The
Optical Fiber "Family Tree"
We recently tried to explain all the fibers available and
how they developed, so we created this diagram - the Optical
Fiber Family Tree. It may help you understand the varieties of
fiber and their designations.
OFC
Conference Coming To Los Angeles In March
OFC -
Optical Fiber Communications - probably the world's largest
fiber optic conference and exhibits - will run March 19-23, 2017
at the Los Angeles Convention Center. OFC is certainly the
oldest fiber optic conference - for over 40 years, OFC has drawn
attendees from all corners of the globe to meet and greet, teach
and learn, make connections and move business forward. OFC
attracts the biggest names in the field, offers key networking
and partnering opportunities, and provides insights and
inspiration on the major trends and technology advances
affecting the industry.
Interestingly, the list of "Who Should Attend" company
categories does not mention the very people who build fiber
optic networks! Certainly the technical presentations are not
aimed at the practical issues of fiber optic network design,
installation and operation, but contractors and installers will
find the exhibits interesting and fun to visit - a massive
display from almost 600 companies from 60+ countries of every
fiber optic component, subsystem, tool, test equipment and
gadget known to the industry!
Technical Conference:19 – 23 March 2017
Exhibition:21 – 23 March 2017
Los Angeles Convention Center, Los Angeles, California, USA
OFC
Conference Information Register
For Exhibits (Free)
OFC
One-Upmanship
Every year
the technical talks at OFC tout the latest achievements of
R&D. This year we got a press release from NTT in Japan that
they would talk about a new singlemode fiber with 12 individual
cores in a single 125 micron glass cladding. That beats Sumitomo
who discussed their 8-core fiber!
Sumitomo's 8-core fiber from OFC 2016
The
Continental Automated Buildings Association is holding its next
Intelligent Buildings & Digital Home Forum will be held
April 26-28, 2017 in Silicon Valley. This year's CABA Forum will
be co-located with Intel Corporation, a CABA Board Member, at
their campus in Santa Clara, CA.
Program information and registration for attendees is now
available online at: http://www.caba.org/forum
and highly discounted early bird pricing and hotel rates will be
in effect until March. The conference hotel will be the Biltmore
Hotel & Suites, where a number of event sessions will also
be held.
This year's CABA Intelligent Buildings & Digital Home Forum
will bring together leading organizations involved in the
integration of intelligent building systems and connected home
technologies. CABA estimates that over 250 industry stakeholders
will gather to discuss current trends in the intelligent and
integrated buildings and connected home sectors.
CABA's Forum will be an opportunity to attend the organization's
Council meetings and network with the majority of the CABA Board
of Directors during the entire event. The Forum will also
feature keynote speeches by Neil R. Tunmore, Corporate Vice
President and Director of Corporate Services at Intel
Corporation; and Aglaia Kong, CTO of Corporate Networking at
Google.
There is a
conference for the "Call Before You Dig" business. The CGA 811
Excavation Safety Conference & Expo is committed to
providing education and training for all professionals active in
the damage prevention community. Educational tracks are also
offered for the following industries: Electric, Engineering,
Excavator, GIS, Government / Regulatory, One Call Board, One
Call Centers, Public Works and Trenchless.
They have a special symposium for fiber protection that should
interest contractors and fiber cable plant owners.
The conference is March 14-16, 2017 at the Shingle Creek in
Orlando, FL.
Go
here for more information.
New
Website Keeps You Up To Date On Structured Cabling
Liz
Goldsmith, manager of the TIA Fiber Optic Technology Consortium
(FOTC) has started a new website that aims to keep readers up to
data on the news and products in the structured cabling
(premises cabling) space. Called Structured
Cabling News, it offers news about the industry in more
than a dozen categories so you can browse the news by categories
(like fiber) that interest you most. Liz sums up the aim of SCN
as "SCN brings you current Structured Cabling News curated by
category and topic. We search the 'Net so you don't have to -
updated daily with industry trends, new products and best
practice from industry leaders."
And you can subscribe to daily or weekly digests to keep
yourself informed.
Structured
Cabling News
Training
Done Right - BDI Datalynk's Hands-On Labs
Most photos
you see of hands-on labs involve students sitting at tables
terminating or splicing fiber, maybe testing fiber on spools. BDI
Datalynk's Bob Ballard (remember Bob, the treasure hunter,
diver and model/real airplane builder) designed his lab with the
same enthusiasm he has for his hobbies. He and his instructors
set up a lab for their courses where students build, test,
troubleshoot and operate networks. Each instructor has a SUV
filled with gear that allows them to create a realistic
operating environment for their students, ensuring they learn
the installation processes they will see used in the field.
Building the network in a lab exercise
Using a VFL to trace fibers
Testing the fiber links for loss
More on BDI
Datalynk and their class offerings.
Meet
Another FOA Instructor
Milt Murry
has been an FOA CFOS/I instructor for more than 15 years. He
holds CFOT #545 and has been recognized as a FOA "Master
Instructor." Milt sent in this photo from a recent training
session in St. Louis where he lives.
Milt is representative of FOA's Master Instructors -
decades of experience in the field (he's still doing
installations) and in teaching - imparting his wisdom to his
students.
Who
Knows Tools Better Than A Instructor?
Several FOA
schools also distribute tools and test equipment based on what
they know works best from their field experience and how they
see their students adapting to using these tools. We'll do a
future article about all of them, but we want to bring to your
attention a new one started by Bob Ballard of BDI Datalynk that
has a unique focus - OSP construction tools and equipment.
Bob has been running the "Fiber
Optics Tools" website for years now, providing proven
tools to his BDI
Datalynk fiber optic training students and many
others in the fiber optic market. Now Bob has launched a new
site selling OSP construction tools - "Linesman
Tool Supply"" that offers a complete line of aerial,
underground, and cable placing tools for the outdoor telephone,
data, power, and CATV cable placing trades. The site has a lot
of really useful tools and safety supplies for OSP construction
that are sometimes hard to find from bigger distributors.
Update
On How OTDRs Measure Reflectance
In
the September 2016 FOA Newsletter, we printed an article on how
OTDRs measure reflectance and how it had considerable
measurement uncertainty. We're reprinting it here with some new
information we encountered recently. The actual method used by
OTDR manufacturers is even more prone to uncertainty than we
thought! So we though we'd reprint it in its entirety with a
update.
The
Real World - Reflectance and OTDR Measurements
FOA
often gets questions from the field that are complicated
technical issues compounded by misunderstandings of product
performance and testing limitations. Here is an example from
recent conversations about a real world problem.
Here's
The Question:
In a project, the customer is requiring a contractor to test
connector reflectance and requiring -55dB for each
connection. They are using fusion spliced pigtails with
UPC factory connectors. They are measuring with an OTDR,
but they can’t seem to meet the -55dB reflectance requirement on
the connectors. They are getting (-51dB – (-54dB) on a
consistent bases and continually cleaning and inspecting.
