using your own equipment. If you are a CFOT or working tech now and want to learn some new processes, this can help you too.

Like all Fiber U courses, the
Fiber U Basic Fiber Optic Skills Lab is free.

10GPON Update In FOA Guide

FOA has updated its page on FTTH PON protocols to include the latest standards for 10GPONs. There are three standards, NG-PON2, XG-PON and XGS-PON. As is common with all communications networks, work on upgradeing network capability and speed starts as soon as a network is introduced and PONs are no exception. GPON has been the most widely used PON scheme for both FTTx netowrks and passive optical LANs (OLANs) and GPON has been upgraded to several versions with higher transmission speeds and higher power budgets to allow greater distance, higher split capability, or both. The assumption is that a fiber network has a lifetime of up to 40 years, so upgrades to GPON have assumed that they will use the same passive optical network architecture and fiber type (G.652 singlemode.)

Furthermore, upgrades have been designed around coexistence with current GPON networks. By utilizing different wavelengths, it is possible to have these newer, faster networks sharing the same passive optical network as the original GPON system, allowing offering higher speeds to users while continuing to serve current users without disruption. Some commercial users can take advantage of higher speeds while typical consumers are well served by GPON. One of the big advantages of the PON upgrade standards is the ability to overlay networks. Thus a city could operate one regular GPON network for consumer FTTH use and have another, faster network operating on the same cable plant independently, offering a higher level of service and security.

More on PON Protocols in the FOA Guide.

Introducing Lennie Lightwave's Guide - 25th Anniversary Edition

FOA has reprinted "Lennie Lightwave's Guide" on its 25th anniversary in a special print edition.

Lennie 25th Anniversary  

Many of you have used the current online version of Lennie's Guide on the FOA website. Now you can have a slick printed version - real paper - you can hold in your hand and read. Leave a copy on your desktop to impress your friends, or on the table in your company's reception area instead of out-of-date magazines. Give them to your customers and employees to help them learn fiber optics. Use it to prepare for FOA certifications. FOA will be giving them away at conferences like the IMSA Annual Conference in New Orleans later this summer.

You can get your own copies of
Lennie Lightwave's Guide at, only $9.95US.

Another Look At Connector Contamination

Brian Teague of Senko Advanced Components sent us the results of an interesting experiment he ran to show an unusual effect of the contamination on a connector. He started with a clean SC/UPC singlemode jumper, shown in the 400X image to the left. Then he connected it to a 1310nm laser test source and measured the power out of the fiber with a fiber optic power meter. Then he disconnected the connector from the meter, touched the end to his finger, contaminating the end of the ferrule as you can see in the image on the right.

But then he connected the dirty connector to the meter and measured the power again. The power was decreased by 0.22dB. Yes, the contamination on the connector acted as an attenuator to reduce the power considerably. Think what would happen if you them mated it to another connector. Not only would you see the attenuation caused by the contamination, you will probably see even more loss caused by the gap created by the flakes of skin.

That's why you should inspect, clean and inspect again to ensure all connectors are clean before testing or making connections.
contamination of fiber optic conector

FOA Guide


We are continually updating the Online Reference Guide to keep up with changes in the industry and adding lots of new pages of technical information. When you go to the FOA Guide Table of Contents to see the latest updates - look for New.

PON Protocols in the FOA Guide. 10GPON Update In FOA Guide

Basic Fiber Optic Jargon, OSP Fiber Optic Jargon and Fiber Optic Jargon for managers.

FOA has a new page on Restoration
The updated Fiber Characterization page in the FOA Guide goes in to more depth on why fiber characterization is important, what tests need performing and how to interpret results.

Practically every page in the section of the FOA Guide on Fiber Optic Testing has been reviewed and updated, much of it based on the new FOA textbook on testing. This includes pages on measuring power, fiber attenuation, connector or splice loss and cable plant loss. Browse through the testing section and see what's new.

We've started with a page in the FOA Guide on Fiber Optic Network Management that describes what our advisors think is important and created a page to introduce them to the language and technology of fiber optics which we call "Fiber Optic Jargon - Illustrated." Over time, we'll be expanding this section and create a Fiber U self-study course also.

FOA has created a new section of the FOA Guide on OSP Construction.

Inspecting and Cleaning Connectors.
Dirty connectors are one of the major problems in fiber optics, causing high connector loss, high reflectance and contaminating transceivers. Network operators claim that 15-50% of all network problems can be traced to dirty connectors causing connection problems.
FOA Guide section on inspecting and cleaning connectors.

Go to  The FOA Online Fiber Optic Reference Guide.

FOA School Offers Toolkit With Online Training

Slayton tool kit

Slayton Solutions (FOA Approved School #156) is offering a simple fiber optic tool kit that includes a 29-piece set of fiber optic tools and a power meter along with training videos and online instruction for only $499. 29 Piece Kit includes all tools and devices a technician needs to install fiber optic connectors and test optical power.  Information on the kit is available on YouTube. You can contact them for more information at or

New FiberNext Job Board And Savings Club For CFOTs

FOA Approved School FiberNext has created an online job board for fiber techs and a special "savings club" for CFOTs.

Job Board
The Job Board was designed to help connect employers with fiber technicians and other fiber optic professionals. It is a place where employers in the fiber optic market can post job openings and a place where fiber optic professionals can post that they are looking for employment. Please feel free to post an opening or browse for your next job or employee.

Savings Club
FiberNext, besides being an FOA approved school is also a distributor. FiberNext invites FOA CFOT®s to join the “FiberNext CFOT®  Club to get special savings on selected fiber optic products.  Visit to sign up today ”

Recycling Fiber Optic Cable

We received this note from Steve Maginnis, LD4Recycle/ CommuniCom Recycling on recycling fiber optic cable:

We have 3 Processors gearing up to accept fiber optic cable (FOC). As we all know, all FOC is not the same. Several truckloads of “typical” FOC scrap from FOC mfgrs and “typical” FOC and Coax cable have been studied and tested.

Therefore, today you can begin contacting me with the type FOC material or scrap you toss to the landfills today. We need to quantify the expected feedstock. Our expectation for quantities is quite large (tons) but there is a capacity limit. And I do have several processors that can take ALL materials and others that can accept LIMITED types of FOC material and quantity.

Steve Maginnis
LD4Recycle/ CommuniCom Recycling
(Visit our new website)

Safety On The Job

Safety is the most important part of any job. Installers need to understand the safety issues to be safe. An excellent guide to analyzing job hazards is from OSHA, the US Occupational Safety and Health Administration. Here is a link to their guide for job hazard analysis.

FOA also has lots of information on safety: FOA Guide, YouTube video and a Safety Poster

Best Practices Guide For Underground Construction

Best Practices - CGA

We assume you are familiar with the "One Call" and "Call Before You Dig" (811) program, but are you also familiar "Click Before You" and with the people behind it - the Common Ground Alliance and their Best Practices website?

