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April 2019

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FOA Newsletter - Features

In This Issue - (INDEX)

Click on "RETURN TO INDEX " after each section to return you to this INDEX so you can find things easier.


Greg Turton of Southern Fiberworx Named Georgia "ROCK STAR"
FOA Guide Adds And Updates More Pages
Dealing With High Fiber Count Cables
Which Is The Real California Palm Tree?
More New Connectors
Test Equipment And Inspection Microscopes for MPO Connectors
The Perils Of 2-Cable Referencing
FOA School Offers Toolkit With Online Training
Troubleshooting With A VFL:  Fibers Damaged In Splice Trays
Worth Reading
OTDR Test Summary from Pearson Technologies

FOA Certifications: 

CFOT Total


FOA Facts - about the organization

New @ FOA  
Fiber U - free online self-study courses
Publications: FOA Textbooks, NECA/FOA 301 Installation, eBooks
More "Quickstart Guides" - OTDRs
 videos: New FOA YouTube Videos
Online Reference Guide: Many new pages
Certification. Updated:  FOA OSP Certification
FOA Schools: New schools and programs
Q&A: What you are asking the FOA?
FOA Fiber FAQs Page
Product News - New stuff
Worth Reading: News from around the world
Download This - Good applications material online

Like Crossword Puzzles? Try These.

DIG SAFE - Call 811 before you dig!

JobsCurrent openings for Cable Techs, Fiber Splicers, etc. (More on the FOA Linked-In and other social media)
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.

Join The FOA eMail Newsletter List
Want to be notified when the FOA Newsletter is updated? Sign up for the FOA eMail Newsletter. You can also sign up from your cell phone: text "FOA" to 22828 (usual text msg charges apply)

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

The Archives: Past Issues.
Use these links to read past issues or use FOA's  Custom Search to look for specific topics on our website.
1/19, 2/19, 3/19, 4/19
1/18, 2/18, 3/18, 4/18, 5/18, 6/18, 7/18, 8/18, 9/18, 10/18, 12/18
1/17, 2/17, 3/17, 4/17, 5/17, 6/17, 7/17, 8/17, 9/17, 10/17, 11/17, 12/17 
1/16, 2/16, 3/16,  4/16, 5/166/167-8/16, 9/16, 10/16, 11/16, 12/16     
1/15, 2/15, 3/15, 4/15, 5/15, 6/15, 7/15, 8/15, 9/15 , 10/1511/15 , 12/15
1/14, 2/14, 3/14, 4/14, 5/14, 6/14, 7/14, 8/14, 9/14, 10/14, 11/14, 12/14 
1/132/13, 3/13, 4/13, 5/13, 6/13, 7/13, 8/13, 9/13, 10/13, 11/1312/13 
1/12 , 2/12, 3/12, 4/12, 6/12, 7/12, 8/12, 9/12, 10/12, 11/12, 12/12   
1/11 ,  2/11,  3/11,  4/11,  6/11, 7/11, 8/11,  9/11, 10/11, 11/11,  12/11,  
1/10 ,  2/10, 3/10,  4/10,   05/10,  07/10, 08/10,  09/10,  10/10, 11/10 
1/09 ,  2/09,  3/09, 04/09,  05/09,  07/09, 08/09, 09/09, 10/09, 11/09,  12/09
1/08 , 2/08, 3/08, 4/08, 5/08,  6/08, 7/08, 8/08, 09/0810/08, 11/08,  12/08 
12/07 , 11/07, 10/07, 09/07, 08/07, 07/07, 06/07, 05/07, 04/07, 03/07, 2/07, 1/07
12/06 , 11/06, 10/06, 09/06, 8/06, 7/06, 6/06, 5/06, 4/06, 3/06, 2/06, 1/06,
12/05 ,11/05, 10/05, 09/05, 08/05, 07/05, 6/05, 5/05, 4/05, 2/05, 01/05,
12/04 , 10/04, 9/04, 8/04, 7/04, 6/04, 5/04, 4/04, 3/04, 1/04,
12/03 , 11/03 10/03 9/03, 8/03, 7/03, 6/03, 3/03, 10/02 , 8/02, 5/02
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 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

FOA Videos on videos

FOA is a member of:

TIA Online
FTTH Council

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

Search the FOA Website With DuckDuckGo

Time To Renew Your FOA Certifications?
To keep your FOA certifications active, you need to renew them when they expire. Now we have a new more convenient way to renew - an online store at Paypal - where you can quickly and conveniently use your PayPal account or your credit card to renew your certifications.

You now renew with PayPal (or a credit card)
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PayPal is available worldwide

Greg Turton of Southern Fiberworx Named Georgia "ROCK STAR"

You probably remember our articles on Greg Turton of Southern Fiberworx. He contacted FOA about 5 years ago asking if a real estate developer in a small town in Georgia could build his own FTTH network. After talking to Greg long enough to understand his interest and experience in development, construction and technology (even holding patents on several inventions), we sent him off to several FOA schools to learn more about fiber optics. He also took his assistant David Herlovich and several other employees and decided to forge ahead.

By the time we visited Greg a year later, he had built and equipped a splicing trailer, rented and learned to use trenchers and directional boring machines, connected with ADTRAN to learn how to set up a head end, and was beginning to connect homes. His installers were the employees trained at an FOA school. He was delivering gigabit Internet to customers in Cordelle, GA that basically had typical rural services before - that is to say terrible service.

Today, Southern Fiberworx has 155 business customers and 550 homes on their network and is profitable! (That last point is important - Southern Fiberworx shows that an astute businessperson can build FTTH even in rural areas and make a profit. DIY (do-it-yourself) FTTH is real and a real business!

The success of Southern Fiberworx has not gone unnoticed. Recently Greg and his company received two awards. They were recognized as the SM Business of the Year by the Cordelle Chamber of Commerce. The state of Georgia Department of Economic Development recognized Southern Fiberworx as one of only four "Small Business ROCK STARS.

David Herlovich & Gov Brian Kemp
David Herlovich and Greg Turton of Southern Fiberworx and GA Governor Brian Kemp

The Georgia Department of Economic Development (GDEcD) and the Georgia Economic Developers Association (GEDA) team up every year to recognize the outstanding, unique and impactful small businesses in the state of Georgia. We salute the risks, innovations, outreach, and impact of our small businesses, as well as the reasons why these qualities abound in Georgia.

Georgia Economic Developers Association (GEDA) has done a nice film about Southern Fiberworx.

FOA Guide

FOA Guide Adds And Updates More Pages

 On Jargon, Restoration, Fiber Characterization And Management

The FOA Guide is a living thing, growing bigger and better continuously, updated for new technology and techniques, aimed at keeping the world up to date on fiber optics and cabling. In the last month alone, the Guide has added three new sections you should find interesting, informative and helpful and updated a couple more.

Fiber Optic Jargon - Illustrated

FOA has always believed that jargon is important - it's the language we use - and fiber optics has a lot of its own language. As you have probably noticed, Chapter 2 in all our textbooks is "Jargon." That chapter gives an introduction to the language and helps get the reader familiar with the terminology before they delve into the rest of the book. This month, we updated all the jargon pages to include dozens more photos and drawings - animations too - that make it even easier to understand fiber optic jargon. Take a look at Basic Fiber Optic Jargon, OSP Fiber Optic Jargon and Fiber Optic Jargon for managers.

Fiber Optic Restoration

All networks are susceptible to problems that affect communications. A consequence of fiber optic systems’ high bandwidth, long distance capability and security is the extreme dependence of users on the non-stop operation of these systems. They can transmit large amounts of data long distances with immunity from signal degradation and extremely high reliability, so these systems usually carry the most critical data. If something happens, it’s important to not panic. You should have a plan, components set aside for repair and knowledgeable people on stall or a contractor on call. When you design the network, restoration planning should be part of the design. If you did not do that, now is the time to do it before something happens. FOA has a new page on Restoration in the FOA Guide that provides advice for everyone - contractors/installers, network owners and managers - everybody who gets involved when the network goes down.