I told them going into this that on the lengths of fiber they
are measuring they will have a hard time getting individual
reflectance measurements to meet the -55dB value unless they use
angled polished connectors. The lengths are 2,000’ –
9,000’+ and the way OTDRs measure reflectance will make it hard
to get that precise.
I am having them take the OTDR out of “auto” mode and shorten
the pulse width and increase the averaging time to try and get a
little more accurate measurement, but still not sure that is
going to fix the problem.
Any suggestions?
Background:
How an OTDR Measures Reflectance
This is the drawing we showed in the original article. This
is not quite the whole story - it's too simplified.
Update: The drawing below is how the OTDR actually has
to calculate the reflectance. Reflectance is measured as the
ratio of the reflected signal to the incident test signal.
In order to
measure reflectance, you need to measure the value of the test
signal and the value of the reflectance. Measuring the value of
the reflectance is straightforward, just measure the power level
at the peak of the reflectance pulse. Measuring the test signal
at that point is more difficult. You can't exactly put a power
meter there, so you use an indirect method. You can measure the
backscatter level of the fiber and you know the typical
backscatter coefficient of the fiber so you add in the
backscatter coefficient to get the signal level.
However, the backscatter level is not a nice precise number.
Here is a table from a fiber manufacturer:
|
Wavelength
(nm)
|
Fiber
Backscatter
(1
ns test pulse)
|
|
850
(MM)
|
-67
to -70 dB
|
|
1300
(MM)
|
-74
to -76 dB
|
|
1310
(SM)
|
-77
to -80 dB
|
|
1550
(SM)
|
-81
to -82 dB
|
|
1625
|
-82
to -3 dB
|
So
to determine the signal level, you have to determine the
backscatter level from the trace, add in the fiber
backscatter coefficient with its 2-3 dB uncertainty, then
calculate the reflectance from the test pulse, correcting
all along for the pulse width and shape. And then, you also
have the issue on noise on the backscatter level.
Now
do you see why we say that reflectance has an uncertainty of
+/-2-3 dB?
Answer:
In this case, we’re looking at UPC connectors. They are
generally specified as ~ -45 to -50dB reflectance, and that can
be +/-5dB because the reflectance can’t be measured that
accurately, especially at that level.
A reflectance of -55dB means that a few parts per million of the
incident light is being reflected. To make the measurement, you
have to measure that reflected light against the backscatter
level. Both are low level, in this case -55dB reflectance level
and ~ -75 to -77dB backscatter level. The OTDR is basically
trying to measure a few PPM compared to a signal 100 times
smaller!
If you reduce the pulse width the amount of power in both
decreases significantly making the signal/noise ration worse.
With signals this small, you are working near the noise level of
the instrument and no amount of averaging can improve the
signal/noise ratio enough to get an accurate measurement. I’ve
never done actual tests with an OTDR myself to get statistics,
but I’d bet the measurement has an uncertainty of much more than
+/-5dB.
Furthermore, you must be cautious with selection of pulse width.
In a Corning
document on reflectance, they say the amplitude of a
reflective feature on an OTDR trace appears larger when measured
by shorter pulse widths and therefore are often misinterpreted
as a cause for concern during cabling or installation
measurements.
Update
: OTDR traces
Just look at the difference in the reflectance pulse with
different test pulse widths
If the customer really wants or needs -55dB, they really
need to use APC connectors where the angle polish all but
eliminates reflectance. That’s what we’re seeing in most short
SM applications today (FTTH, passive OLANs, data centers, etc.).
And good luck testing them!
Size
Matters
Small
Connectors
With a
movement to smaller fibers to allow making higher fiber count
cables, it's understandable that higher density in patch panels
would lead engineers to think about smaller connectors. So SENKO
has announced the "Micro LC," an even smaller version of what
was called a "small form factor" connector when it debuted
almost 20 years ago.
The big advantage is its short - 30mm (0ver 1") shorter than a
regular LC with it's strain relief boot and does not need lots
of room to insert. We didn't see it on the datasheet, but we
wonder if there is a tool that makes it easier to insert/remove.
More
info form SENKO.
Small
Cable
TiniFiber
has introduced TiniFiber® Single Jacket Power Cable, a TiniFiber
fiber + power cable allows the installer to run TiniFiber®
Micro Armored Fiber™ Optic cable and a power cable in a
single jacket! This cable is a quick fix for space, cost &
saving time for the end user in the installation of CCTV cameras
or other fiber-connected devices that require power. TiniFiber®
Micro Armor Fiber Cable adds armored protection and
ease for indoor/outdoor premises installation. Power cables can
be 2, 3 or 4 conductor with 12 to 22 AWG options and the fibers
are available in a variety of glass types and strand counts.
Confusion exists over the name
for a cable of this type. Traditionally it has been called a
"composite" cable, but some people call it a "hybrid" cable.
Others say a hybrid cable is one that has both singlemode and
multimode fiber in the cable.
TiniFiber®
Single
Jacket Power Cable
Interested
In A Career 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 www.foa.org/careers/.
New
Edition Of Eric Pearson's Fiber Optic "Cookbook"
Eric
Pearson of Pearson Technologies Inc. announced the availability
of Professional Fiber Optic Installation, v.10. This
recently updated training, field, and reference text is a
comprehensive presentation of the information essential to
successful fiber optic installation.
This text assists the installer in achieving the three
elements of success: low power loss, high reliability, and low
installation cost. This text is the ideal tool for three types:
those who wish to become professional fiber optic installers;
for instructors who want to use the most comprehensive training
manual available; and for those who want to pass the Fiber Optic
Association CFOT and CFOS/C/S/T certification examinations.
Continuously developed and tested over the last 24 years during
both fieldwork and training presentations, this text includes
both the information essential to understand the reasons for the
installation rules and detailed procedures for installation,
inspection, certification, and testing of cables, connectors,
and splices.
For additional information, contact: Pearson Technologies Inc.,
fiberguru@ptnowire.com,
www.ptnowire.com,
and 770-490-9991.
A New
Way To View Fiber Optic Connectors
Microscopes
are used for inspecting connectors for two primary purposes,
checking polished ferrules during termination to ensure proper
end finish and checking connectors in the field to determine if
they are clean. To date, one type of microscope has been used
for both operations, but a new tool from a long time industry
expert may change some minds. To inspect polish quality, you
need high magnification, typically 100 to 400X, with most users
preferring the higher magnification. But if you inspect for dirt
at that magnification, you can only see the ferrule end,
ignoring the rest of the connector which can be filthy and you
will never see it.