CGA is a member-driven association of 1,700 individuals, organizations and sponsors in every facet of the underground utility industry. Established in 2000, CGA is committed to saving lives and preventing damage to underground infrastructure by promoting effective damage prevention practices. CGA has established itself as the leading organization in an effort to reduce damages to underground facilities in North America through shared responsibility among all stakeholders.

Officially formed in 2000, the CGA represents a continuation of the damage prevention efforts embodied by the Common Ground Study. Sponsored by the U.S. Department of Transportation and completed in 1999, this Study represents the collaborative work of 160 industry professionals who identified best practices relating to damage prevention.
Any best practice or program endorsed by the CGA comes with consensus support from experts representing the following stakeholder groups: Excavators, Locators, Road Builders, Electric, Telecommunications, Oil, Gas Distribution, Gas Transmission, Railroad, One Call, Public Works, Equipment Manufacturing, State Regulators, Insurance, Emergency Services and Engineering/Design.

Read the CGA Best Practices Guide here.

Here are all the CGA resources for damage prevention.

Should Your Company Become An FOA Corporate Member?

Dig Once

The word on the "Dig Once" program is getting out - FOA is getting calls from cities asking us for information and advice. It helps that the current Administration is trying to convince cities of the advantages of installing ducts or conduits when they dig up a street so they don't have to do it again. Here are some links for more information.

The DoT page on the administration’s Executive Order:
From the Council of State governments:
From the city of San Francisco:
An article about Dakota County, MN:

And the one to download and hand out:
A “How To” Guide from The Global Connect Initiative:

Useful Online Resources

We often have contacts give us online links for useful information which we like to share with our readers. Here are two:

Why We Warn You To Be Careful About Fiber Shards

Fiber in Finger

Photo courtesy  Brian Brandstetter,  Mississauga Training Consultan

FOA Facts

FOA is a non-profit professional association chartered to promote professionalism in fiber optics through education, certification and standards. FOA is mostly known for  certifying techs - mostly CFOT®s -Certified Fiber Optic Technicians - but also may be CPCTs - Certified Premises Cabling Technicians or corporate members involved in fiber optics.

FOA is a "virtual organization" - we have no "brick and mortar" presence. We operate over the Internet with operations centered in California, with active workers and volunteers in locations as diverse as Texas, Ohio, Canada, Singapore, Malaysia, Denmark, South Africa, the Middle East and many more.

Being a virtual organization, FOA has very low overhead, allowing us to offer cost-effective certifications and many free programs to support our industry.

CFOT Total
As of today, FOA has certified this many techs. About 90% come from our schools but many experienced techs have become FOA CFOT-certified directly through our "Work-to-Cert" program.

FOA has almost 200 approved training organizations in about 40 countries around the world around the world.

FOA Certifications Now Last For 3-Years

Beginning in 2019, all FOA certifications issued or renewed will be for a period of 3 years. Most certification bodies worldwide have standardized on 3 year certifications. FOA has been working with a number of organizations that use our programs but have standardized on 3 year certifications. FOA has decided that it is time to change our policies to align with the majority of other organizations.

Remember that FOA certification renewals include all the certifications one individual has for one price. FOA does not charge for any additional certifications, so, for example, if a CFOT also has specialist certifications like the CFOS/T or CFOS/S, they are included at no additional cost when the basic certification is renewed.


FOA has 14 fiber optic certification programs covering every aspect of fiber optic network design, installation and operation.

Primary Certifications: CFOT (basic fiber), CPCT (premises cabling), CFOS/O (outside plant, taught with CFOT included) and CFOS/D (fiber optic network design).

Skills Certifications (for installers and techs, requires CFOT): CFOS/S (splicing), CFOS/C (connectors/termination), CFOS/T (testing), CFOS/FC (fiber characterization).

Applications Certifications (for techs or anyone, including managers and supervisors): FTTH (fiber to the home), CFOS/L (optical LANs), CFOS/DC (data centers), CFOS/A (fiber to the antenna), CFOS/DAS (distributed antenna systems) and CFOS/W (fiber for wireless)

(what you are reading)

FOA monitors the trade press, websites and other resources continually to look at what's happening in many technologies that affect fiber optics. We're tracing technologies as diverse as wireless, IoT, autonomous vehicles, smart cities, energy, or anywhere fiber is used to bring news to our readers.

FOA continually updates our technical materials, online and printed, and our curriculum to ensure our readers have access to the latest technical information and our schools teach the latest technology and applications. Our printed books are being updated right now.

FOA Guide
FOA created the FOA Online Guide as a non-commercial trustworthy technical reference almost a decade ago so the industry would have a reliable technical reference. In the last year, over 1million visitors downloaded about 4 million pages of technical information.

FOA offers free online self-study programs at Fiber U. In 2017, the number of online sessions doubled to 200,000. Many of those are preparing for FOA certification programs - taking courses at our schools or using the "Work-to-Cert" program. Some of our schools are requiring Fiber U programs as prerequisites for their classroom courses so they can spend more time on hands-on activities.


FOA offers over 100 educational YouTube videos that have been viewed 2.4 million times.

FOA offers its training programs to other organizations at no cost to help them train their members properly in fiber optics. For example, FOA has been working with the Electrical Training Alliance (IBEW/NECA) for over 20 years, training their instructors for their apprenticeship programs. We work with many other organizations and companies to provide the materials they need.

FOA has about 300 corporate members - companies in various aspects of the fiber optic industry worldwide that we list online and offer discounts on certifications and renewals.

FOA provides speakers for many conferences and even presentations for use by other organizations to educate people on the aspects of fiber optic communications.

FOA has a program to provide
classroom materials for STEM teachers (science, technology, engineering and math) introducing K-12 students to fiber optics and creating science projects.

FOA provides forums for discussion on various social media. Our LinkedIn groups have about 5,000 members each. If you are not joining us on social media yet, please do.

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Interested In A Career In Fiber Optics?

Careers in fiber optics

FOA has created a new YouTube video to introduce students to careers in fiber optics. It was made for showing to high school and junior high students interested in tech careers but anyone interested in a possible career in this field will find it interesting. If you have kids in school or know teachers, let them know about this too. Watch the FOA Careers In Fiber Optics Video on YouTube and visit the
FOA Careers In Fiber Optics web page at


Fiber Optic Education For Students At Any Age 

We hear about fiber optics all the time - it's in the news whenever we hear articles about high tech, the Internet and communications, and many communities are getting "fiber to the home." But few people really understand fiber optics or how it works. FOA is focused on educating the workforce that installs and operates these fiber optic networks but we're always getting inquiries from STEM (science, technology, engineering and math) teachers who want to introduce fiber optics to younger students in K-12 grades or technical schools.