Fiber Characterization

As networks get faster and link spans get longer, fiber characterization becomes more important to he network owner and contractor/installer. Chromatic dispersion, the dispersion caused by light of different wavelengths, and polarization mode dispersion, caused by the polarization of the light in the fiber, become factors limiting the bandwidth capacity of fiber links. Pulse broadening due to dispersion and the variation of fiber attenuation with wavelength can become issues with DWDM. All these factors need testing on long distance networks to ensure proper link performance. Tests are performed on new installations to ensure the fiber being installed is capable of future upgrades. Older cable plants are tested to evaluate fibers for upgrades of legacy communications systems at slower speeds. We've created a certification program for fiber characterization, CFOS/FC, but not many FOA schools have the equipment to teach the course. In addition, we've had requests for a course for managers, not technicians, who don't need to know how to perform all the tests but do need to know what the problems are, what fiber links need testing and how to find competent contractors to do the work. 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.

Fiber Optic Testing

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.

Fiber Optics For Managers

In the FOA, as part of the fiber optic industry and especially in our role as educators, most of our focus has been training the designers and installers of fiber optic cable plants and networks. But what about the people for whom they work or build the networks? What do network managers, project managers, supervisors, network owners, IT personnel, facilities managers, network designers, estimators, inspectors, etc. need to know about fiber optics to ensure the success of their project?

FOA has been working with several groups to develop educational programs for managers. 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.

UPDATE: Dealing With High Fiber Count Cables - Share Your Experiences!

We ran this first in the March 2019 FOA Newsletter and asked for feedback. We have some feedback and have been talking to people in the industry also. We thought we'd share some of what we've been told and see if others agree. Feel free to comment!

UPDATE- April 2019:
High Fiber Count Cables may not be for everyone. Maybe only for a very few. A single cable that has as many fibers as 12-144 fiber cables (1728 fibers) in a cable with a diameter of only twice that of a conventional 144 fiber cable can present challenges.
  • First of all, the cost - it's high. You do not want to waste cable at this price. Engineering the cable length precisely will save lots of money.And it's worse for higher fiber counts.
  • Likewise, making mistakes when preparing the cable for termination can be expensive.
  • The cable may require special preparation procedures to separate fibers for termination. Most use new methods of identifying cables and bundles.
  • Besides skill, the tech working with high fiber count cables needs lots of patience.
  • Splicing multiple cables at a joint can get complicated keeping all fibers straight.
  • These cables will generally use 200 micron buffered fiber and often a flexible ribbon instead of a typical rigid ribbon structure to reduce fiber sizes. This may complicate splicing as the methodology to splice the flexible fibers and splice 200 micron fibers to regular 250 micron fibers is a work in progress.
  • Splicing 200 to 250 micron fibers may be easier with the flexible ribbon designs which make it easier to spread fibers to the same spacing.
  • We've heard the splicing time for flexible ribbons is about twice that of conventional rigid ribbons. So if you use that table below, you may need to double your ribbon splicing estimates when working with flexible ribbons.
Agree? Disagree? Comment?

ORIGINAL Article: March 2019

FOA has recently gotten several inquires about these new high fiber count cables - 1728, 3456 or even  6,912 fibers. Like this one from Prysmian with 1728 fibers:

Prysmian 1728 fibers

We've been looking for directions on how to deal with high fiber count cables. Several contractors tell us ribbon splicing is the way to go, and most of these cables now use a version of the new ribbon types that are flexible. We've  put together this table from some articles on splicing ribbons:
ribbon splicing

Is that realistic? We've heard the flexible ribbons may take twice as long as the conventional ribbons.

Here's links to some of the information we've been reading and watching online:
Corning sticks with solid ribbons in high density cables.
Corning ribbon splice closure for 1728 fibers.
Directions from Corning on ultra high-density cabinets
Designing a high fiber count cable with flexible ribbons - SEI.
Fujikura (Japan) Highest density Optical Fiber Cable.
OFS Presentation on 200micron buffer, bend insensitive, high fiber count cables.
Ribbonizing 250 micron loose tube fibers for splicing, AFL Fujikura. (video).  (Written instructions too.)
Splicing AFL "SpiderWeb ribbon cable.
Ribbonizing 250 micron loose tube fibers for splicing, Sumitomo. (video).  
Procedures for ribbonizing and de-ribbonizing fibers.  (Telonix)
Some things you need to know about splicing 200micron buffered fibers.

Some things you need to know about the new ribbon cables (Prysmian)
More coming next month!

We'd like more  information for a future story on these cables, new ribbon types and how installers deal with them. Share your experiences - email us at jim

There's more below....

.. plus some really interesting technical questions discussed in depth


The FOA 2018-19 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 (FAQ s = 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 including one about how fiber optic cable can catch fire from the signals it carries!

Which Is The Real California Palm Tree?

cell tower


palm tree cell tower
Anybody want to count the cables?

More New Connectors

We're seeing some interesting new connectors being introduced. 3M announced a multifiber array connectors using expanded beam technology and several new ideas of making a duplex connector smaller.

3M Expanded Beam Connector
3M Expanded Beam connector 3M

Details are sketchy but from the video on the 3M website, the connection is made by a small plastic fixture that is shown by the arrow in the top photo. The plastic seems to turn the beam 90 degrees so the connection is made when two pieces overlap., in the direction of the arrow in the lower photo. The connectors are hermaphroditic - that is two identical connectors can mate. There are models for singlemode and multimode fibers and you can stack the connection modules to handle up to 144 fibers. We understand this was not part of the 3M fiber optic product line recently acquired by Corning. 3M Expanded Beam Connector.  

For more information on expanded beam connectors, see the FOA Newsletter for October 2018 that discusses the R&M QXB, another multifiber expanded beam connector announced last Fall. 

In the FOA Newsletter for January 2018, we featured the SENKO CS connector, a miniature duplex connector using two 1.25mm ferrules, but much smaller than a duplex LC. The CS is sell on its way to becoming standardized with a FOCIS (fiber optic connector intermateabliity standard), but on the SENKO web page, there is another new connector, the SN, that makes the SC look huge! The big difference is the vertical format that allows stacking connectors very close. That can allow transceivers to have more channels, a big plus for data centers. Here is more information on the SENKO CS and SN connectors.


US Conec MXC and MDC Connectors
The R&M and 3M expanded beam multifiber connectors reminded us that US Conec introduced the
MXC connector over 5 years ago, using similar technology for up to 64 fibers per connector. The MXC is on the US Conec website, but seems to be aimed at board level connections, not far off its original purpose as a connector for silicon photonic circuits. But when we checked the US Conec website, there was a connector name we dis not recognize, the MDC. The MDC (below) is a vertical format duplex connector using 1.25mm ferrules that looks similar to the SENKO SN above. Here is information on the US Conec MDC duplex connector.

US Conec MDC connectorUS Conec

Its All About The Data Center
Just like the high fiber count cables discussed above, the CS, SN and MDC connectors are aimed at high density cabling and transceivers for data centers. All three are specified for the new QSFP-DD pluggable transceiver multi-source agreement.

Test Equipment And Inspection Microscopes for MPO Connectors

MPO cable test

The fiber optic industry has seen a number of recent introductions of inspection microscopes and test equipment for the MPO multifiber connector. It's about time, many people think, since the connector has been around for over a decade and has always been a problem to inspect and test. Earlier inspection microscopes with MPO adapters required manipulating the adapter to see individual fibers, but the new ones view more fibers and/or scan. EXFO's solution includes a source and can also do polarity checking, a nice feature. The test sets from Viavi and Fluke are multichannel OLTS, finally making MPO testing a reasonable exercise. Several vendors sell switches for OTDR testing also. We saw several others from unknown manufacturers we did not include. If you have suggestions for additional equipment, contact <jim@>.