Ed Forrest, the "guru of cleaning" has come up with a very
useful tool. Ed is well known for his website on cleaning and
his books (go to http://fiberopticprecisioncleaning.com/)
and has now added a product for inspecting connectors for
cleanliness. Instead of a standard microscope, the RMS-1
Fiber Optic Inspector uses a zoom microscope attached to a
PC with unique 3D-printed adapters to hold connectors. You get a
wide angle view that can show you how clean the connector is
really. The biggest advantage is its ability to see the whole
MPO connector or into the shell of large multi-fiber connectors
like the MIL-38999.
Looking inside a SC connector with the RMS-1
You have probably never seen a MPO connector in this way before
More views of SC, LC and MPO connectors
Here is the datasheet
on the RMS-1 Fiber Optic Video Scope
This product is different than other microscopes in many ways.
It attaches to a PC or Netbook. The 3D printed adapters take
some getting used to, but the results are reallu useful. Ed is
still in the development phase, so there is no website yet. Here
is his email if you want more information: edwforrest@gmail.com
Locating
Underground Utilities - An Overview of Methods
In searching for articles on underground utility location
regarding the problems caused by contractors digging up
cables and breaking water pipes, we found this
interesting summary of methods of location. It
includes electromagnetic, acoustic and radar methods, plus
one we did not expect - dowsing. Dowsing is a technique for
searching for underground water, minerals, or anything
invisible, by a person carrying an indicator, traditionally
a forked stick, now often paired bent wires, pointing
downward toward whatever they are searching for supposedly
in response to unseen influences.
We suggest more modern technical methods of searching for
buried utilities, but whatever you do, use the resources
available before you start digging! Read
the FOA Tech Topic. There is a toll-free "call before you
dig" number in the USA: 811. See www.call811.com
for more information or go to National
Fiber Optic 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
- But
if anyone really has experience with dowsing, tell us about
it!
New
Viavi Database Illustrates More Than 500 Operational or
Planned Deployments Of Gigabit Broadband Globally
Communications service providers worldwide are accelerating
efforts to deliver gigabit internet -- network speed that is 159
times faster than the global average of 6.3 Mbps. The Gigabit
Monitor, a visual database referencing current and planned
gigabit deployments around the world, from Viavi Solutions (the
test equipement company formerly known as JDSU). The Gigabit
Monitor paints a picture of mobile, cable and telecom service
providers all racing to deliver lightning-fast internet
connectivity to meet end users' demands. The database, developed
completely from public information, is available at: http://www.gigabitmonitor.com.
Below are some of the key insights from the Gigabit Monitor:
- State
of gigabit: There are now at least 350 live gigabit
deployments globally, with a further 164 announced or under
construction, across wireline and wireless technologies
including GPON, DOCSIS 3.1, G.fast, LTE-A, 5G and 802.11ac.
- Contrasts
by region: North America has the largest share of announced
gigabit deployments, with 61 percent. Europe is second with
24 percent. Asia, Australasia, Middle East, Africa and South
America share the remaining 15 percent of deployments.
- Deployments
accelerate: The pace of gigabit deployments has accelerated
sharply. Over 70 percent of the live gigabit deployments
tracked have been launched since the start of 2015.
- Fiber
dominates: 85 percent of currently known gigabit deployments
are based on optical fiber connectivity. 11 percent are
based on Hybrid-fiber coax (HFC), a broadband technology
that combines optical fiber and coaxial cable, commonly
employed by cable providers.
- Wireless
gigabit is already here: Nearly 3 percent of known gigabit
deployments are based on LTE-A, a modified version of LTE
which is gigabit-capable.
- 5G is
coming fast: 37 wireless carriers have announced plans for
5G networks. Five of them plan to have 5G networks built as
early as 2017.
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: http://www.fhwa.dot.gov/policy/otps/exeorder.cfm
From the Council of State governments: http://www.csg.org/pubs/capitolideas/enews/cs41_1.aspx
From the city of San Francisco: http://sfgov.org/dt/dig-once
An article about Dakota County, MN: https://muninetworks.org/tags/tags/dig-once
And
the one to download and hand out:
A “How To” Guide from The Global Connect Initiative: https://share.america.gov/wp-content/uploads/2016/04/6.-GCI-Dig-Once.pdf
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:
Want To
Learn More About DIY FTTH?
Southern
Fiberworx is a DIY FTTH Project in Georgia
It seems
like every week FOA gets another call from a town, real estate
developer or utility wanting to start a FTTH project for their
area. FOA has created several videos and a a web page on this
topic to help anyone get started.
FTTH
Case Studies: Do-It-Yourself FTTH
FOA has a
series of videos on do it yourself (DIY) FTTH. The first three
videos are online now:
FOA
Lecture 45 Do It Yourself FTTH (Fiber to the Home) What's
involved in building a FTTH network of your own.
FOA
Lecture 46 Do It Yourself FTTH (Southern Fiberworx)
(FOA Newsletter
November 2015) How one company, Southern Fiberworx in
Cordele, GA did it themselves.
FOA
Lecture 46 Do It Yourself FTTH (Southern Fiberworx)
(FOA Newsletter
November 2015)
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 http://www.ecmag.com/contributing-authors/jim-hayes
and you can see all of them.
Keep Up
With Google Fiber News
Google is
moving ahead in Austin and starting in the SE building Google
Fiber networks. They just announced projects in San Diego and
Irvine, CA and Louisville, KY. Here is where to keep track
of what is happening with Google Fiber - the
Google Fiber Facebook page!
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 www.foa.org/careers/.
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.
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 Fiber, Fiber
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.
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 membership fee. 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.
Safety
On The Job
Safety is
the most important part of any job. Installers need to
understand the safety issues to be safe. An excellent guide to
analyzing job hazards is from OSHA, the US Occupational Safety
and Health Administration. Here
is a link to their guide for job hazard analysis.
FOA also has lots of information on safety: FOA
Guide, YouTube
video and a Safety
Poster
"Worth
Reading" Is Now On
Join
FOA on Pinterest.
We have been posting links to pages "Worth
Reading" on a special FOA Pinterest page. You can join and
keep up to date with the news on our industry which we put
there.
Recent
posts cover utilities using new generation telecom, India's
plan for 100 smart cities, Cincinnati Bell bets on fiber,
various opinions on the US battle over net neutrality, etc.
Good
Practice Tools For OTDRs, All Free
FOA
OTDR Simulator
You
may already know that the FOA has a free OTDR Simulator you can
download from our website (go
here for directions) that allows you to practice using an
OTDR on your PC (Win XP or 7), seeing the effects of changing
setup parameters and analyzing dozens of real world traces. But
here are two more tools that can be good for practice.
OTDR
FAQs
Including
more hints from FOA Master Instructor Terry O'Malley like tests
on what the end of a fiber trace looks like with broken and
cleaved fibers.