We start with the FOA Careers In Fiber Optics Video on YouTube and visit the FOA Careers In Fiber Optics web page at These are for students who think they might be interested in careers in fiber optics and want to know more about what fiber techs do.

Teachers for fiber optics
Using red laser light (a VFL here but a laser pointer works also) to show how fiber guides light.

FOA has begun developing a series of YouTube videos intended for teaching students in elementary, middle and high schools about fiber optics. The first FOA video is titled "Fiber Optics For Teachers." With this video, we show teachers how fiber works and carries signals and then explains simple experiments to demonstrate how fiber optics works in the classroom using some plastic fiber and a laser pointer. Since many teachers do not know where to get the fiber, the FOA offers to send them a sample for use in demonstrations in their classroom (USA only right now.)

At the end of the video, teachers are given directions on how to request samples of the plastic fiber from the FOA.

This video joins the "Fiber Optics Live" series How Light Travels In A FiberFiber Attenuation and Connector Loss that show how fiber works using simple experiments that can be duplicated in any classroom. More videos will be coming soon.

If you have kids or know some teachers who would be interested, please send them to the introductory video Fiber Optics For Teachers  and we'll be glad to help them get started with some entertaining programs for their classrooms.

Resources For Teachers In K-12 And Technical Schools

Teachers in all grades can introduce their students to fiber optic technology with some simple demonstrations. FOA has created a page for STEM or STEAM (science, technology, engineering, arts and math) teachers with materials appropriate to their classes. Fiber Optic Resources For Teachers.


If you have kids in school or know teachers who are interested, send them to the FOA page Fiber Optic Resources For Teachers.

Should Your Company Become An FOA Corporate Member?

As all FOA individual members know, they join the FOA by becoming certified, mostly taking their CFOTs but some CPCTs,  either by attending a FOA approved school or joining directly based on field experience (our "work to cert" program.) Over the years, we've been contacted by manufacturers, contractors, consultants, and other types of organizations who ask about becoming members.

We don't certify companies or organizations, we told them, so we were not sure what we could offer as a benefit of membership. But then, companies asked about using our educational programs to train employees, how they could get listed on the FOA website as service providers or if they could get a quantity discount on membership or certification for all the FOA members working for them. That began to sound like a benefit for being an FOA corporate member. And providing a list of useful suppliers to the market could be a benefit to the industry as a whole.

So FOA has quietly been letting companies and other organizations join the FOA to take advantage of those benefits so we now have several hundred corporate members. We've put then into a database and listed them on the FOA website in map and list form. Here's the map.

FOA Corporate members

The online
map and list can be used to find suppliers and service providers.

The map, like our map of schools, lets you find the FOA corporate members close to you.  The table form lists them by category: Installer/Contractor, Component Manufacturer, Installation Equip. Manufacturer, Transmission Equipment, Services/Consulting, Distribution and Users of Fiber Optic Networks. You can sort the tables to find members meeting your needs, e.g. by location, certifications offered, etc. Click on any column heading to sort that column; click twice to sort in reverse order.

How Does An Organization Become An FOA Corporate Member?

Simple, just fill in the online application form. When your application is accepted, you will be asked to pay the one time membership fee - $100US. You will then be listed on the online  map and list, have access to exclusive FOA educational materials for your employees and get discounts on certifications and renewals. 


Events of Interest: FOA now posts events on our LinkedIn groups, Facebook page and other social media

FOA on LinkedIn

FOA has a company page and three LinkedIn Groups

FOA - official company page on LinkedIn
FOA - covers FOA, technology and jobs in the fiber optic marketplace

FOA Fiber Optic Training - open to all, covers fiber optic technology and training topics

Grupo de La Asociación de Fibra Óptica FOA (Español)  


FOA Logo FOA Resources

FOA Standards:

FOA offers free standards for datalinks and testing the installed fiber optic cable plant, patchcords and cable, optical power from transmitters or at receivers and OTDR testing.
Look for the "1 PageStandard" web page and in the FOA Online Reference Guide.

View the  FOA YouTube Video On FOA Standards 

NECA/FOA 301 Fiber Optic Installation Standard

NECA 301
Standards cover components and systems and how to test them, but rarely get into installation issues. The FOA NECA 301 standard which covers installation of optical fiber systems has been revised for the second time, adding considerable new materials. This standard is derived from FOA educational material put in standards form and approved by ANSI as an American National Standard. It's specifically written to be used in contracts to define "installation in a neat and workmanlike manner." The standard is available from NECA.   FOA members can go here for instructions on how to download your free copy.


Fiber U

Free Fiber U Self-Study Programs

FOA's "Fiber U" free online self-study programs help you learn about fiber optics, study for FOA certifications or use them to help create "blended learning" classes. There are two new free online self-study programs on Fiber U. Fiber Optic Network Design is for those interested in learning more about how to design fiber optic networks or studying for the CFOS/D certification. FTTx is for those wanting to know more about fiber to the "x" - curb, home, wireless, etc. - or studying for the CFOS/H certification.
Got to Fiber U for more information.

Fiber U Online Self-Study Programs Offer Certificates of Completion

FOA has been offering quite a few free online self-study programs on Fiber U, our online learning site. We are always getting questions about getting a certificate for completing the course online, so we have setup an option to take a test online and get a certificate of completion for these online courses.

Fiber U certificate

While it's not FOA certification, FOA will recognize a
Fiber U Certificate of Completion as background experience to qualify for applying for FOA certifications. We also intend to expand the program to more specialized topics as preparation for FOA specialist certifications.

If you have associates that want to get started in fiber, have them take this course online to get started. Go to  Fiber U and get started.

FOA Books And Publications

Updated Books
FOA Reference Guide To Fiber Optics  FOA Reference Guide To OSP Fiber Optics

Many textbooks are behind the technology because they are rarely updated. FOA really keeps our textbooks up to date. We did a major update a year ago and another was just completed. The The FOA Reference Guide To Fiber Optics has been updated to reflect new components like OM5 fiber, testing for fiber characterization and more information on installation.

FOA Reference Guide To Outside Plant FIber Optics has been expanded to include an extensive section on outside plant construction taken from Joe Botha's OSP Construction Guide textbook. This additional material is being added to support the new FOA CFOS/O OSP tech certification program which now includes of OSP construction.

 FOA Basic Fiber Optic Textbook Available in French and Spanish

  FOA Reference Guide to Fiber Optics book FOA Text in French FOA text in Spanish FOA Reference Guide to Premises Cablng book FOA Reference Guide to OSP Fiber Optics book  FOA Guide To Fiber Optic Network Design  FOA Outside Plant Fiber Optics Construction Guide

FOA Book on Fiber Optic Testing   FOA Reference Guide To Fiber Optic Testing

Libro de Diseño para Redes de Fibra Óptica en Español - FOA Design Book Available In Spanish Online

Design in Spanish

La Asociación Profesional de Fibra Óptica (The FOA) ha traducido y hecho disponible en Español, la “Guía de Diseño para Fibra Óptica”. Esto para todos los interesados en estudiar para la certificación CFOS/D en su idioma nativo. Puede acceder a la traducción al libro de Diseño en línea utilizando este enlace. La versión impresa del libro estará disponible muy prontamente.