Here's a rundown of what we found:

AFL FOCIS Lightning Multi-Fiber Connector Inspection System

AFL Multifiber Switch

AFL Multifiber Tracer (VFL)

EXFO ConnectorMax MPO Link Test Solution - polarity, continuity and connector testing

EXFO TK-Switch MPO and MTP Kit (12 fiber switch for SM MPOs with OTDR)

Fluke FI-3000 FiberInspector™ Pro MPO Inspection Camera

Fluke MultiFiber™ Pro Optical Power Meter and Fiber Test Kits

Kingfisher - Several microscopes and test kits

Viavi FiberChek Sidewinder

VIAVI SmartClass Fiber MPOLx - MPO Optical Loss Test Sets

If you have suggestions for additional equipment for this list, contact <jim@>.

The Perils Of 2-Cable Referencing

This month FOA received an inquiry about fluctuations in insertion loss testing. The installer was using a two cable reference method where you attach one reference cable to the source, another to the meter and connect them to set the "0dB" reference.

two cable reference
The problem with the two cable reference is the uncertainty added by including the connection between the two reference cables when setting the
"0dB" reference.Unless you carefully inspect and clean the two connectors and check the loss of that connection before setting the "0dB" reference, you add a large amount of uncertainty to measurements of loss. The best way to use a 2-cable reference is to set up the source and reference cable (with inspected and cleaned connectors), measure the output of the launch cable, attach the receive cable (with inspected and cleaned connectors) and measure the loss of the connection before setting the "0dB" reference. If the connection loss is not less than 0.5dB, you have connectors that should not be used for testing other cables. Find better reference cables.

Unfortunately, one reason the two cable reference is often used is the connectors on the cables or cable plant being tested are not compatible with the connectors on the test equipment, so you must use hybrid launch and receive cables. Then you can only reference the cable when connected to each other. In that case, you are stuck with the 2-cable reference and should expect higher measurement uncertainty. Experiments have shown that the uncertainty with a 1-cable reference is around +/-0.05dB while the 2-cable has an uncertainty of around +/-0.2 to 0.25dB caused by the mating connection between the two reference cables. Those experiments also showed the uncertainty of the 3-cable reference was not significantly larger than the 2-cable reference.

When possible, use a 1-cable reference. When you must use the 2- or 3-cable reference, inspect and clean all connectors carefully before making connections for the reference or test.

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

Troubleshooting With A VFLFibers Damaged In Splice Trays

Is this a trend? Twice in one week, we have inquiries from readers with problems and both were traced to fibers cracked when inserted in splice trays. The photo below shows one of them illuminated with a VFL. This was the same issue we found in the first field trial of a VFL more than 30 years ago that led to its popularity in field troubleshooting.

Broken fiber found with visual fault locator
Photo courtesy Alan Kojima.

Learn how to prevent damage to pipelines and cables 

Callbefore you dig

The CGA 811 Excavation Safety Conference & Expo is the premiere international event dedicated to providing educational content and resources to help protect buried assets. As the largest event in the underground damage prevention industry, the Conference draws nearly 1,700 participants and offers three full days of educational content, including CEUs for select educational sessions.

Register Here

Welcome To The New FOA Schools in Greece, Jackson, MS And Charlotte, NC

FOA is pleased to announce that School of Telecoms in Aigaleo, Greece (FOA school 768), Fiber Wizards (FOA school 380) and OnePath LLC in Charlotte, NC (FOA school 379) have joined the FOA as an approved schools offering FOA certification.

Want To Be A Guinea Pig And Save?
As part of our program to adhere to international standards for certifying bodies and to ensure FOA certified techs are up to date on the latest technologies and applications, FOA is also considering adding a short online course based on our annual "Fiber Update" as a future requirement for renewal. This course would cover new technology and applications that FOA thinks all technicians should be familiar with. Over the next year we will be testing this concept by offering it to selected individuals. You may be one of those selected! Watch your email for your renewal notice.

Another New Book On Tech (Warning: Shameless Self-promotion from your editor - J

Recruited by the CIA? Talk on tapping fiber classified? The stories are here.

Delusional Management book

As the author/editor of the FOA series of books, website and this newsletter, I'm kept very busy. But late last year I managed to finish my first book on high tech business called Delusional Management. It's part learning management by analyzing what others do wrong, part some history of the tech industry, including fiber optics and part memoir of 50 years in high tech. And some humor. Available on Amazon in paperback and Kindle. Jim Hayes

Worth Reading - News Summary

Singlemode Vs. Multimode Fiber: The Real Differences. Kudos to Jim Zimnicki of Belden who wrote this informative article. The cheer is because he used a diagram that did not show the fiber with the core sticking out of the cladding! Let's hope this is just the beginning of the industry showing fiber the right way!

Belden Fiber DrawingBelden

Taneytown (MD) officials consider limits on installation of small cell wireless technology

Guidelines for leasing dark fiber - Murphreesboro, TN. (With prices!)

The true cost of telco damages (e.g. dig-ups) (with checklist)

Ciena introduces 800G coherent over 1 wavelength.

Connected Real Estate Magazine.   (fiber backbones and DAS)

Watay Power Far north First Nation system - (from Bill graham) This Canadian project will bring electricity to 24 first Nation reserves including the farthest ones north, Bearskin Lake and Sachigo Lake. The towers will have  OPGW  and ADSS  for SCADA and other communications. all cables will contain 96 fiber.

The Joy of Standards - NYTimes - Life is a lot easier when you can plug into any socket.

Colorado DOT Installing Fiber Along Roadway Near Colorado Springs -(KKTV) - 17 miles buried along roadway for $2.5m - that's $147,058/mile - ~$28/foot or ~$91.40/meter.

What's Going On At Bell Labs: IP and Optical Networks We can approach the theoretical maximum information transfer rates, as defined as the Shannon Limit, discovered in 1948 by Claude Shannon, Bell Labs pioneer and “father of information theory”.

5 Best Practices for Utilizing GIS Data.   (White paper) American City & County

Installing OPGW - Quick Reference Guide (AFL).

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

Fiber by Susan crawford

Fiber: The Coming Tech Revolution―and Why America Might Miss It  by Susan Crawford, Yale University Press, available on Amazon. This is an extremely detailed history of how several American communities have built FTTH networks that have benefited their communities and incited incumbents to use every legal means to squash most of them. (See link above about municipal broadband being outlawed.) I should be required reading for any city officials who contemplate building their own FTTH networks. While it covers Chattanooga, TN, Wilson, NC and Santa Monica, CA well, it does not go into the many DIY groups that we've detailed here in the FOA newsletter like the ANZA, CA electrical co-op or Southern Fiberworx or the hundreds of smaller networks that have been built or are in the works. And don't expect a followup. The author is no longer interested in fiber. We met her at a meeting this month and she's off working on a new book on climate change.

Yokogawa Releases OTDR for Rapid Testing of PON Access Networks

Yokogawa AQ1210 OTDR
AMERSFOORT, THE NETHERLANDS — The new Yokogawa AQ1210 OTDR (optical-time domain reflectometer) only resembles the existing AQ1200 in appearance - internally it has been completely re-engineered to bring the features and user-friendly operation of the AQ7280 flagship OTDR to the installers and testers of passive optical networks (PON) and fibre to the antenna (FTTA).

PON is typically used throughout the world to provide optical fiber-based services to domestic and commercial customers. With 6 models offering 2 or 3 wavelengths, and the ability to test live fibre networks with high-port count splitters (up to 1:128), every user can find an AQ1210 model with the combination of wavelengths required to meet the testing needs of their local country or region.