Frequently
Asked Questions On OTDRS And Hints On Their Use
"Fiberizer"
APP Reads, Analyzes OTDR Traces
Fiberizer
is a iPhone/iPad APP that reads industry-standard ".sor" format
files and allows trace analysis on your iPhone or iPad. An
android version is in the works too. Read
more about Fiberizer. And
here are more directions on its use.
Events of
Interest
FOA
posts these events not on our LinkedIn groups
FOA
has three LinkedIn Groups
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)
RETURN
TO INDEX
 What's
Happening @ FOA
FOA
Standards:
FOA now 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.
NECA/FOA
301 Fiber Optic Installation Standard
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.
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TO INDEX
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.
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.
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 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
FOA
Basic Fiber Optic Textbook Now Available in French and
Spanish
FOA
Reference Guide To Fiber Optic Network Design And FOA's
Outside Plant Fiber Optic Construction Guide
Read
More about the FOA
Reference Guide To Fiber Optic Network Design
and
More
information on the FOA
Outside Plant Fiber Optics Construction Guide
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TO INDEX
FOA
iPad Apps
FOA
LossCalc
 FOA
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. http://itunes.apple.com/us/app/foa-losscalc/id476262894?mt=8&ls=1
Self -Study in Fiber Optics
 Our
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.
http://itunes.apple.com/us/app/foa-guide/id434354283?mt=8&ign-mpt=uo%3D4
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TO INDEX
The
FOA has many videos on ,
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.
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 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.
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TO INDEX
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  .
Find
What You Want Using "Google Custom Search
 There's
so much information on the FOA Tech Topics and Online Fiber
Optic Reference Guide that even a well-organized Table of
Contents isn't enough and when the material is always changing,
an index is impossible to maintain. So the FOA is using the
latest technology in search, Google Custom Search, which will
allow you to search just the FOA Tech Topics and
Online Fiber Optic Reference Guide for any topic you want to
find more about. Try
it!
Go
to The
FOA Online Fiber Optic Reference Guide.
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TO INDEX
New
Schools
The FOA welcomes the newest additions to our listing of FOA-Approved
Training Organizations:
Owensboro
Community and Technical College, Owensboro, KY, USA. School
# 358
Ashalnd Community & Technical College, Ashland, KY, School
# 359
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
Feedback
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.
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.
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TO INDEX
Good
Question! Tech Questions/Comments Worth Repeating
Real
Questions From FOA Newsletter Readers
Polishing
Films
Q: Are there different grades (micron) polishing
films/papers for multimode and single mode fiber cables in ODF
termination ? If yes, What are the grades polishing papers for
multimode 50/125 um and 62.5/125 um fibers.
A: The polishing of MM
and SM fiber is indeed different. Both start with an “air
polish” with 12micron alumina polishing film to remove the
protruding fiber. Then the polishing continues on a soft
polishing pad (3mm 80 durometer rubber).
MM uses a 3micron alumina polishing film polished dry then a
final 0.3micron alumina film polish. See
http://www.thefoa.org/tech/ref/termination/ConnHints.html
SM is usually done with a wet polish using as special polishing
slurry and diamond polishing film. The diamond film will polish
both the ferrule and the fiber to get the best end finish. See http://www.thefoa.org/tech/ref/termination/sm.html
There are even more pages of information on the FOA Guide at http://www.thefoa.org/tech/ref/contents.html#Components
Armored
Indoor Cable?
Q: Can I get an indoor armored 8 core fiber optic
cable?
A: Most cable
manufacturers make indoor armored cable using corrugated wrap
armor to protect cables from crushing loads from other cables
especially in under floor installations.
MPO
Connector Loss
Q: Is there a current standard, for maximum allowable
loss, for MPO fiber connectors? If so… what is the standard #
from EIA/TIA? (Was it amended in 568B, since they were
introduced?) Would it be similar to standard connectors @ 0.75dB
Max allowable loss?
A: The MPO is covered
under the TIA 568 standard. All fiber optic connectors are the
same - 0.75dB.
There are discussions being held at TIA and ISO/IEC on using a
different method of specification, statistical in nature, that
says X% would be less than YdB in several stages from 0.1-0.2 to
over 1dB, but it’s led to some headed discussions.
MPOs for MM are probably no less than 0.5dB and SM are near the
0.75dB mark. At least the SM ones are APC (usual 8 degrees, but
still a flat polish).
I’ve recently learned that MPOs are polished for fiber
protrusion to try to get fiber contact, but the evenness along
the line of fibers is harder to control.
image from SUMIX
showing protruding fibers in MPO connector
More Than “Single” Mode?
Q: We're now using SM fibre so it looks like we don't
need mandrels in the Ref Lead at the Light Source. The
info I have is that we need to make a couple of air coils 35mm
to 50mm in diameter. Why?
A: When you launch from
a pigtial laser source through a connector into a reference
cable, you do have several modes being propogated. It usually
takes 100m or so for the second or third order modes to
attenuate. So the coil causes them to be attenuated by the
stress enough to no longer be significant - it’s a mode filter
just like MM. If you do not do this, you will measure higher
loss in the fiber and at connections near the source. Since most
SM has traditionally been long distance, the effect was small or
ignorable, but with short links, it can be significant.
Followup Q: But how do we explain multiple modes in Single Mode
fibre?
A: When you get the core of the fiber down to ~5-6 times the
wavelength of the light, it no longer acts like geometric optics
(like MM fiber). Some of the light can travel outside the core
(see the note on “waveguide
dispersion”here http://www.thefoa.org/tech/ref/testing/test/CD_PMD.html).
At launch, significant amounts of power are at higher angles
creating short lived modes that are highly attenuated.
Replacing OM1 MM Fiber
Q: We are an automation system integrator in South
Africa. We have a client that has multimode 62.5/125 fibre optic
plant wide. None of the runs between components are longer than
2km. We intend to upgrade the technology from a proprietary
communication protocol to a standard ethernet protocol at 100
MHZ. The fibre to copper convertors we will be using are using
1300nm light source and have a Fibre Optic Link Budget of 12.8dB
for 62.5/125 um and 9.8dB for 50/125 um. The
client has been advised to replace the multimode 62.5/125 with
multimode 50/125 cabling and we need to know if this is really a
requirement.
A: Do you know how old
the fiber is? It should be what we called FDDI grade 62.5/125
fiber with a loss of ~1dB/km and a bandwidth of 500MHz-km
at 1300nm. A 2km link should have a loss of 2dB for the fiber
and ~0.5dB/connection - well under the power budget of the link.
100Mb/s Ethernet variants were designed for 2km or more on this
fiber. There is no reason to upgrade at this time, 50/125 fiber
would not be needed until Gigabit Ethernet was desired.
Bi-Directional OTDR Testing
Q: Should the testing be done with the same piece
of equipment from both ends then merge the results or does that
not matter - can you use traces from two OTDRs as long as the
test equipment is compatible and settings are adjusted properly.