FOA has translated the FOA Guide To Fiber Optic Network Design book and made it available online to those studying for the CFOS/D Certification but whose native language is Spanish. You can access the Spanish translation of the Design book here. A printed version will be available in the near future.

Lennie & Uncle Ted Guides - Perfect For Getting Started

Lennie and Uncle Ted's Guides have moved  to the FOA website. Lennie is the place where many if not most fiber techs begin their education. FOA has just updated the two guides to ensure they stay relevant - more than 20 years after they were first written.

Lennie goes all the way back to 1993 when he was created as the mascot of the original "Fiber U" conference - the same Fiber U that is now the FOA's web-based training site. Lennie Lightwave's Guide To Fiber Optics was created as a beginner's introduction to fiber optics. Over 60,000 printed version of Lennie's Guide were given away and it became one of the first commercial web pages in 1994. Uncle Ted's Guide To Communications Cabling was written a few years later to introduce techs to "Cat 5" - UTP wiring - that had only recently been standardized in TIA-568.

Lennie and Ted's Guides are used in the current Fiber U online self-study programs and are still the best place to start learning about fiber optics.

Lennie and Uncle Ted's Guides are online at the links here, can be downloaded as printable PDFs and are now also available as free iBooks on iTunes.

Lennie Lightwave's Guide To Fiber Optics   Uncle Ted's Guide to Premises Cablling

Lennie Lightwave's Guide to Fiber Optics and Uncle Ted's Guide To Communications Cabling   are now available free to iPad users who can download them from the Apple iTunes store. Of course they are still available online or for download.

You can also find these free guides on the FOA website - go here for all the links: Lennie Lightwave's Guide to Fiber Optics and Uncle Ted's Guide To Communications Cabling  

Download PDFs of Lennie or Uncle Ted.


FOA iPad Apps

FOA LossCalc
FOA Loss Calculator AppFOA LossCalc estimates the optical loss of a fiber optic link. This will save time for the installer of a fiber optic link needing to know whether test results are reasonable and/or make a "pass/fail" determination. It can also help the designer of a link to determine if communications equipment will operate over this link.
By choosing the type of link (singlemode or multimode) and specifying the length of the fiber and numbers of connections and splices, it will calculate the end to end loss of the link. The app has default specifications for singlemode and multimode links or the user may create custom setups with specifications appropriate for any application.



The FOA has many videos on videos, including two Lecture Series (Fiber Optics and Premises Cabling), Hands-On lectures on both and some other informational and instructional videos. For all the videos, go to the FOA Channel "thefoainc" or use the direct links below.

View a complete list of FOA Videos with links to each video on YouTube.

Where Are The Jobs In Fiber Optics? FOA talks about all the applications for fiber optics, what jobs involve and the qualifications for the workers in the field.

Fiber Optics - Live!  A series of videos that use lab demonstrations to show how optical fiber works. 
Fiber Optics LIVE!

Cabling Project Management - what's involved in a copper/fiber/wireless project -advice for the customer and the contractor

Hazards Of Counterfeit Cable

You may have read the stories we have written about the counterfeit "Cat 5" cable made from copper-clad aluminum rather than pure copper. Recently we tried an unscientific burn test on the cable compared to a known good UL tested cable and posted a video on YouTube. You can see the results below.

Counterfeit cable flame test

Counterfeit Cable     Real UL-rated cable

The difference is obvious and the danger is real. Watch the video on YouTube: Premises Cabling Lecture 11: Counterfeit Cat 5 Cabling

View a complete list of FOA Videos with links to each video on YouTube.

View all the FOA Channel  on YouTube.  


FOA Schools

New School:

Midwest Communications Technologies, FOA Approved School #378.

Find a listing of all the FOA-Approved schools here.

Find An FOA-Approved Training Organization

Most inquiries we get regarding finding a FOA-Approved training organization want to know two things: what school is closest to me or what school offers the certifications I need. The FOA has about 200 training organizations we have approved worldwide so finding the right one can be difficult! We've been looking at ways to make it easier, and we think we've got a good solution. In fact we have two solutions.

First we have added a sortable table of all the FOA-Approved schools.

You can also use our FOA Google Map to find FOA-Approved schools.


What Should A Fiber Optics or Cabling Tech Know and What Skills Do They Need?
FOA certifications are based on our KSAs - the Knowledge, Skills and Abilities that techs need to succeed. Read the FOA KSAs for fiber and cabling techs.

School News


We always enjoy feedback, especially when it shows how great some FOA instructors are. These came from students of Tom Rauch, an instructor at BDI Datalynk:

"I took your fiber optics certification courses this past March. I just wanted to let you know that in two weeks I start working as a fiber optic technician with ___ up in ___. You mentioned on the first day of the course that there is always one guy in class who had rubbed his last two nickels together to be there and, in that instance, I was that guy. Now I'm going to be able to provide for my family like never before and I owe it to the certification that I received from you and BDI Datalynk. I just wanted to thank you again."

"Thanks to our tremendously knowledgeable and patient instructor Thomas Rauch, who was not only generous in sharing his wealth of information, but he did so with ease, humor and in a way that invited curiosity and participation. He was encouraging and proud of our accomplishments and helped us learn from our mistakes in a way that did not break our confidence, rather it pushed us to better results the next go around. The hands on labs were just AWESOME!" Just thought you should know what a class act you have representing you in his travels..... but then again you probably already knew that! : )

In almost 19 years at Verizon and having held numerous positions, I have gone through many training sessions. I cannot remember ever having been actually looking forward to coming back to class quickly after lunch, to get back to the hands on activities, and walking away with the sense of empowerment that the information presented was not only relevant but dead on point accurate! I will be signing up for the Outside Plant class on March! I can't say enough good things about Tom and his impact! Feel free to quote me, I can only imagine that he will open so many doors and change so many lives in the years to come, with his style of teaching! Great experience, awesome job!

IBEW and FOA Partner on Fiber Optic Training

The International Brotherhood of Electrical Workers (IBEW) and the National Electrical Contractors Association(NECA) through the National Joint Apprenticeship and Training Committee (NJATC) in a partnership with the FOA has published a new textbook for training IBEW apprentices and journeymen in fiber optics. The new textbook uses the material from the FOA Reference Guide To Fiber Optics with new material and photos from other NJATC training partners.