For further information on the AQ1210 OTDR visit:

Pearson Technologies Issues OTDR Test Report Summary

Eric Pearson of Pearson Technologies,, FOA Founder and Master Instructor announced his latest publication, a two-part report titled Mastering Singlemode OTDR Testing. In the first part, Pearson  tested a two-segment fiber link with OTDRs from three manufacturers. The segment lengths were 103m and 6317m At 1310nm and 1550nm, Pearson Technologies compared repeatability, accuracy and agreement of three characteristics. The characteristics were length, connector loss, attenuation rate.
In the second part, with the same OTDRs used in the first part, Pearson Technologies determined the minimum segment length, above which singlemode attenuation rate measurements become accurate.

A summary of the results of the first part follows.

Length Repeatability
All three OTDRs exhibited excellent repeatability at both short and long lengths and at both wavelengths. The largest difference between repeated measurements, 0.08 m (3.14”), was so small that field problems would be unlikely. In addition, comparisons of length measurements made with different OTDRs at different times should not result in incorrect interpretations.

Connector Loss Repeatability
All three OTDRs exhibited excellent connector loss repeatability at both wavelengths. The largest average difference between repeated measurements, 0.039 dB, was so small that field problems would be unlikely. In addition, comparisons of connector loss measurements made with different OTDRs at different times should not result in incorrect interpretations.

Attenuation Rate Repeatability
At 6317m, all three OTDRs exhibited excellent attenuation rate repeatability at both wavelengths. Maximum difference between repeated measurements was less than 0.001 dB/km. In addition, comparisons of attenuation rate measurements made with different OTDRs at different times should not result in incorrect interpretations.
At 103m, all three OTDRs exhibited poor attenuation rate repeatability. Part 2 of the report presents Pearson Technologies’ understanding of the cause of this poor repeatability.

Length Accuracy
At both 103m and 6317m, all three OTDRs exhibited acceptable length accuracy at both wavelengths. The largest difference between software and manual measurements was 0.24m (9.8“). This value is not considered likely to cause problems in locating a defect or event.

Connector Loss Accuracy
After elimination of obvious errors, all three OTDRs exhibited acceptable connection loss accuracy at both wavelengths. The largest difference between software and manual measurements was 0.014 dB. This difference is small enough that it is unlikely to result in errors of interpretation.

Attenuation Rate Accuracy
At 6317m, the attenuation rate accuracy was excellent at both wavelengths. However, at 100m, accuracy was absent at both wavelengths. The second part of this report presents an analysis of the causes of such inaccuracy of singlemode attenuation rates for short length segments.

Software Length Agreement
At both 103m and 6317m and at both wavelengths, all three OTDRs exhibited acceptable agreement between manual and software length measurements. Using any of the three OTDRs to find a defect at either distance allows the installer to get close enough to the location to find the problem.

Software Connector Loss Agreement
At both wavelengths, agreement of manual and software connection loss was not as good as agreement between of other characteristics. This reduced level of agreement may result in difficulty of interpretation of loss increase if multiple measurements are made with different OTDRs at different times.

Software Attenuation Rate Agreement
At both wavelengths and at 6317m, attenuation rate agreement was good at 1310 nm and excellent at 1550 nm. However, at 100m and at both wavelengths, attenuation rate agreement was poor and unacceptable. These results indicate that all three OTDR were unable to produce accurate attenuation rates measurements of short singlemode segments.

While determining agreement between reflectance measurements made on the three OTDRs was not an objective, the study demonstrated obvious disagreement, indicated by low to high differences of 21.9 dB at 1310nmand 13.6 dB at 1550nm. In addition, all traces demonstrated violation of the ANSI/EIA/TIA-455-8- 2000 requirement that the reflectance not indicate detector saturation. Such saturation indicates the reflectance values are lower/better than reality. As such, all three OTDRs indicated inaccurate reflectance results.

Automatic Software Analysis Errors
The automatic trace analysis software of all three OTDRs exhibited a significant incidence of errors. A consequence of these errors is that the OTDR operator cannot blindly accept the values in the event table. Some of these results will be incorrect.

# Parameters Tested
# Parameters In Error
% In Error

Based on more than 1,584 OTDR tests, Mastering Singlemode OTDR Testing includes 92 pages, 13 figures, and 85 tables.

After May 6, 2019, the report will be available from Amazon.

Optical Loss: Are You Positive It’s Positive?

A recent post on a company’s blog and article on the CI&M website discussed the topic of the polarity (meaning “+” or “-“ numbers) of measurements of optical loss, claiming loss was a positive number. The implication was that some people failed fourth grade math and did not understand positive and negative numbers. The claim is that insertion loss is always a positive number. Is that right?

Well the real problem is that to understand this you need to understand logarithms and that’s Algebra II*, way beyond fourth grade addition and subtraction. You see dB is defined as a logarithmic function:

dB equation

With logarithms, if the ratio of measured power to reference power is greater than 1, e.g. measured power is more than reference power, the log is positive. If the ratio of measured power to reference power is less than 1, e.g. measured power is more than reference power, the log is negative. If the ratio is 1, the log is 0.

Since the logarithm for optical power ratio is base 10 and then multiplied by 10, each change of 10 in the ratio of the measured and reference power becomes a change of 10dB. E.g. +10 dB is a factor of 10 (10 times log10 10 which is 1), +20dB is a factor of 100  (10 times log10 100 which is 2), +30dB a factor of 1000  (10 times log10 1000 which is 3)and so on. Negative dB means division, so -10 dB means a factor of 1/10th  (10 times log10 0.1 which is -1), -20dB a factor of 1/100th  (10 times log10 0.01 which is -2) and so on. 0 dB means the measured power to reference power ratio is 1 – they are equal.

Let’s try a graphic explanation of this equation. Take a look at this “semi-log” graph (logarithmic on the x axis and linear on the y axis) of dBm vs optical power in the range commonly used for fiber optics and calculated with our equation above. Remember 0 dBm means all power is referenced to 1 milliwatt optical power.

dB to watts

As you move to the right, power increases and the value in dBm gets more positive – that would be gain. So from 1mw to 10mw, we see a gain from 0dBm to +10dBm or 10dB, a positive change.

As you move to the left, to lower optical power, as would be loss, the dBm value gets more negative. From 1mw to 100microwatts (that’s 1/10mw), we go from 0dBm to -10dBm, or -10dB; that negative change indicating a loss of 10dB.

That shows gain is positive dB and loss is negative dB. Now we’re getting to the fourth grade math.*

How about an example? Let’s say we decide to test a singlemode cable plant. We start with a laser source and launch cable which we measure our reference level for loss with a power meter to have an output of 0dBm. That’s 1 milliwatt of power, about the normal output of a fiber optic laser. After we attach the cable plant to test and a receive cable to our power meter, we measure 3dB loss.

What power did we measure? The power must be lower, of course, since we have loss, and 3dB is approximately a factor of 2, so the power the meter measured is 1mw divided by 2 = 1/2milliwatt or 0.5mw. Since our power meter is measuring in dBm, it will read minus 3dBm (-3 dBm), since lower optical power is always more negative. If it read +3dBm, the power measured would be 2mw and that would be a gain from our reference (0dBm) which we know is incorrect – passive cable plants are not fiber amplifiers.

Here is the graphical version of this loss test:

 dB loss or gain

And then there is this short movie on the FOA Guide page explaining dB showing how a power meter shows loss when a cable is stressed to induce loss:

dB on a power meter

As the fiber is stressed, inducing loss, the power level goes from -20.0 dBm to --22.3 dBm.That's a more negative number.

No question – loss means a more negative power reading in dB and a negative number in dB indicates loss.**

But if you are a manufacturer of fiber optic test instruments that offers optical power meters and sources to test loss, why would this confuse you? 

Perhaps we should blame accounting.