A: Yes, you should use
the same test set from each end but this way - take a trace,
disconnect the OTDR from the launch cable and go to the far end
of the receive cable and connect it there to take the second
trace. The usual way people do bi-directional tests is to
disconnect the launch cable and take it to the far end and shoot
back up, often not using a receive cable at all, figuring they
get the far end connector on the second test. But when you
disconnect the launch cable (and/or the receive cable) you lose
the connection you want to test in the other direction! As for
using the same OTDR, every OTDR is different and the results you
get may be significantly different, esp. if they are not
calibrated recently - and few OTDRs are ever calibrated.
Passive
OLANs in Hotels And Resorts
Q: Are passive OLANs a good choice for hotels or
resorts?
A: Passive Optical LANs
are enterprise networks based on fiber to the home (FTTH)
technology not Ethernet over structured cabling. The FTTH
network is usually using GPON standard equipment over one
singlemode fiber with passive optical splitters that provides
basic Level 1 and 2 network functionality. This is not Ethernet
but carries Ethernet over the GPON protocols at 2.5G downstream
and 1.25G upstream.
Passive OLANs offer several advantages over conventional
Ethernet switches and structured cabling, including much less
cost (~50% capital expense and ~20% operating expense),
much lower space requirements (see the link to the library
photos below and note the two racks of equipment that support
4000 drops), longer distance requirements (to 20km), easy
expansion (these are systems designed for hundreds of thousands
of users) and easy management (when you have hundreds of
thousands of users, that’s important.)
For hotels, convention centers and similar facilities, the ease
of upgrading to a passive OLAN is a big advantage - one fiber
goes from the computer room to a splitter where it can serve 32
switches of 4 ports each. That’s right, one fiber can support
128 users! It can support anything that a network can - wireless
access points, security cameras, secure entry systems, VoIP
phones or POTS phones - anything that will run over a
conventional network.
Calibrating
An OLTS
Q: I have a question about the OLTS - do you have to
recalibrate it every day ?
A: Any optical loss
test set needs to be calibrated for “0dB” whenever anything
changes - the launch cable - source output - or even every few
tests to ensure the connector is clean and undamaged - plus they
wear out. See 5
different Ways To Test Fiber Optic Cables.
Insertion
Loss
Q: I have not been able to find a good definition of
“optical insertion loss” or “insertion loss” or “optical loss.”
A: Insertion loss was
the term originally used for the loss of a connector tested by a
manufacturer. They would set up a source and length of fiber
connected to a meter, measure power, insert a pair of connectors
and measure the loss. Since it was an inserted connection, it
became known as insertion loss.
Over time, the term insertion loss became more widely used to
contrast with the loss measured by the OTDR, an indirect
measurement using backscatter that may not agree with the loss
with a light source and power meter.
Insertion loss, therefore migrated to meaning a loss measured of
a cable or cable plant inserted between the launch and receive
cables attached to a light source and power meter for double
ended testing used with installed cable plants. For patch cord
testing, you do not use a receive cable attached to the power
meter but connect it directly to the cable under test, making
the test just include the one connection to the launch cable.
Two other terms often mixed up are attenuation and loss, which
are essentially the same, except when discussing a fiber. In
fibers, attenuation is often used instead of attenuation
coefficient. Attenuation is the absolute loss i dB while
attenuation coefficient is the characteristic attenuation of a
fiber expressed in dB/km.
Here is probably the best explanations: http://www.thefoa.org/tech/ref/basic/test.html
Old
Fiber
Q: We are looking at a company’s fiber network which
has been laid at various points in time over numerous
years. In this process, we are trying to identify the
changes that were made to either/both the glass fiber and the
cladding. Are there different generations of what was
industry standard in creating the fiber? For example, are
you able to identify the difference in a fiber that was laid in
1980 versus one laid today? Was the cladding the same
size/thickness etc. in 1980 as it is today or has this been
modified/improved upon over the years? In all, we are
trying to find what modifications have been over the years and
how this may improve the life of the network and its
capabilities.
A: This is a common
problem today. Many network operators are evaluating their fiber
networks for upgrades, hampered by the fact that few are
properly documented. Below is a timeline that should answer your
questions. What many network owners are doing now is testing
their cable plants - a process called Fiber
Characterization. There are contractors who do this
service.
Fiber
Tech Timeline
1976 -
First field trials, US and UK, using multimode fiber at 850nm
1980 -
First long distance networks still using multimode fiber at
850nm, planning to upgrade with wavelength-division
multiplexing at 1310nm
1984 -
singlemode fiber becomes feasible, telecom drops multimode
fiber, all future installations are singlemode - this first SM
fiber with a 9 micron core and 125 micron cladding is still
available today but with better specifications. Really early
fiber may not have good environmental protection and degrades
over time. Early speeds were 145-405Mb/s, up to 810Mb/s by the
end of the decade.
1990 -
around this time, modern fiber begins - better performance and
environmental protection. Fibers for wavelength-division
multiplexing in the 1500nm range appear allowing multiple
signals on a single fiber and fiber amplifiers allow long
spans.
1995-2000
- massive build-out of fiber backbone leads to glut of fiber -
WSJ ~2001 says 93% of all fiber is dark. Speeds grew from
1.2-10Gb/s over the 90s decade
2000-date
- massive Internet growth and mobile device growth eats up
glut of fiber and demands many times more. Dense
wavelength-division multiplexing becomes the norm. Speeds
began at 1.2/2.5Gb/s, upped to 10, 40 and are now at 100Gb/s.
So most fiber installed after 1990 has the possibility of being
used at 10Gb/s, after 2000, it’s probably OK for 40Gb, and since
2010, you are probably OK for 100G and maybe more. To
verify performance, you test each fiber for connector condition,
loss, spectral attenuation, chromatic dispersion and
polarization mode dispersion. There are test sets that will do Fiber
Characterization in basically one step.
Fusion Splicing Live Fibers
Q: Is it safe to fusion splice a live fiber, or is
there a chance that
the light from the arc will damage the detectors in the modules
at the end (20km-rated SM for us).
A: I have never heard of
this being a problem. The amount of light coupled into the fiber
from the splicing would be very small compared to a properly
coupled laser. When a cable is broken you might be splicing the
fibers that are live without knowing which are live and not
caring. On your newer splicers this is not a problem. On the
older splicers with the LID system you would have to reduce the
power to get a good splice which they would do by putting a bend
in the Fiber.
Duplex
Communications Over One Fiber
Q: Is true duplex over a single fiber possible, or is
more like a shared time-domain technique in a quasi-duplex mode?
I would guess that true duplex would lead to interference
problems.
A. Bidirectional links
are widely used - that’s how FTTH PONs work. They use splitters
to combine/split the signals and one wavelength downstream and
another upstream. See Fiber
Optic Datalinks and for FTTH FTTH
Architectures.