NJATC FOA Textbook

Quote from one of our certified instructors: I want to thank you and your organization for all the resources you provide for the students and the opportunity to offer the certification to the students. The fact that you published the book yourself to get the cost down and the unlimited free resources on your website shows a commitment to the public that is second to none. I let it be known to the students that the FOA is the best in the industry at supplying knowledge and resources related to the communication industry. I look forward to passing on the information that you provide for the industry.



Good Question! Tech Questions/Comments Worth Repeating

New: The FOA Fiber FAQs Page (FAQ s = frequently asked questions) gathers up questions readers have asked us and adds tech topics of general interest.

Questions From FOA Newsletter Readers

April 2020
Restoration Time
Do you have any statistical data on how long (on average) it takes for a utility network operator to detect and pinpoint the exact location of a fiber cut?
A: We don’t have any information on the average time it would take to find a fiber fault and like all averages, it might not have a lot of meaning.

Many fiber optic links today have alarms that indicate loss of transmission so they tell you immediately when the link goes down. Identify the link and the fiber connection.  Then it becomes a matter of troubleshooting and eliminating causes. Sometimes even when reconnected the equipment requires a system reset to get started.

First - check the power on the equipment

Secondly: determine if someone was doing something in the equipment area that might have caused a problem. We do know of a link that was brought down because an executive giving a tour disconnected a live link to show someone a fiber connector! If someone was working nearby, check that area first - patchcords, cables, etc. Don’t forget to check work records to see if a crew is working around the cable plant at that time. It’s possible a crew installing new cables damaged old ones. See the FOA newsletter for this month for what installers do on aerial cable plant or last month for underground

If it appears to be in the cable plant and nobody is working near it, OTDRs are generally used for troubleshooting. They get you into the area where the problem is and them it’s finding it manually. Underground it’s often contractors digging or boring, overhead it’s just poor workmanship - or as a guy from Bonneville Power put it, it may be “target practice” although animals damage aerial cables too.

FOA has a page on restoration and some of our instructors do seminars on it.

Time? If there are trained techs available, finding the problem can take less than an hour. If not, it can take a lot longer. Repair can be hours or days if the proper techs and equipment are not available.

If nonstop service is required, alternative fiber routing is the solution - build a mesh network.

Under any circumstances, having a restoration plan and repair materials should be ready. If tech personnel are not available, a contractor on call is needed.

Can my otdr test upc connectors?  Can I test this distribution without problems?
A: APC and UPC connectors are not compatible. APCs are green, UPCs are blue. See To test UPC connectors you would need a launch cable that is UPC on the OTDR end and APC to to mate to an APC connectors. But if I look behind these green APC mating adapters, I seem to see blue connectors - blue is UPC not APC.  (add photo)

VFL Works On Multimode And Singlemode
Will a VFL for single mode work with a multi mode as well?
A: Yes, a VFL works for either SM or MM fiber. Tight buffer MM is no problem. On patchcords, the ability to see light through the jacket of the cable depends on the color and transparency of the plastic. On buffered fiber, it works well on most 900 micron buffer fibers.

Campus Network Expansion
Any advice for expanding a campus fiber optic network?
A: Here are some thoughts:
  • Building to building can more easily be done with indoor/outdoor cable to get past the 50’ code limit for OSP cable.
  • Many campuses have ducts but they are often crowded. Microducts or fabric ducts are often the solution even if you have to pull out an older cable to pull in new microducts into one old duct.
  • Microducts and blowing microcables are gaining lots of traction for their practicality.
  • Microducts and microtrenching can be what we call “construction without disruption.”
  • We are seeing more and more directional boring - works fine as long as you know where other buried utilities are! Many contractors need to learn more about underground location.
  • People are finally getting the idea about singlemode fiber - now it’s probably cheaper than multimode.
  • Passive optical LANs can save money. Biggest advantage is the upgrade from GPON to 10GPON is seamless - you can even run both simultaneously, e.g. for a student system and a faculty/research system.
  • High fiber count cables are tempting, but require special handling and lots of manhole/handhole space.
  • We’re working with a Corning “Pioneer” (retired engineer) on trying to educate installers about bend radius violations, esp when pulling large fiber count cables.
  • Most installations shortchange manhole/handhole space.
  • Aerial is sometimes used. Lashing to a messenger is probably best. We worked with a school in Canada last year trying to use short lengths of ADSS and it was not cost effective nor was their much applications support for short ADSS links.
  • Line of sight wireless (RF or optical) works across highways and may be cheaper than construction for fiber.

March 2020

Troubleshooting Links
I have a run of 12 Strand single mode fiber from a remote closet back to my main equipment room.  I unpluged it this morning to check another cable and when i plugged it back i have lost communication with the remote closet.  Can you help me with some trouble shooting ideas.  I have already tried a new cable from the termination point back to the switch but still no communication.
A: The first guess is that the fibers are not connected correctly - transmitter to receiver. That’s the first thing to check. The second possibility is dirt on the connector or in the connector housing on the transmitter or receiver. Cleaning might be the solution. Third and worst possibility is the connector was damaged when being disconnected.

Q2: I ended up powering down the switch in the remote closet and plugging the fiber in then powering it back up and it picked up communication again.  Strange ??
A: Nope, makes sense. Many new networks shut down unless they have full duplex communications. If the link is broken, it shuts down until reset.


Cable Installation Guidelines
I am trying to find information on the recommendations regarding fiber underground in conduit. I am looking for industry specific verbiage on the cumulative turn degrees before you need a handhole or manhole. I believe it is 180 degree cumulative but I can’t find it anywhere.
A: We’ve heard the 180 degree limit mentioned on some conduit but not for fiber optics. For any fiber optic cable pulling, the relevant issues are pulling tension and bend radius.
We know of no specific standards or guidelines on conduit bends for fiber optics. It has many factors, including conduit size and type - there are many types, length of the pull, radius of the bends, type of fiber optic cable and lubricants used, if any. For the cable, there are thousands of fiber optic cable designs that vary in diameter from ~3mm to ~30mm depending on the type of cable and number of fibers, the stiffness of the cable and the location and type of stiffer/strength members and the method of installation - pulling or blowing/jetting. And for locations as far North as you are, temperature can be an issue as cable gets stiffer when colder!
For any given installation, corners are generally accommodated by handholes/manholes and pulling done from handhole to handhole with figure-8ed cable pulling techniques to prevent cable damage by excessive tension or bending.
FOA has a section of our Guide on OSP construction: Outside Plant Fiber Optic Cable Plant Construction and in that is a section on OSP installation. For specific cables or conduit runs, we’d suggest talking to the application engineers at cable manufacturers who can give specific advice.