Suppose you have a company that has $1million in sales and $900,000 in expenses. What’s the profit? It’s $1,000,000 - $900,000 = $100,000. That’s a profit, right?

But suppose your company has $1million in sales and $1,100,000 in expenses. What’s the bottom line? It’s $1,000,000 - $1,100,000 =  - $100,000. Wait a minute, that is a negative number – that’s not a profit, it’s a loss.

So in accounting, profits are positive numbers and losses are negative numbers when we do the math, but when we talk about loss, we don’t say we have a loss of “-$100,000,” we just have we have a loss of $100,000. Then we’ll put that number in parentheses when we publish our P&L like this ($100,000) and hope it doesn’t get noticed by investors, but you know it will.

Loss and gain in fiber optic measurements are similar. If you are using a separate source and power meter, loss will be a negative number and gain will be a positive number. But because of convention, we sometimes drop the signs when we report the values because loss always means the optical power measurement was negative and gain means the optical power measurement was positive. But maybe that’s not what the convention has evolved to.

Optical loss test sets (OLTS) aren’t designed to measure and display optical power, just loss. The actual power measured is lost in the algorithms used for calculating loss based on the “0dB” reference power and the measured loss. Long ago, most OLTS measured loss and displayed it as a negative number, but some companies who got into the fiber optic test equipment business from other test businesses arbitrarily decided to display loss as a positive number, and today most OLTS do show loss as a positive number. But when the instrument sees a gain, which it can do if improperly used, it therefore displays a negative number, which can be very confusing to a trained fiber tech who understands fiber optic power and loss measurements.

OTDRs do the same thing. I looked at traces from a half-dozen OTDRs and all showed loss as a positive number and gain as a negative number. And yes, when you have a gainer in one direction, they show it as a negative number. Telling them that is wrong will fall on deaf ears, I’m afraid.

The same article/blog post goes on to discuss optical return loss and reflectance, which has similar issues but they get it more or less right, which is confusing. Why can they understand that more negative numbers for reflectance means lower power in the reflectance but claim the opposite for insertion loss?

The “less right” is that with most OTDRs reflectance of an event and optical return loss (ORL) are not the same thing. ORL is the summation of all reflectance events and fiber backscatter from the entire length of fiber.

And, please, please stop saying “back reflection;” a reflection always goes back toward the source so the term is redundant and was dropped from fiber optics years ago.

*So the problem is not simply fourth grade math, it also involves a bit of convention and tradition and marketing. And it requires understanding logarithms that create the negative number of loss. That’s more like Algebra II or 7th grade math, and here is a good tutorial from Kahn Academy on that:

And more basic, here is a tutorial on adding and subtracting negative numbers

** If you want to calculate this yourself, FOA has a XLS spreadsheet you can download that will calculate the equations for optical power for you.

The FOA has an explanation of dB on our online Guide and a couple of graphics that illustrate what happens with loss.

Blasting Near Fiber Optic Cables

Last month we ran a Q&A question about blasting near fiber optic cables. Bill Graham, FOA Board Member and long-time instructor in Canada, tells us that he suggests a more conservative approach. This is what he has taught in his classes:

Blasting and Fiber Optic Cables

Two situations:
1.)    Aerial on poles or towers
2.)    Buried in ground


Blasting near fiber optic cables
Blasting close to poles with fiber optic cables can depend on the soil between the blasting area and the pole.  For example:  In parts of Ontario there are large areas of solid granite. The pole is generally bracketed to the rock. (Some areas have started drilling the rock) there is a solid connection from the blast hole to the pole, up the pole onto the bracket and to the Fiber Optic cable, which they seem to forget is glass.

Blasting near fiber optic cables

We recommend the following:
1.)    Cover the aerial cable with Big O (4” perforated drain pipe slit along the length) as shown in the photo above. This protects only from flying rock.
2.)    Removing the cable from the pole clamp and hanging it from the bracket with a  Bungie strap.

Blasting near fiber optic cables

Blasting locations are carefully engineered… however, if the crew wants to get home early on Friday and they double up on the blasting the damage risk increases substantially. ( The red cups in the photo are blast holes.) Most companies are wary  enough not to guarantee “no glass damage”. This area is almost all solid granite.

Cables Buried Underground:
Regardless of Kinder Morgan’s recommendation, I suggest 5-6 meters separation is not adequate and  should be at least 12 to 15 meters.

Resource For Small, Private FTTH Systems

Phil Trubey worked with his homeowners association to research and develop a FTTH network. In doing this, he researched FTTH thoroughly (including FOA). He's created a website to share what he learned. FTTH.Build is an informational site for HOAs and small communities on how to build your own Fiber To The Home gigabit Internet network.

This web site is to help Home Owners Associations and other small communities who are looking to build their own fiber optic network to provision gigabit Internet for their residents. It assumes that you are on your own, and no telecom carrier is interested is building out a fiber network for your area. Methods described here are applicable to communities ranging in size from a couple of hundred residents to 20,000 or more residents.


TIA Fiber Optic Tech Consortium Has New Website


The TIA FOTC, a group of TIA companies that promote fiber use, has a new website with lots of information on the organization, it's webinars and white papers. It also has a section on member news that includes new products and applications.

Updated FOA Certifications

  We continue to expand our certification offerings, adding "Fiber For Wireless" last year, and fine-tuning our current offerings to keep up with the changes in fiber optic technology and applications. In the last year we've updated our CFOT, CPCT and CFOS/O certification programs and their FOA references online and in textbooks.

The CFOT fiber certification update includes adding more information about new technology and products like SOCs (splice-on connectors), microcables, as well as expanding the information on OSP and premises applications. The CPCT premises cable program has been updated to cover the new technology in areas like passive OLANs and data centers.

The biggest change in FOA programs was to the CFOS/O Outside Plant (OSP) Specialist program. We were asked to cover more about OSP construction so we integrated the material from the FOA OSP Construction Guide written by FOA Master Instructor Joe Botha into the course. To make room for the new material, we changed the prerequisites of the course to require a CFOT, instead of covering basic fiber tech in the OSP course.

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.

New Section Of The FOA Guide - The FOA Guide to OSP Construction

FOA has created a new section of the FOA Guide on OSP Construction. We've expanded some sections to include more on cable pulling, blowing and aerial construction with lashed and ADSS cables. The FOA has extensive material available in our textbooks and online FOA Guide on what is involved in the fiber installation process (cable installation, preparation, splicing, termination and testing), so consider this the textbook for the construction processes that occur before the typical FOA CFOT-certified techs begin their work.

Included in this new Guide is comprehensive information on new techniques like air-blown cables using microcables and microducts. It also covers aerial cable installation more thoroughly than is typically found in websites or literature.

The audience for this new section of the FOA Guide includes the management of organizations owning or installing fiber optic cable plants, designers or estimators of the cable plant, as well as the actual CFOT certified techs doing the installation work. It is intended to provide background information on the entire project and in conjunction with the other FOA information on basic fiber, OSP fiber, design and testing, provide complete information on all stages of a fiber optic communications project.

The FOA Guide to OSP Construction

Also new - FOA Guide section on inspecting and cleaning connectors.

New Free Fiber U Course On OSP Construction 

Now that we have the FOA Guide on OSP Construction, we can do a free Fiber U online course on the subject. The new Fiber U Course On OSP Construction includes a review of fiber optic technology for those just getting started or looking for an update, a lesson on project preparation, then covers underground construction, underground cable installation, aerial cable construction and installation, then leads you to the next steps in OSP construction, splicing, termination and testing.

This Fiber U course is aimed at managers of fiber optic projects, either with the network owner or the contractor building it, want to know how this construction is done and how it needs to be designed, estimated and construction. It is also appropriate for installers and contractors who are involved in the construction process also.

Take the free
Fiber U Course On OSP Construction here.