Using
Hybrid 2.5-1.25mm Connector Mating Adapters
Q. Can I use the hybrid 2.5-1.25mm adapters for
connecting SC connectors to LCs or MU connectors. It would make
testing much more convenient.
A: We do not recommend
them for most uses, especially testing, as they can be highly
unreliable. Reserve them for emergencies and use hybrid patch
cords instead.
Test MM Fiber @ 1300nm?
Q:
What is your opinion about the need for testing at 1300
nm on OM3 and OM4 fiber especially now that bend insensitive
multimode fiber is taking over?
A: It’s
unnecessary and costly. It’s rooted in the FDDI/100M days 25
years ago when 1300 LEDs were used and is now obsolete. The
only actual uses at 1300nm I know are the extremely rare
systems using 1310 lasers which may be standards but simply
don’t seem to ever be used. As you say, BI fiber makes the
issue of finding stresses moot.
Fiber In Service Loops
Q: We designing a rural utility system that will be
expanded to FTTH (or FTTR - fiber to the ranch in this case).
We're wondering how much excess fiber in service loops to add.
One software package is asking for 12% but that seems excess.
A: I
have typically seen 100 feet on straight through boxes
(reserves), 35-50 feet on cut ends for splicing and anywhere
from 15-25 feet at the premise depending on how much is
required for the termination device, positioning, etc. When
rough estimating we have typically used 10% over linear
distance.
Maintenance of Fiber Networks
Q: Can you guide me how to prepare Optical Fiber
Cable Annual Maintenance Proposal?
A: Basically, the
network needs to be installed properly, fully tested and
everything carefully documented. Then no routine maintenance
is required. Most problems with fiber optic networks occurs
when techs are working with it, e.g. damaging cables or
getting connectors dirty when testing, so leaving it alone is
the best plan.
Electronic transmission equipment can be tested anytime to
ensure proper data transmission, but that does not involve
accessing the fiber.
We have several things which may be of help:
You Tube Video: FOA
Lecture 39 Maintaining Fiber Optic Networks
Web page: Maintenance
I have 4 questions about OTDRs:
Q: What is dynamic range I read many time but
can’t understand yet, whether it is a range of losses can be
measured by OTDR for example if an OTDR has 45 dB dynamic range,
it can read the losses of point up to 45 dB or what it means.
A: I do not believe there is a standard definition of
dynamic range, but it is generally accepted to be the highest
loss of the longest cable where you can see the end of the
cable. That usually means using the longest test pulse and most
averaging and assuming the end of the cable has a
significant reflection.
Q: What is dead zone is it fixed in meters mean an
OTDR cannot measure up to initial 5, 10 or 20 meter
A: The dead zone is a function of the pulse width and
speed of the OTDR amplifier. For most OTDRs it’s about 2-3 times
the test pulse width.
Q: What Type of settings needed before launching a
test
A: See FOA
Lecture 18: OTDR Setup or the section "Modifying OTDR
Setup Parameters For Best Test Results” in
OTDR
testing. A: Basically you set up wavelength(s), test pulse
width (long enough to reach end of cable but short enough for
best resolution), index of refraction or group velocity (a
function of the fiber type and wavelength) and the number of
averages (enough to mitigate noise but not take too long)
Q: Reading a test with 1310nm and 1550nm - why values
different for a same length of fiber.
A: The attenuation of the fiber will be different at
each wavelength and the index of refraction which is different
at each wavelength causes a difference in length. The OTDR
measures length by measuring time and then multiplying that by
the speed of light in the fiber (which is the inverse of the
index of refraction.)
The FOA page "Frequently
Asked Questions About OTDRs" answers these
questions and more.
Getting
Old Cables Out Of Conduit
Q: How do you get old cables out of a conduit when
they are stuck?
A: Usually we are concerned about reducing friction
when pulling cables through conduit, but sometimes you need to
get them out. Here
is a page from American Polywater the leading lubricant
company with advice on the subject.
Manufacturing
Guide?
Q: Is there a guide published by FOA that provides
insight as to the process of fiber optic manufacturing? It's my
understanding that the guide stresses quality and controls to
ensure performance and reduce product loss?
A: We do have a guide
for manufacturers. It is mostly aimed at communications systems
and components manufacture. Here
is a link to download it.
How
Long Does Termination Take?
FOA received a request from a consultant recently wondering if
we had information on the termination times for fiber optic
cables. After some looking in our archives, we realized we had a
document online that compared times for various fiber optic
termination processes. The paper was written after several FOA
instructors did a comprehensive time and motion study on
termination processes. The document is about 15 years old but
still relevant.
You
can read it here in the FOA Online Guide.
Testing
Connectors (From A Patchcord Maker)
Q: What are the chief defining standard(s) that
specifies connector and assembly IL (insertion loss) and RL
(return loss or reflectance) for both SM and MM fiber?
A: The description on
our Guide is here: http://www.thefoa.org/tech/ref/testing/test/conntest.html
FOTP-34 covers connector testing as a qualification test
for the type of connector - basically a "destructive" test for
connector manufacturers.
Reflectance is described on that page and here also: http://www.thefoa.org/tech/ref/testing/test/reflectance.html
Testing an assembly like a patchcord is covered under
FOTP-107 http://www.thefoa.org/tech/ref/testing/test/FOTP-171.html
Basic
Tests For Fiber Optic Cable Plants
Q: I did some research and I noticed that there is a
bunch of tests that can be done to fiber optics and I was
wondering if there is a list of primary tests that can be done
as a basic test.
A: Fiber optic testing
does have a hierarchy of tests.
- At
the top of the list is "insertion loss" testing which uses a
light source and power meter to test the fibers in the
same way that a communications system transmits over the
fiber. It is a simple test and the equipment needed is
inexpensive.
- Techs
will also use a microscope to inspect the fiber optic
connectors for dirt and damage, a big issue for fiber.
- The
instrument called an "OTDR" takes a snapshot of the fiber
using a technique like radar. Most outside plant cables are
tested with an OTDR and the data ( the snapshots are called
"traces") stored for future reference. OTDRs are more
expensive and require more training to use properly.
Here is a
link to a page on the FOA Guide site that explains the
technical,details: http://thefoa.org/tech/ref/testing/test/OFSTP-14.html
FOA also has information just for users of fiber optic networks,
see http://thefoa.org/tech/guides/UG3.pdf
How
to Clean POF (plastic optical fiber)
Q: I
heard that plastic fibres such as PMMA can suffer damage from
cleaning from an alcohol solution. Are there alternate cleaning
solutions available for these types of fibres."
A: You can use a 10/90
mix of isopropyl alcohol/water. Typically use with a lint
free swab. (from out POF consultants)
Testing
Bare Fibers With OTDR
Q: We are starting to test some OPGW cables. We have an
OTDR but we don’t find some reusable connectors. If we have to
test an OPGW with 48 fibres, we can’t set up 48 SC connectors!
