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Instructor Corner

May 2020
Chicago Deep

Most underground, terrestrial fiber optic cable infrastructure is only several feet below grade. However, there is one network in particular that is far deeper.  Below the streets of Metropolitan Chicago is an extensive tunnel system that is about forty feet below the street level.

February 2020
Closing the Fiber Expertise Gap

Hiring subcontractors not only closes a manpower gap on large projects; it also closes an expertise gap. Subcontractors and consulting engineers often have skills that the operating company does not.A familiar example might be hiring a consulting engineer to draw up system plans or draft a Statement of Work. 

December 2019
Hiring and Managing Fiber Contractors for a Successful Project

All communications networks experience a life cycle. They are planned, designed, procured, installed, provisioned, and maintained. Throughout their life they experience degradation, technology changes, and likely equipment/technology obsolescence. Due to these changes and others required by market forces, the cycle must sometimes be repeated from its beginning.

October 2019
“We Ain’t Afraid of No Ghosts!”

Optical time domain reflectometers (OTDRs) are critical instruments for evaluating optical fiber spans. Like any technology, they are not infallible. As the term ‘reflectometer’ implies, OTDRs work by analyzing optical signals which are reflected (and scattered) back to them. Some people call them “cable radar” because they...

August 2019
Fiber Cable to the North Pole

Well, not exactly to the North Pole, but close! 947 miles from the pole, to be precise. In the summer of 1991, as a project manager for a 30-mile cable install at Thule placing Submarine...

May 2019
OTDR Dynamic Ranges

The OTDR is one of the most powerful tools you will purchase to support your fiber network. The informal definition of Dynamic Range is “how far can my OTDR see?” There are at least two formal definitions of Dynamic Range, the...

October 2018
A Primer on WDM-PON

Fiber to the home (FTTH) has been available for some years now and is widely (although not universally) deployed. FTTH technology is still evolving to meet both present and future demands. Technologies such as wavelength division multiplexing (WDM) and time and wavelength division multiplexing (TWDM) have existed for decades, but now...

September 2018
What to Look for in a Cleaver

Many types of cleavers are used in today’s fiber applications — from simple “score and snap” types with carbide or ceramic blades to high-precision automated models with diamond blades.  Determining which of them is best is ultimately dictated by….

August 2018
Launch Cables, Part 2: Using Launch and Receive Cables with an OTDR

Launch Cables, Part 2 discusses the practical use of launch and receive cables in specific testing situations with an OTDR. Part 1 (last month) dispelled some of the myths around launch cables, and explained the basic theory behind their use in testing the near end and far end connectors of a fiber under test (FUT).

July 2018
Launch Cables, Part 1:  What is a Pulse Suppressor?

Launch Cables, Part 1 offers a historical perspective on the need and proper use of launch cables for OTDR testing. Part 2 (next month) will discuss specific testing situations. 

May 2018
Product Registration of Test Equipment — It is Important!

No matter what you purchase these days, manufacturers include product registration cards. Even inexpensive consumer products like Bluetooth head phones and toasters come with product registration cards. The volume of these we see with everyday purchases can drive one to a cynical viewpoint - All they want is to collect contact information for marketing purposes. This is undoubtedly true in some cases. However, test equipment is a different situation.

April 2018
Emergency Restoration Kits: Planning & Preparation

The majority of fiber system outages result from localized damage that only extends 3-5 meters on each side. To limit and reduce the downtime of a cut or damaged fiber optic system, having an emergency restoration kit (ERK) on hot standby is imperative.

March 2018
Advantages of Fiber over Copper

All modern communications systems are based on fiber optic cable – hair-thin (or thinner) strands of glass that carry information by transmitting pulses of light, which are usually created by lasers. 

February 2018
OTDRs Never Go Out of Style

The optical time domain reflectometer (OTDR) is now thirty-six years old and aging gracefully. While fiber optic cables had been installed in North America since 1977, one major concern was and still is: how do we accurately locate a fault? This is the major reason that OTDRs exist. Fortunately, as the communications industry has matured, so has the OTDR. Why use it?