As we researched products and installation practices for the new OSP Construction sections, we came across some interesting products and services. See
OSP Construction below.

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.

Investigators Eye Fiber Optic Work in Deadly Wisconsin Gas Explosion

Firefighter killed, nine injured, and three buildings destroyed in downtown Sun Prairie, Wis.

A hole punched into a 4-in.-dia gas pipeline during fiber-optic line laying is blamed for an explosion that killed a 34-year-old fire captain and injured nine other people, including four firefighters, in downtown Sun Prairie, Wis., on July 10. The injured were treated at nearby hospitals and have since been released. The blast destroyed three buildings, including the Barr House, a tavern at 100 Main St. that was owned by the deceased fire captain, Cory Barr.

Sun Prairie Fire Chief Chris Garrison said at a news conference that after the leak was initially reported at 6:20 PM CDT, first responders established a 300-ft-dia "hot zone" in the area and evacuated about 65 people before the explosion occurred. "The rapid response of firefighters, EMS and police saved a lot of lives," Garrison said. "This could have been a lot more tragic than it was."

The owner of the fiber-optics network is Verizon Wireless, which confirmed in a statement that it had contracted with Bear Communications "to provide a fiber backhaul for our networks." It added that no Verizon employees were present at the job site. "Verizon does contract with local providers in various markets to provide fiber backhaul for our networks," the Verizon statement said. "While we have not been contacted about the investigation, both we and Bear are prepared to work with law enforcement, public safety and public officials as they investigate this tragic situation."

Read the story in ENR. And the final report by the NTSB details the mistakes made by the contractor.

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 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?

FOA Facts

FOA is a non-profit professional society whose members are all certified 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 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.

Find us on Facebook  FOA on LinkedIn  videos 
Pinterest  Twitter

New From FOA

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

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 Consultants

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 more than 15 years now. Electrical contractors do lots of fiber work and this column has covered some toics they are interested in including installation processes, network design, fiber applications and in the last year, 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.

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.

Self -Study in Fiber Optics
FOA iPad AppOur first app is a self-study version of the FOA Reference Guide to Fiber Optics. The FOA APP builds on the FOA basic fiber optic textbook to create an interactive learning environment that builds on the iBook electronic version of the book to add a guide to use for self-study and real-time testing that provides feedback on what you have learned and correct answers to questions answered incorrectly.
The FOA APP is priced at only $9.99, same as the iBook, so the self-study program is free. Download it from the Apple APP Store with your iPad or iTunes.



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 Guide

What's New  in the FOA Online Fiber Optic Reference 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. Go to the FOA Guide Table of Contents to see the latest updates - look for New.

Search the FOA Newsletter, Online Guide and website with DuckDuckGo.
Go to  The FOA Online Fiber Optic Reference Guide.


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.

Real Questions From FOA Newsletter Readers

Communications Cables on Utiity Poles
Is there a standard that service providers such as ISP, FTTH or cable TV should follow when installing their cables on existing electric poles. For necessary clearances etc. ?
A: The location of comms cables is in the “Communications Space.” At the top of the pole is the “Supply Space” for power conductors and between the two is a “Safety Zone Space.” It is There are guidelines of various types, mostly referring to NESC Rule 235. One of the best documents on this is from Nashville Electrical Service.  This presentation from Finley Engineering offers a good summary.

"Snowshoes" On Aerial Cable
For overhead installation, can snow shoes, or other service loop devices, hold two separate cables? 
Snowshoes are sized for different cable sizes and types. Some snowshoes are big enough for several cables, that’s no problems.

Fiber and Power Sharing Conduit
We are working on a project that has miles of underground 7 cell innerduct conduit with existing fiber already running through one of the cells. Is it possible to run electrical conductors through the 2 of the other cells? The conductors would be no larger than 1/0 AWG at 480V or 600V. Both the fiber and the electrical are being installed for the same use.
A:We questioned several people in the electrical side that also do fiber work. The opinion is that the electrical may use the other ducts. If the fiber cable has conductive members, e.g. armor, it must be properly grounded. And any cables spliced in manholes need separation and marking. The concern is over what happens with a dig up, but as long as the electrical is turned off before restoration begins, there should be no problem. If you need a reference, The National Electrical Safety Code (NESC) or ANSI Standard C2 is a United States standard of the safe installation, operation, and maintenance of electric power and communication utility systems including power substations, power and communication overhead lines, and power and communication underground lines.


Fan-Out Kits Needed?

Q:I’m working on some MM fiber and am unsure if I need a fan out kit. Is there a way I can tell if I do?

A: Is it 250 micron or 900 micron buffer? Splicing or termination? Loose tube or tight buffer cable? Generally loose tube cable with 250 micron fiber needs no fan out kit for splicing - tubes go to splice tray and bare fibers are protected in the tray - but probably needs it to terminate if the fibers are exposed, for eample with SOCs - splice on connectors. Tight buffer - 900 micron fiber - does not need fan out kits.

APC COnnectors

Q: We've got a discussion going in our department about whether an APC connection is required at both ends of an electronics link or just in one spot when trying to control reflection for broadcast equipment.  Thoughts/advice?
A: It seems you could use APCs on the transmit end to prevent reflectance bothering the laser source, but it would get reflectance from the receiver end, probably not an issue unless you are on short links, like in a data center where the far end reflectance would not be attenuated substantially.  If you put the APC at the receiver end, you would still have problems with reflectance at the transmitter end. Perhaps the biggest problem is managing to keep patchcords straight. We’d vote for the simple solution, all APCs, which is what many people are doing today. Alternatively, use the best UPC connectors which have only about 10dB worse performance as long as they are kept clean.

Test Multimode At 1310nm
Can I test multimode over 1310 wavelength?
A: Certainly you can, but why? In fact, multimode fiber has been tested at both 850 nm and 1300 nm for most of its history. Some standards still call for testing at both wavelengths.
When network speeds were 100Mb/s or less, sources were LEDs at 850nm used for shorter links - a few hundred meters - and LEDs at 1300nm were used for longer wavelengths, up to 2km for networks like Ethernet, FDDI and ESCON.
When Ethernet jumped to 1 gigabit/s, LEDs could not be used; they were limited to ~200 Mb/s. The new fast VCSEL sources (vertical cavity surface-emitting lasers) were adopted for most links. Some networks still offered a 1300 nm option using 1310 nm Fabry-Perot lasers since VCSELs are limited to about 950nm wavelength max. The 1310 lasers available were generally pigtailed with singlemode fiber and required some special launch cables to prevent modal problems, and even though they offered longer range, they were not really cheaper than using singlemode fiber and never gained much popularity. (See Specifications for fiber optic links and systems, including FTTx)
So multimode fiber became almost exclusively used at 850nm. In standards committees we discussed dropping the requirement for testing at 1300nm, but some argued that since the fiber is more sensitive to stress/bending losses at 1300nm, testing at 1300nm provided information on the stress in the fiber. Once multimode fiber became almost exclusively bend-insensitive fiber, that argument lost validity.
While some standards still call for 1300nm testing and many test sets offer 850nm and 1300nm LED sources, it’s probably not worth the time.

Fiber Backscatter Coefficient
I was wondering if you have an idea of how accurate the numbers from a fiber datasheet are for the stated backscatter coefficient of the fiber.  When looking at these numbers reported on datasheets, they are nice round numbers like -77dB, -82dB etc., which tells me that those aren’t actual measurements.  They are more ballpark values.  Would you happen to know roughly what sort of accuracy those would have for a given length of fiber?
A: We believe is the number is an average from some tests done whenever the fiber was designed and first manufactured and is +/- several dB. Remember it’s not a guaranteed spec like attenuation coefficient which they do measure.
Remember it is dependent on the pulse width. Corning in the SMF-28 data sheet quotes the numbers you have for a 1ns pulse width. ( You can probably surmise that 1 ns pulse is hardly a square wave and there will be lots of variations in the integrated power in a 1ns pulse created by different instruments. And who knows how you relate that power to a 5, 10, 20 ns or whatever pulse.
This paper by Corning talks about reflectance and backscatter and has some interesting points: The key is backscatter is inversely proportional to mode field diameter, so small changes in fiber diameter can cause changes in backscatter - and MFD variations of several percent are possible.