Are there some reusable connectors in the commerce?
A: I assume you mean you
need to test with a bare fiber on the OPGW. For testing bare
fiber, use a splice, not a connector. Have a long pigtail on the
OTDR as a launch cable, long enough for the test pulse to
settle, say 100-500m, then use a splice for a temporary
connection. You can fusion splice the fibers then cut the splice
out or use a removable splice like the Corning Camsplice
(http://catalog.corning.com/opcomm/en-US/catalog/ProductDetails.aspx?cid=&pid=17929&vid=18219)
If you use a mechanical splice, you need a high quality cleaver
just like with fusion splicing and after several uses, you need
to add more index matching gel or liquid - mineral oil works OK.
See
the FOA page on Testing
Bare Fiber.
Is A Flashlight Test Adequate?
Q:
I contracted a firm to install an OM3 of 200 meters. On
one end I have an SFP 1000SX ,on the other a 1000SX
converter from optical to UTP. We made pings but they never
reached, and I didn’t see the laser at the extreme of the fiber.
They promised me to send me the certification they supposely
made ,though they assured me the fiber is ok, because WITH
A FLASHLIGHT THEY SENT WHITE LIGHT FROM ONE SIDE TO THE OTHER
AND IT WAS VISIBLE. I saw the light too, and I thought the
culprit was my switch or my SFP. I want to know: is this a good
demonstration that the fiber is ok?
A: A visual continuity
test is not adequate - your eye is not calibrated! The power of
the lamp is unimportant as each eye’s sensitivity is different.
And your eye probably cannot see the light from a 850nm VCSEL
source - most people’s eyes are not sensitive at that infrared
wavelength. The installer should have tested the link with a
light source and power meter (http://www.thefoa.org/tech/ref/testing/test/OFSTP-14.html)
and given you the loss in dB. The connectors should also be
inspected with a microscope to ensure proper polishing and
cleanliness
(http://www.thefoa.org/tech/ref/testing/test/scope.html). If the
SFP output is -6dBm, what is the power at the receiver?
1000base-SX is supposed to work with 4.5dB loss (see
http://www.thefoa.org/tech/Linkspec.htm). The fiber loss should
be ~0.6 dB, so you must have >4dB connector losses! That says
bad installation! The 1000SX link should work over 200m if the
fiber has been properly installed.
Older Fiber?
Q: I have some 62.5 mm and sm inside fiber plant over
20 years old. When is a good time to upgrade?
A: When you need to or
have to. If it's working OK, there is no need to upgrade!
"Connector Loss" or "Connection
Loss"
Q: I have always counted the loss of a connector as .75
dB (568B-3) and 1.5 for a mated pair. Is that correct?
A: While the industry
always says "connector" loss, it is actually "connection" loss.
As we explain in the page on termination and splicing (http://www.thefoa.org/tech/ref/basic/term.html)
When we say "connector" loss, we really mean "connection" loss -
the loss of a mated pair of connectors, expressed in "dB." Thus,
testing connectors requires mating them to reference connectors
which must be high quality connectors themselves to not
adversely affect the measured loss when mated to an unknown
connector. This is an important point often not fully
explained. In order to measure the loss of the connectors
you must mate them to a similar, known good, connector. When a
connector being tested is mated to several different connectors,
it may have different losses, because those losses are dependent
on the reference connector it is mated to."
The
TIA spec of 0.75dB is for a mated pair of connectors. If you
have been passing connectors tested @ 1.5dB loss....you may have
some very bad connectors in your cabling!
Microscope
Magnification (11/13)
Q: I am doing a lot of fiber optic jumpers for control
systems, either single mode or multimode. I want to get a
scope to inspect the ends after I clean them would you recommend
a 200X, 400X handheld or one similar to a Noyes OFS 300
200C?
A: We prefer to use
lower magnification and have a wider view so I can see more of
the ferrule to determine its condition. You can see the fiber
effectively at 100X but 200X may be better. 400X may be too much
for most tasks like inspecting for cleanliness, but may be good
if you are polishing SM for good reflectance. We've used the
Westover units for years because they offer two different
methods of illumination - direct and at an angle. If you are
doing a lot of patchcords, I recommend a video microscope. I've
used the Noyes unit that interfaces to a PC to create the FOA
Microscope Inspection YouTube video here: http://www.youtube.com/watch?v=IyumH8CiUPQ&feature=youtu.be
and it works well.
Recycling Cabling
Q: Who can I contact regarding recycling cable I am
removing from a building?
A: Here are some people
who say they recycle fiber optic cable or at least know how to
do it:
http://www.scottrecycling.com/complete.html
http://www.scrapmonster.com/selloffer/fiber-optic-cable/10400
http://www.dnvkema.com/services/ces/hse/recycling/recycling-cables.aspx
http://tmscrapmetals.com/Recycling.html
Tech
Hint: Did You Know You Have A Fiber Optic Tester In Your
Pocket?
Yes!
That old mobile phone has a camera which may be 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 sent us some photos showing how
this works. See below
or the video
now on YouTube. Update: You should check out your old
cell phones before you recycle them. We've found older models
use sensors which are better at infrared than the newer ones
which take better pictures. This is a good use for your old
cell phones hiding in the drawer!
Fiber
Cleaning
This is a topic we keep reminding everybody about, and here is
why:
From
a contrator in the Middle East: Here some samples of the
connectors for SM fiber already installed in the system we were
testing.
As
you can see, the dirt is large compared to the size of the fiber
(dark gray), and the core (not visible here) is only 9/125 of
the overall diameter of the fiber!
Clean
Every Connector - A Lesson We Learned From Creating Lessons
In creating
the fiber
characterization
curriculum, we got inputs from many experienced techs about the
testing requirements. Everyone we talked to made a big point
about cleaning and inspecting connectors before testing. Dirty
connectors are a major problem with errors in testing. We've
also seen that many installers think that if a connector,
especially new connectors, has a "dust cap" on the connector, it
does not need cleaning. WRONG!
The common name for the plastic caps on connector ferrules is
"dust cap" and a friend says they
are called "dust caps" because they are full of dust.
Those plastic caps are made by the millions, popped out of
plastic molding machines into barrels and stored until put into
plastic bags. Whenever you remove one of them, clean the
connector before testing or connecting it.
More on connector cleaning is here and here.
More
on cleaning. See Product
News below for links to vendors of fiber cleaning products.
What
You Need To Know About Fiber Optic Cleaning And More
Ed
Forrest, one of the industry experts on cleaning fiber optic
connectors, retired about a year ago. We encouraged him to put
down on paper what he knew about fiber cleaning and he took our
advice. He's now created 4 books on cleaning topics that cover
just about everything you need to know. And he added another
volume that's also important - maintaining fusion splicers. We
recommend these books highly.