January 2018
OTDRs and Location Accuracy

One of the many reasons to use an OTDR for testing and troubleshooting is to get data about a severe bend or break in your cable plant. The OTDR can provide the location of a break so that you can send out a crew to repair it. But, how accurate is that location?

December 2017
Questions from our Training Classes! -Part II

Our instructors answer a lot of questions. Here are a few of the most common ones.

November 2017
Fiber Optic Questions from our Training Classes!

Our instructors answer a lot of questions. Here are a few of the most common ones.

October 2017
Dirty Connections and Network Problems

What do flossing your teeth, changing your car’s oil, and cleaning your fiber optic network connections have in common?  We know how important it is to do these tasks — but often don’t follow through until something goes wrong! 

September 2017
Fiber Optic Tap Couplers for Low Density FTTx Installations

Maximizing the efficiency of optical line terminal (OLT) cards in passive optical networks (PON) in low-density and rural FTTx installations can be a major challenge. In most PON designs, it is considered ideal to connect 32 subscribers to a single OLT for maximum cost efficiency.

July/August 2017
Optical Loss Testing in a Multimode Network

The accepted best practice for testing link loss in a multimode network calls for the most accurate and repeatable test set up: the one-jumper reference method. 

May/June 2017
Test Cables Don’t Last Forever

I frequently hear customers complain that although nothing has changed in their fiber optic cable assembly production process, the measured Insertion Loss (IL) and Return Loss (RL) values of their product aren’t as good as they once were. Is something wrong with the measurement equipment? Well, it’s possible but unlikely.

March/April 2017
Splitter Types and Configurations

Today’s designers use splitters to passively tap, split, and multiplex optical signals. Since their introduction in the 1970s, splitters have seen their share of technological development, including the use of bulk optics, lenses, and optical fibers.

January/February 2017
A Primer on Optical Amplifiers

Attenuation is major concern in every fiber optic system. The further a digital signal travels, the more its strength diminishes. Every splice, every connector, and even the fiber itself will contribute a tiny bit more to the overall system loss. Fortunately, for spans that are too long or have losses that are too great, a solution exists in the form of optical amplifiers.

October/November 2016
Troubleshooting Non-fiber Related Problems in Your Link

Fiber optic communication systems consist of more than just a physical fiber optic link and troubleshooting must always begin with an examination of the entire network. A technician must look at the big picture to rule out other potential trouble spots before suspecting the fiber or other passive optical components.

August/September 2016
Labor Comparison – Sealed vs. Weather-tight Closures

A few months ago, we published some information about the pros and cons of sealed versus weather-tight fiber optic splice closures (FOSCs). We recently came across some additional information on labor time when having to splice into each type in an aerial installation.

July 2016
Don’t Tell Us Connector Cleaning Does not Matter!

A high-performance fiber optic network requires low attenuation and low reflectance values to obtain the necessary bit error rate level. Unfortunately, all it takes is one contaminated or damaged connector to slow down or disrupt a transmission system.

June 2016
Shedding light on WDM-PON

Although fiber to the home (FTTH) is now considered mature, the industry is still bringing new evolutions of the technology to the forefront. It is critical that designers, planners, and managers know what these evolutions are and how to migrate from a legacy or next generation fiber to the user (FTTx) network.

May 2016
The testing effects of micro- and macrobending of fiber optic links

The proper installation of cables and patch cords and the routing of optical fibers in splice trays is crucial to meet the performance expectations of today’s high-speed fiber optic systems. However, these proper practices can sometimes be forgotten with the emergence of bend insensitive or bend tolerant fibers.

March/April 2016
Optical reflectance, optical return loss and bit error rate

Most installers and operators focus on optical attenuation and dispersion to handle increasing data rates. However, in single-mode systems, reflectance is just as critical to achieve the desired bit error rate (BER).


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