Minimum Link Length
I have a question regarding minimum fiber optic distances for horizontal runs. Is there a minimum distance for a horizontal fiber optic run? Any information regarding this would be greatly appreciated. Thank you for you help!
A: The answer to your question is for the most part no, there is no minimum distance for a fiber optic link. For example, fiber is used in offices, data centers, etc. sometimes connecting equipment on a single rack. And there are many fiber optic links used on platforms - aircraft, helicopters, ships, etc. - and in command posts.
Most of the Ethernet standards are based on a 2m minimum, but also most are defined by a maximum length. For multimode systems, the max length is mainly a bandwidth issue, so shorter links are no problem.
For singlemode links, the bandwidth is not an issue, it’s the power budget, limited by the transmitter power and receiver sensitivity, translated into the loss of the cable plant. But for receivers, often they have not only a minimum input power limited by their baseline noise but also a maximum power they can have before saturating and causing high bit error rates. See “Power Budget” on this page in the FOA Guide. So if a singlemode link is short, the receiver can be overloaded so an attenuator is used at the receiver.
There is a secondary problem with singlemode systems, reflectance. Reflections from connections can cause problems with both transmitters and receivers, a topic covered in the link given above. The reflectance problem can be solved with APC connectors.
The FOA Guide has many pages on links, networks, reflectance, testing, etc. that you may find helpful.

PON Troubleshooting
I have question about DBM IN GPON system with splitter 1:64. I spliced 2 fiber from splitter to customer going through 4 splicing points and when I measured the loss at the end (customer) the #2 fiber was fine  but the #1 fiber was down 12 dB. I checked the fiber with OTDR without splitter and it looks fine. What you think is the problem?
A: You need to test the splitter itself to make sure all ports are good.

February 2020

Fiber Flexibility and Longevity
Q: When I think of glass, I think of a material that is not very flexible. If you try to bend most glass, it will break. So it is rather remarkable  that you can bend a fiber and not crack it, even though the strands are quite thin. Perhaps it's not a good idea to bend fiber too sharply? I was talking to the people who maintain the fiber network at the university here. They tell me they have a problem when fiber gets to be about 15 years old, it will start to become brittle. If you flex it, it will crack or break. Is this a common problem? How long can fiber be expected to last before it becomes brittle? Is fiber that is manufactured more recently have a longer life-span?
A: Fiber is quite flexible. One demo I did when I taught classes was to walk up to a large window and push on it, telling everyone to watch the reflections to see how the glass flexed. I can flex quite a lot. Like most materials, as it gets smaller, it can bend more easily because the stress is less across the cross sectional area. Consider a bar of steel 1” in diameter compared to a piano wire or banjo string. Most things break because either they are overstressed or there is some impurity in the material that focuses the stress and the crack propagates from there. Ever cut glass? You scratch it and stress it along the scratch line and its maps off - called cleaving - where the stress concentrates along the induced fault. Fiber is extremely low in impurities - a matter of how it’s made from raw materials, not melted sand like most glass - that’s part of what makes them have such low loss (efficient transmission) and high strength. A glass fiber is much stronger than steel of the same size. Corning explains it here.
 The brittleness of older fiber is due to the migration of moisture up the cable into the glass. The H2O becomes the OH radical which interacts with the glass to reduce its strength. Most cable companies say their cable today protects the fiber well enough that it should last 40 years, but where fiber is terminated or spliced and exposed to the air, it can get brittle and be hard to handle in 10 years or more. Older fiber had shorter lifetimes simply because we learned to make fiber coatings and cables better at sealing fiber from the ambient atmosphere.

Fiber Choice for LANs
Many manufacturers or suppliers worldwide emphasize the use of OM4 multimode optical fiber for the LAN. Does single-mode fiber not provide greater bandwidth than multimode? Do they imply that single mode optical fiber should only be used for long distance applications and not in LAN environments?
A: Multimode fiber is acceptable for LANs up to 10 gigabits/second and up to 550 meters depending on the type of fiber and Ethernet version. See this page for a complete list of network specifications.Higher versions of multimode fiber OM2-OM3-OM4 have higher bandwidth capability. OM5 is a version of MO4 that also supports wavelength division multiplexing with VCSEL sources in the extended wavelength 850-950nm range. OM1 is a earlier fiber with a different core size that has not been designed into new systems for almost 20 years. LANs can use singlemode fiber for all versions. Singlemode has longer distance capability (up to 40km) and virtually infinite bandwidth. See the singlemode specification in the link above. Singlemode is also used in passive optical LANs that can be much cheaper to build than conventional networks. See this page  for information on optical LANs (OLANs) including passive OLANs based on FTTH GPON technology.

Testing Pigtails
Q: A customer said he said he would test 100 foot pigtails with OTDR. I question that practice and think OLTS Tier 1 and microscope test for defects,
A: Pigtails do not have a connector on one end so that makes OTDR testing more justifiable. Clean connector, mate to connector on long reference cable, check connection and length. OLTS testing would require using bare fiber adapter or temporary splice and might not be very accurate.

What Is A Ring Network?
If according to the TIA or ISO structured cabling standards the fiber optic campus backbone must be star-hierarchical type, how should a fiber optic "ring" be built? to always ensure connectivity on a LAN?
A: A “ring” network consists of a series of links connecting equipment (nodes) in series until the last one connects back to the first. Since the links are communicate in both directions, the network can still operate if any one cabling link or equipment fails. Today, survivability is usually ensured by using a “mesh” network; the architecture of data centers, the Internet or phones. In addition to having a series connection of nodes, there are other interconnections that provide for multiple alternative paths. See Networks in the FOA Guide.

Testing Samples Not Everything
: Instead of testing everything, how does one determine how many fibers or components to test for a reasonable statistical sampling?
A: The relevant term is AQL - acceptance quality limit - a term that is used for statistical sampling for testing. Here is a web page that explains it: Let testing and inspection evolve. At first test thoroughly, but drop testing anything that never fails, it’s a waste of time. Qualify vendors and test trusted vendors less. 

Fiber Lifetime
I am often ask how long the fiber we are deploying today will last or be useable , I typically say something like it will last at least 20 years and that no one really knows how long it can be used.   What is the oldest fiber optic network or longish segment that is still in production that you know of?
A: Current cables are probably good for 40 years or so. Today there is some fiber being used by telcos from the late 1980s and lots form the late 1990s and early 2000s. Lots of OPGW (optical power ground wire) is in use up to 30 years old. Some of this old fiber is being used at 10Gb//s. But remember that fiber from 20 or 30 years ago may have limitations on bandwidth, since both chromatic and polarization mode dispersion has been reduced in newer fibers for higher speed networks. And spectral attenuation of older fibers may be higher and have the water peak at 1383nm that can affect wavelength-division multiplexing systems. But the weak point may not be the cable or fiber, but the splice and termination points where bare fibers may be exposed to the elements. It's not uncommon to find these fibers have become brittle and are hard to work with. What we always tell people is if it’s working, leave it alone. If you want to upgrade to higher bit rate systems, use fiber characterization to determine if the fibers are capable of use at higher speeds.