For overhead installation, can snow shoes, or other service loop devices, hold two separate cables?  I imagine the bend radius is a factor.
A: Snowshoes come in many sizes and are often sized for holding several cables, for example loops around dome splice closures with 2 cables being spliced.

Mismatched Fiber Losses
Q: If I have 50 micron test leads for my OLTS and I used them to test a 62.5 micron fiber link what can I expect in terms of results?  Will the 50 micron leads give me (generally) higher or lower loss values?
A: Yes, you will see higher and or lower loss depending on which way you test. See this page in the FOA Guide on Mismatched Fibers.

Pull ADSS Cable In Ducts Underground?
Q: Our city is installing a 1.5 mile run, mostly aerial and we want to use ADSS cable. There are two or three road crossings where we want to go underground in conduit installed by directional boring. Can the ADSS cable be dead-ended, brought to the ground, figure-8ed and pulled through conduit then continue the aerial installation?
A: The answer is yes this is not an issue and is done all the time. It is standard procedure. (Thanks to Pat Dobbins, FOA, the expert on ADSS cables.)

Q: I recently read an article you wrote in April of last year about micro trenching..Currently, I am employed with an underground construction company. Something we have never been involved with is micro trenching and would like to possibly get some equipment and training scheduled in the near future. In saying that, it has seemed to be almost impossible to find numbers on the price per foot. Essentially, I am asking if you have any resources to some up with those numbers or models to maybe use for pricing purposes.

A: Microtrenching is becoming another tool that contractors are adopting because like directional boring is is less disruptive than regular underground construction. I’m working with one group that’s using microtrenching in CA cities, installing microducts and a 288 fiber   about the size of a #2 pencil. Cost is difficult to generalize other than “more than aerial and less than trenching.” Cost is very dependent on  where you are working and what the local geography looks like. We know one contractor who claimed to do 5 miles a day in rural Washington at costs near that of aerial. It’s especially good in areas with lots of base stone where trenching or boring is near impossible or cluttered utilities downtown.

Here are a couple of pages on the FOA website about microtrenching:
Outside Plant Fiber Optic Cable Plant Construction
Underground Cable Construction

Ditch Witch sells equipment for trenching and trains users. Condux has the equipment for blown cable and offers training several times a year.

Old Multimode Fiber
We have old multimode fiber and we are still connecting more equipment to it over greater distances and need some way to insure the equipment will work.
A: I do not know of any simple formula for figuring this out. Last time I remember such a formula from around 2000 done for Gigabit Ethernet with VCSELs and the equation reminded me of the quantum mechanics course I took in physics. The problem is you have two bandwidth factors, modal dispersion and chromatic dispersion. Modal dispersion is highly dependent on mode fill, e.g. the metric “encircled flux” was developed to define the mode fill of multimode fiber with VCSEL sources for simulations to estimate bandwidth. Chromatic dispersion is dependent on the fiber spec and the spectral width of the source which is better with lasers and LEDs.

What generally happens is the standards group developing the network standard, especially IEEE 802.3 for Ethernet, runs the numbers and specifies a maximum distance for the particular network and its speed. FOA has a table of these specs here: Specifications for fiber optic links and systems, including FTTx

Can A Fiber Optic Cable
Catch "Fire"
Q: While working on a cut-over of a dwdm circuit something has happened that I am now looking for an explanation. A transmission fiber emitted "fire" on that same fiber! We did not see any optical light we saw fire. About 5 cm of fiber burned and remained smoke. What phenomenon occurred? Are the dwdm amplifiers so powerful enough to generate fire? Unfortunately I could not get into the station to take the model of the equipment.
A: We’ve heard of high power WDM systems exploding dirt of the endface of fiber connectors and damaging them, but this is a new one. We contacted several technical people in fiber companies and found that this can happen if there was a crack in the fiber in the cable near the connector or lots of reflection perhaps caused by a very dirty connector that allowed the very high power to heat the cable enough for combustion. DWDM with many multiplexed signals and a fiber amplifier creates a lot of power confined to a very small core of the singlemode fiber. That power can ignite the acrylate coating on the fiber.

Installing ADSS Cable Underground
I'm installing an aerial run of ADSS cable and wonder if I can pull the cable under roads in duct installed by directional boring without splicing when I need to go underground.
A: Yes you can pull ADSS cable in ducts installed by directional boring without splicing. Just install the ADSS cable link to the pole where you need to go underground and "dead end" it at that pole. Drop the cable down, "figure-8" the cable to prepare for the pull, then pull the cable in the duct. If you go aerial on the other side, just continue the ADSS installation procedures.

Reflective Events Causing Transmission Problems
I have a technical question about reflective events. I recently assisted to troubleshoot an intermittent SM fiber link for a customer. The cable was dug up a few years ago and a fiber contractor has (fusion spiced) a different chunk of cable into the link to repair it. When troubleshooting the link, I checked the cable with the otdr. I found that each of the 12 fibers had a reflective event at the fusion splice. This was only at the splice tube closest to me. The other fusion splices in the other tube were virtually invisible (as they should be). I'm a little puzzled as to why there are reflections at the fusion splices. I did a little research, but couldn't come up with a good answer as to what is a possible cause of the reflections. (The OTDR also showed a lot of ghosting on every fiber tested) (in some cases it recorded over 40 ghost events) Although I haven't been able to confirm that there is high Bit error rate due to the transceiver not providing these statistics, (except for 3 out of 10 pings fail) I am suspecting that High reflectance is possibly the cause of their unreliable fiber link.
A: Reflectance is a big problem in SM links, especially short links. If you are seeing lots of ghosts, I suspect the link is very short. Fusion splices can have reflectance if the splicer is improperly set and the fusion is incomplete or has bubbles. Those splices should have not only have reflectance but higher loss. The solution is to open up the closure, use a VFL to find the reflective events and redo the splices.

Blasting Near Fiber Optic Cables
We have a project where blasting is planned near fiber optic cables. We find no standards for this. Is it safe for the fiber or should we treat it like other utilities like gas and water?
A: FOA recommends considering fiber optic cables to be similar to gas lines when blasting nearby. We know of no standards for this but there are some descriptions of projects requiring blasting near fiber optic cable installations. Here is a pipeline company's guidelines for blasting. The guidelines seems to focus on staying 5m from the fiber optic cable and using careful blasting techniques.

Cleaning Connector Protective Caps
How do you clean LC Fiber Optic end caps (the cap that covers the cleaned fiber cable)? Is there a tool for that?
A: We assume you are talking about the small plastic protective caps on the connector ferrule. There is a joke in the industry that goes “there’s a reason they call them "dust caps’” they’re often full of dust.” The problem is these are plastic molded parts that are made by the billions for various purposes - some just fit fiber optic connectors. They come out of the molding machine and are dumped in barrels. No provision is made to keep them clean, plus they will have some mold release chemicals inside them that can attract or hold dust. Even static electricity is a problem.
We know no way to clean them nor to keep them clean. We recommend using them to protect the connector ferrule - in fact we’re trying to get people to call them “protective caps” - but after they are removed and before use (connecting to another cable or a transceiver or testing them) they need inspection and cleaning.
See these pages in the FOA Guide: Microscope Inspection And Cleaning of Fiber Optic Connectors  Cleaning Fiber Optic Connections

Directional Splice Loss
Q: I have a customer that is splicing a fiber distribution hub to their fiber plant.  The fiber distribution hub utilizes 100FT long fiber stubs of SMF G.657.A1 and the fiber plant uses SMF G.654.D.  The project has a contract fusion splice passing spec of 0.2dB loss, averaged bi-directional and also a one-way <0.3dB loss (either direction) specification; using an OTDR for measurements.
From my research, if the splices OTDR’s test results for the 2 directions are -0.2dB / +0.6 (average of +0.2), the network is not actually seeing a +0.6dB loss; but this is how the OTDR interprets the backscatter information… the OTDR being somewhat confused due to the bend insensitive fiber characteristics.
A: Correct - the directional differences are due to the mode field diameter variations in the two fibers.  G.654 is a large MFD fiber, ~12.5microns, compared to ~9 microns for G.657.A fiber. The OTDR measures based on backscatter which will be very different for the two fibers.