How to Precision Clean All
Fiber Optic Connections
Understanding Cross-Contamination Points on Fiber Optic
Inspection & Test Equipment
Maintaining a Fiber Optic Fusion Splicer
Comparison Study of Precision Cleaning Methods for All Fiber
Optic Connection
Whitepaper: The Significance to Optical Internconnect:
Properly Cleaning a Fiber Optic Connection
Information on Ed's books is at http://fiberopticprecisioncleaning.com/available-books-whitepapers/.
See
news about Fiber Optic Cleaning Videos on YouTube by ITW
Chemtronics below.
Fiber Optic Cleaning Videos on YouTube
See news about Fiber Optic Cleaning Videos on YouTube by ITW
Chemtronics three fiber optic cleaning videos on YouTUbe
covering Dry
Cleaning, Wet-Dry
Method, FiberWash
and Combination
Cleaning. They are good explanations of cleaning processes
- the Wet-Dry is especially interesting.
Measurement
Uncertainty: Everyone testing fiber optics should understand
that every measurement has some uncertainty - whether you are
measuring loss, length, wavelength, power, etc. Knowing that
uncertainty is very important to interpreting the measurement.
It's worthwhile to read and understand the issue of measurement
accuracy covered in this
page of the FOA Online Fiber Optic Reference Guide.
RETURN
TO INDEX
Worth
Reading or Watching:
Sign
up at the FOA Pinterest
board
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
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).
Demystifying
Singlemode Fiber Types
Singlemode
fiber has a lot of names and users are confused by the different
names depending on the standards organization you refer to IEC,
ITU or TIA designation. Most widely used are the ITU G65X
designations but even there we find many designations. Shaun
Trezise of M2FX has posted a simple explanation on the company
blog that helps explain the different types and where they are
used. Read
more on the M2FX blog
There is a cross
reference to the IEC, ITU and TIA designations on the FOA
Guide.
EXFO
Offers Super Posters And More
EXFO offers some super posters, guides and books. The FTTx and
OTDR posters are really useful! Look
at the whole selection here.
Getting Cables Out Of Conduit
Usually we are concerned about reducing friction when pulling
cables through conduit, but sometimes you need to get them out.
Here
is a page from American Polywater the leading lubricant
company with advice on the subject.
What Is The FOA?
Hear FOA President Jim Hayes tell the FOA Story in a 2-part
interview by Sound & Video Contractor Contributing Editor
Bennett Liles. It tells about the FOA history, goals and
achievements.
Part 1: http://svconline.com/podcasts/audio/fiber_optic_association_part1/index.html.
Part 2 http://svconline.com/podcasts/audio/inside-fiber-optic-association2-0924/index.html.
What
Happens To Old Fibers?
In a recent web search, we found this article from Corning,
reprinted from a IWCS presentation in 1995. It discusses
extensive tests on a 1984 cable installed in the northern US to
see how it had degraded in almost 10 years. It is interesting to
see how the fiber survived OSP exposure. Read
it here.
Australia's
Standard Is Comprehensive Guide To Customer Cabling (Get your
copy free)
In
answering a recent technical questino, Trevor Conquest in
Australia pointed to the Australian Standard "Installation
Requirements For Customer Cabling." When we checked, it is on
the web and can be downloaded. It's a big book - 220 pages -
full of details for fiber and copper installations. We recommend
you download
yourself a copy - go here.
Demystify
fiber inspection probe technical specifications -
From EXFO
The
intent of this application note is to promote a better
understanding of video inspection probe specifications and
features. Properly understanding the key specifications
and features will greatly facilitate the decision process
involved in acquiring such devices. Understanding the key
aspects of fiber inspection probes will also help users
understand how fiber inspection probes operate, thus
enabling them to maximize the full potential of these
devices. Read
more.
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
http://www.neca-neis.org
(See “State Regulations”)
http://www.neca-neis.org/state/index.cfm?fa=state_regs
(all electrical licensing)
Low Voltage: http://www.neca-neis.org/state/index.cfm?fa=specialty_licensing
How Is
Fiber Manufactured?
OFS invites you on a tour of their multimode fiber manufacturing
facilities in this new 5-minute video. You will see their highly
automated manufacturing operation in Sturbridge, Mass.,
including their patented MCVD preform fabrication process to
fiber draw and final product testing. With a technological
heritage dating back to AT&T and Bell Labs, OFS has been
manufacturing high-quality multimode fiber since 1981.
Watch
the video here.
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.
Fiber
Optic Cleaning Videos on YouTube
ITW
Chemtronics has three fiber optic cleaning videos on
covering Dry
Cleaning, Wet-Dry
Method, FiberWash
and Combination
Cleaning. They are good explanations of cleaning processes
- the Wet-Dry is especially interesting.
-
- Download
yourself a copy and read it!
-
Good
Technical Website For Installers
American
Polywater (http://www.polywater.com/)
has one of the best technical website for cable installers. Check
out their website, especially “Videos,” “Engineer’s Corner”
and “Calculators.” http://www.polywater.com/NNNBSL.pdf
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.
RETURN
TO INDEX
-
FOA
Tech Topics -
A
Fiber Optic Tester In Your Pocket? (See the video on
)
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.
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.
RETURN
TO INDEX
Product
News
YOKOGAWA
OTDR Has Extended range, High Resolution And Multitasking
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!
Recycling Communications Cable
FOA was
contacted by a company that recycles electronics communications
equipment and cabling. CommuniCom recycles
cable/metals/e-waste
for Telcos and CATVs. They also recycle Fiber Optic Cable and
associated Materials (the fiber scrap). And, they reclaim OSP
abandoned copper cables (abandoned from road moves or FTTx
growth). This is a huge part of our business. They do the work
(permitting/locates/labor) for free and we revenue share back
with our clients (telcos).
Contact
Steve Maginnis
smaginnis@communicominc.com
www.communicominc.com
803.371.5436 (cell)
Micro-Trenching, Cable
Removal
Nano-Trench
offers products for micro (or I guess they call it nano-)
trenching and their
website is very informative. They also have Kabel-X,
a method of extracting copper cables from old conduit. Both
websites are informative and interesting. Watch
this video on the cable removal process!
Protecting Pedestals From
Rodents
Pedestals
and underground vaults can be damaged by rodents who come up
through the base and damage cables. Uraseal "Drain N'Seal"
foam deters mice from taking up residence in your pedestals. They
have some good videos on using their product.
Used
Test Equipment – Buy or Sell
http://www.testequipmentconnection.com/
Have
you read the FOA
pages on cleaning?
- RETURN
TO INDEX
FTTH
Notes:
- Want
To Learn More About FTTx? Try our free online self-study
program at Fiber
U.
|