Crossed Connections
If a FO connector is crossed connected i.e Rx connected Rx and Tx to Tx at both end, will it works?
I know in theory it will not due to light circuits arrangement, but is there SFP in the market can tolerate that? 
A: We do not know how a SFP could sense and change polarity unless it had an optical switch inside the module. A transmitter is a laser or LED and a receiver has a photodetector. Unless one could have the devices change function, changing polarity would be impossible.

Construction Near Underground Fiber
What is the recommended distance for any new building construction to build near underground fiber duct channel?
A: We do not know of any standards or codes related to construction near fiber or other underground utilities. Common sense dictates that one stay far enough away to prevent accidental damage, so adding 5-6 meters(15-20ft) from the areas of construction makes sense.

Can you guide me some websites or pages where I can learn more about Gpon Technology please?
A: FOA Guide has a big section on FTTH and OLANs using GPON technology. Follow those links,

Splice Loss
Q: We are installing 216 fiber aerial cable for 12km with 2 splicing points. We use 3 different fusion machines and they report that all splices are 0.00db. But when we check using OTDR we get above 0.04db. The question is how can we get below 0.04db splicing loss?
A: The loss results from both fusion splicers and OTDRs are estimates, with considerable uncertainty. The splicing machines estimate based on the optical images of the fibers. The OTDR estimates loss based on fiber backscatter and may give significant differences depending on the direction of test. The differences you quote are within the uncertainty of the two instruments.

Cheating On Link Length
I have a fiber run for a camera starts at location A to location B it is 467 feet.  Location B jumpers through to location C which is 2060 ft at location C. Transceivers areSFPs ONLY GOOD UP TO 1800 ft, but this company only has a multimode system. Is there something i can do to make this work?
A: It might work as is, since electronics are usually quoted with conservative specs and will work farther than specified most of the time. If you have several SFPs, test the output power to see if it exceeds specs and choose the 2 ones with highest power. If that still doesn’t work, contact SFP manufacturers for higher power units.

Pulling Cable
: I’m having trouble finding much information on the matter. What type of swivel should be used to pull fiber and what would be the correct way to pull armored fiber.
A: Start  on the FOA Guide here and go here for types of swivel pulling eyes. with and here are sources It’s not common to “pull” armored cable since it’s designed for direct burial, but a kellums grip on the jacket will generally work.

Errors In A Data Link
: What is the significance of bit error, and what is the acceptable rate for communications and submersible vehicles?
A: On any data link, there is an acceptable amount of error that can be tolerated. If it’s a digital voice link, a BER 10E-6 (1 error in 1million bits) is acceptable without affecting voice quality. If it’s a link to your bank, the typical standard is a million times higher (10E-12). Link protocols usually have ways to determine BER, like attaching a checksum to the end of a data packet and having it checked at the receiving end. If a error is suspected, the packet will be discarded and retransmitted. Here is a tutorial on BER and an explanation of errors in a a fiber optic link.

Math of Fiber Optics
Do you by any chance recommend any books as an introduction to understand the mathematics of fiber optics? Fiber optics confuses me,  particularly how so much data can travel over light without interfering with each other, 
A: If you are interested in information theory, that’s really covered by Claude Shannon at Bell Labs 70 years ago. That’s actually pretty simple. Shannon proved that digital data was best and how much data could be transmitted with a given amount of bandwidth (Read more). There are several levels of math associated with fiber optics. The real theoretical basis is probably in dozens of books but I like these:

Top Level: Gerd Keiser  
Middle Level: Jeff Hecht.

If you are interested in non-math explanations, the FOA website has that:
Fiber Optic Datalinks
Wavelength-Division Multiplexing

For testing math (dB loss, metrology, etc.) these links or the FOA book on Testing
Metrology and Fiber Optics
The Math of Insertion Loss Testing - Reference Methods

APC Connectors
Why NOT make the use of APC connectors the new standard for all adds, moves and changes to any campus, MDU or similar application using single mode cable?
A: There is absolutely no reason not to use APC connectors other than the cost is higher and one must be careful if they are used in a cable plant that also has PCs or UPCs because they are incompatible. We recommend them all the time for short links like data centers, passive optical LANs and FTTH where runs of singlemode fiber are short. In fact they are very common in these networks today.

What is normal Range for good power in an FTTH fiber?
A: The GPON specification for downstream power from the OLT is OLT transmitter power should be 0 to +6dBm and link attenuation in the range of 13 to 28dB, which says receiver power the ONT must be a maximum of 13 dB less than +6dBm or -7dBm and a minimum of 28 dB less than 0dBm or -28dBm, so -7 to -28dBm at the receiver.
Upstream, the similar calculation is ONT transmitter -4 to +2dBm  and the receive power at  theOLT is -11 to -32dBm.
See for the full specifications for GPON.

esting Cable Before Installation
Q: Does the FOA publish a standard for assessing single-mode fiber optic cables, prior to use on a specific project?
A: The ANSI/NECA/FOA-301 fiber optic installation standard covers this in Section 4.1. It recommends visual inspection and testing if there is any suspicion of damage to the cable. Many contractors will test a couple of fibers with an OTDR before installing any cable, just for assurance. It requires an OTDR with a pigtail launch cable and a mechanical splice.

Cable Bend Radius
Q: We are working on project where we need to know difference between short term and long term bend radius for fiber optic cable?
A: The bend radius for cables is generally specified under two conditions - under stress, e. g. when being pulled, it is a radius 20 times the cable diameter. Relaxed, after installation, it is a radius 10 times the cable diameter. The relaxed specification, 10X, is considered a long term specification. Some of the new high fiber count cables have different specifications, sometimes 15X or 20X under either condition. Check with the manufacturer for their specific cable.

OTDR Resolution
If testing a 40KM link with 1KM launch and receive cords should I be able to see the connector and cassette splice on each side? My OTDR setup is at 64KM, 300ns pulse and 10 second test at 1310/1550/1625. It shows as a single event so far but with the pulse width at 300ns won’t that combine the events into one event during analysis?
A: You will not be able to resolve a connector and splice close together, especially on a long link like that. 300ns is almost 60m pulse width! You will see an even of the splice and connector combined.

Transmission Wavelength Compatibility
We are looking at the specs for  two devices, A and B. The spec sheet of Device A lists it is capable of MM in 850nm wavelength. The spec sheet of Device B lists it can do MM at 1300nm. If I connect these devices via MM patch cord, what is the impact due to different wavelengths? Will the transmission suffer significant loss or since both are multimode, wavelength is irrelevant?
A: Fiber works at either wavelength, but transceivers do not. The attenuation rate for MM fiber is ~3dB/km at 850nm but only ~1dB/km at 1300nm. But  850nm receivers use silicon photodiodes while 1300 nm receivers use InGaAs. The 1300 detectors are not sensitive at 850nm and vice versa. So while the fiber works fine, the electronics do not. They should only be used with like devices.