Markers For Underground Fiber Optic Cables
I have a general question about above ground markers for fiber optic cable in conduit.  Is there a recommended spacing for the markers?  Is there a standard to reference for this?
A: We asked some people who make them and they said the guideline is “line of sight.”  The rules for markers are mainly what information needs to be on them. Of course we also recommend adding marker tape about a foot above the conduit. I was curious if there were any legal issues and I found this interesting page from Cornell Law School:
So I might  add to line of sight any crossings of roadways, rail ways and some markers for bridge crossings.
We have a new section on the FOA Guide: Outside Plant Fiber Optic Cable Plant Construction that may be useful.

Reflectance And Return Loss
Q: Help me understand measuring reflection little better. Why do we consider -55dB to be a better reading than, say, -25dB? If reflection and return loss are inverse readings and we had a 55dB return loss, would that positive reading for return loss be considered good?
A: Reflectance is measured as the ratio of reflected to incoming signal at a connection. The confusion comes because reflectance and return loss are inverse readings. Consider this:
If we have 1/1000 of the light reflected, the reflectance would be -30 dB (1/1000 = -30 dB) but the return loss would be 30dB since it is defined as 1000/1, the inverse, and is described as +30 dB.
Likewise, an APC connector would have a reflectance of -50 dB or a return loss of 50 dB.
However, return loss as tested by all OTDRs is not be the reflection from a single event but the total of all reflectance events plus total backscatter from the length of fiber being tested in the trace.
This is where most people are confused and misuse the terms.

Older questions are now available here on the FOA Guide.


Worth Reading or Watching:

We are moving most of the articles in this section to the FOA's Pinterest Page "Worth Reading" - Go there for the latest links

Sign up at the FOA  Pinterest board Pinterest

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  

Measuring Optical Power In Communications Systems 

Like Crossword Puzzles? Here's Some On Fiber Optics

EP crossword

Do you like crossword puzzles? How about one on fiber optics - or maybe a half-dozen of them? FOA Master Instructor Eric Pearson of Pearson Technologies has created a series of crossword puzzles on fiber optics that are keyed to the FOA CFOT reference materials and his book Professional Fiber Optic Installation, v.9. You can have fun and study fiber optics at the same time!

This months crossword puzzle is on "Optoelectronics and Splicing" - Download the crossword puzzle on 
"Optoelectronics and Splicing."

If you missed the earlier puzzles, here they are:
Download the PDF file of the crossword on "Light and Fiber".
Download the PDF file of the crossword puzzle on "Cables".
Download the crossword on "Connectors & Splices."

Older Fiber, Do You Know How Good It Is?

There's millions of miles of long distance fiber installed around the world and most of it likely to see an upgrade of the systems operating on it, probably in the near future. Twenty years ago, most of it was probably running at ~1Gb/s, ten years ago it was probably 2.5 Gb/s, recently it was likely to be 10Gb/s but now many are being considered for 100Gb/s or beyond. Can the fiber support such speeds? Can it be "repaired" or "modified" to make it possible to use it at higher speeds? If you own that fiber, can you say what it is worth without knowing its future upgrade capability.

In order to know the potential for upgrades on your cable plant, you need to test it. This process involves a number of tests and is called "fiber characterization." Greg Stearns of TTP-US, an FOA Corporate Member, performs these tests and has written a short article on why you need to characterize fiber and how its done. Read about fiber characterization from someone who does it often and can explain it well.

Download the paper here (PDF, 80kB).

Where In The US Do Contractors Need Licenses For Fiber Optics?

We often get asked where in the US do contractors doing fiber optic installations need licenses. We found a good website for that information, the NECA -NEIS website. You might remember NECA-EIS, as they are the partner with the FOA in the NECA/FOA 301 Fiber Optic Installation Standard. NECA is the National Electrical Contractors Association and NEIS stands for National Electrical Installation Standards. They have a very easy to use map and table that gives you data on every state in the US, so mark these pages for future reference.

NECA/NEIS (See “State Regulations”) (all electrical licensing)
Low Voltage:

Benchmarking Fusion Splicing And Selecting Singlemode Fiber
We've been asked many times "How long does it take to splice a cable?" It's not a simple answer as it varies with the number of fibers in the cable and the work setup, including whether one or two techs are working at a job site. FOA Master Instructor Joe Botha of Triple Play in South Africa did his own analysis based on decades of experience both splicing cables and teaching others how to do it properly. This is one of the best analyses we have seen because Joe includes prep times as well as splicing times and differentiates between one tech and two techs working together. He adds some other tips on fusion splicing too. This should be mandatory reading for every tech and given to every student! Here is Joe's splicing analysis. 

Joe also has an excellent writeup on how to choose singlemode fiber that helps understanding the different types of G.6xx fiber. Read it here.
And you will want to read Joe's report on splicing different types of SM fiber, including bend-insensitive (G.657) fiber. Read it here.

Free - Mike Holt's Explanation Of The US National Electrical Code (NEC) For Communications Cables
Mike Holt is the acknowledged expert of the US National Electrical Code (NEC). His books and seminars are highly praised for their ability to make a very complicated standard (that is in fact Code - law - in most areas of the US) easily understood. Part of the appeal is Mike's great drawings that make understanding so much easier. Mike makes Chapter 8 of his book available free. It covers communications cables, telephones, LANs, CATV and CCTV, for premises applications. Even if you live in a region or country where the NEC is not the law, you may find this interesting.
Download Mike's Chapter Here

Good Technical Website For Installers
American Polywater ( has one of the best technical website for cable installers. Check out their website, especially “Videos,” “Engineer’s Corner” and  “Calculators.”

Fiber Optic Safety Poster
We've had numerous requests to reprint our guidelines on safety when working with fiber optics, so we have created a "Safety Poster" for you to print and post in your classroom, worksite, etc. We suggest giving a copy to every student and installer.


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

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   

Electrical/Low Voltage Workers in Wisconsin
Casey Healey, Business Agent for IBEW Local 159 in McFarland,WI suggested a link to the Wisconsin Electrical Workers on the FOA jobs website. They have nine IBEW locals that cover the entire state of Wisconsin. All nine locals use this website in search of low voltage technicians that are certified in copper or fiber. After an individual fills out the employment opportunities form on the website a representative from that person's area would be in contact with them to discuss job opportunities within the IBEW as a low voltage apprentice, trainee or a technician. In Wisconsin they teach the 3 year NJATC Voice Data Video apprenticeship program. WI JATCs use the books that FOA has written for the NJATC in their curriculum

 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.


Remember To Renew Your Certification !

Remember to renew your FOA certification. All current CFOTs have a ID Card with their certification data and we keep a database of current CFOTs to answer inquiries regarding your qualifications if needed.  If you forgot to renew, use the online application form to renew NOW!

You can now renew your FOA certification online - and get an extra month free. Details here.



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Read the complete FOA Privacy Policy here.

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

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.
Contact Us
The Fiber Optic Association or email <>

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