Older questions are now available here on the FOA Guide.


FOA "Quickstart Guides"

In our continuing quest to help people understand how to test fiber optic cable plants and communications systems, we've created two more "QuickStart Guides to Fiber Optic Testing." They are simple, step-by-step guides on how to test fiber optic cable plants, patchcords or single cables using insertion loss or OTDR techniques and optical power from transceivers. It's as straightforward as it can get - what equipment do you need, what are the procedures for testing, options in implementing the test, measurement errors and documenting the results.
It can't get much simpler.
Send anybody you know who needs to know about fiber optic testing here to learn how it's done in a few minutes.

Testing Fiber Optic Cable Plants And Patchcords  

Testing Fiber Optic Cable Plants With An OTDR  

Testing Optical Power In Communications Systems 


FOA Tech Topics - 

A Fiber Optic Tester In Your Pocket?  (See the video on Corning on YouTube )
Yes! The camera in your old cell phone is sensitive to infrared light - lots more than your eye - and can detect light in an optical fiber or from a transmitter.  Chris Hillyer,CFOT/CFOS/I, Master Instructor, Northern California Sound & Communication JATC brought this to our attention.
IR Viewer 850 nm  IR Viewer 1300 nm

If you have an old cell phone, try it. Our experience is that older cell phone cameras have better sensitivity at IR wavelengths than newer phones, so you may want to toss that old flip phone into the toolbox.


Product News

YOKOGAWA OTDR Has Extended range, High Resolution And Multitasking

Yokogawa OTDR

One OTDR manufacturer you don't hear as much about is YOKOGAWA (formerly ANDO) which is too bad - they make some of the best OTDRs, exemplified by this new model AQ7280. Need long range - how about 50dB. High resolution - 0.6m dead zone. Like touch screens, but for some functions want hard buttons, it's got that. Options for VFL, microscope, light source and power meter, etc. - it has that too.
But the unique aspect of the YOKOGAWA AQ7280 is it offers multitasking - you can let do a trace with long averages while you inspect connectors, make power readings, use the VFL or other functions.
More info on the YOKOGAWA AQ7280.

FOA thanks Yokogawa for a gift of an OTDR to use for R&D and teaching!

Have you read the FOA pages on cleaning?


 Digging Safely (Read the FOA Tech Topic)

There is a toll-free "call before you dig" number in the USA: 811

See for more information

The Common Ground Alliance has an excellent "Best Practices Guide" online

Fiber Optic Asset Protection Summit by the "811" group.

The US Department of Transportation has a website called "National Pipeline Mapping System" that allows one to search for buried pipelines.   


Employment/Job Listings

Send your job openings to info and we'll run them in all our social media.

Where Are The Jobs In Fiber Optics?

Fiber Optic Installation Banner

The FOA was chartered to "promote professionalism in fiber optics through education, certification and standards." Our focus on creating a professional workforce to properly design, install, maintain and repair communications network infrastructure has led us to work with groups in many different areas of technology that use fiber optics, way beyond the basic telecom applications that most of us think of first. FOA has probably worked with most of the potential applications of fiber optics, but we're always learning about new ones!
In addition, we get lots of calls and emails from our members looking for information about where the jobs are and how to train for them. FOA has created three ways to help you find jobs, train for them and apply for them.

Where Are The Jobs In Fiber Optics?
FOA has created a 20 minute YouTube video that talks about all the applications for fiber optics, what jobs are involved and the qualifications for the workers in the field. Besides telecom and the Internet, we cover wireless, cable TV, energy, LANs, security, etc. etc. etc. It's a quick way to get an overview of the fiber optic marketplace and we give you an idea of where the opportunities are today.

Watch the new FOA YouTube Video: Where Are The Jobs In Fiber Optics?

What Training Is Needed For The Jobs In Fiber Optics?
As you will learn from the video described above, the jobs in fiber optics are quite diverse. FOA has investigated these jobs to understand the needs of workers for those jobs and, when necessary, create curriculum and certifications to properly train workers. For example, the FOA FTTx certification was developed at the request of Verizon who needed specialized installers for their FiOS program. Now we are working with the industry on the OLAN (Optical LAN) program (see below).
We have summarized the jobs and required training in a new web page that has two uses - 1) If you have FOA certifications, what jobs are you specifically qualified for? - 2) If you are working in a specialized field or want to get a job in that area, what training and certifications will qualify you for those jobs?
What Training And Certifications Are Needed For Jobs In Fiber Optics? 

How To Find And Apply For Jobs In Fiber Optics
We get many questions from CFOTs, students at FOA-Approved schools and others contemplating getting into the fiber optic business regarding jobs in fiber optics - and how to find them - so we’ve created a new web page to share some information we've gathered about jobs in our industry. The information is designed to help you understand what jobs are available in fiber optics, how to find them and apply for them.
If you are looking for a job in fiber optics, here is the FOA's guide to jobs. 

We hope you find this useful. FOA tries to find new to increase the professionalism in our industry and helping qualified people find jobs is our highest priority - read the article below to see why! If you have feedback on how we can help you and our industry, contact us at

Join FOA on 
FOA on LinkedIn

A list of 10 ways to get your resume noticed, from Marketplace on NPR   

 Do listings in the FOA Newsletter and LinkedIn groups Work? Here's feedback:

"We did great!  We have over 15 interviews next week."

"Your newsletter generated a significant number of applicants and we have filled the position."



 FOA Logo Merchandise

New FOA Swag! Shirts, Caps, Stickers, Cups, etc.
FOA T Shirt
The FOA has created a store on offering lots of new logo merchandise. It has lots of versions of shirts and other merchandise with "FOA," "Fiber U," "Lennie Lightwave" designs and more so you should find something just for you! See FOA on Zazzle.

Your Name, CFOT® - It pays to advertise!

The FOA encourages CFOTs to use the logo on their business cards, letterhead, truck or van, etc. and provides logo files for that purpose. But we are also asked about how to use the CFOT or CFOS certifications. Easy, you can refer to yourself as "Your Name, CFOT" or "Your Name, CFOS/T" for example.

Feel free to use the logo and designations to promote your achievements and professionalism!

Contact FOA at to get logos in file format for your use.



Privacy Policy (for the EU GDPR): The FOA does not use cookies or any other web tricks to gather information on visitors to our website, nor do we allow commercial advertising. Our website hosts may gather traffic statistics for the visitors to our website and our online testing service, ClassMarker, maintains statistics of test results. We do not release or misuse any information on any of our members except we will confirm FOA certifications and Fiber U certificates of completion when requested by appropriate persons such as employers or personnel services.
Read the complete FOA Privacy Policy here.

To Contact The FOA:
The Fiber Optic Association Inc. (FOA) is the international professional association of fiber optics. FOA is chartered to promote fiber optics through education, certification and standards.

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The Fiber Optic Association or email <>

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