Category Archives: Fiber Optics

Chromatic Dispersion with 10 Gigabit Optical Transports

In this post, I will be showing how we model the effect of small amounts of dispersion as a power loss. We commonly refer to this power loss at the dispersion power penalty. I will also show how the need to limit the power penalty drives a critical laser parameter, the laser spectral width. Continue reading

 
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Fiber Optic Cable and Lightning

Lightning is a tough problem. All of my personal electronic systems are well grounded and have the best surge protection I can buy. Yet I still suffer occasional losses due to lightning – for example, this weekend I replaced a surge-blown power adapter at my cabin in northern Minnesota. Intuitively, you would think that fiber optic systems should be better protected against lightning strikes than copper-based systems because glass fiber does not conduct electricity. This is not necessarily true. Continue reading

 
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Typical Field Deployment Issues

I was looking at some photographs of a fiber-optic deployment, and I thought you might find it interesting seeing the details of what goes into the "green yard furniture" that quietly sits in the yards of many people (Figure 1). The fiber electronics is slung on a metal bar above the hole in the ground – all the cabling comes up from the hole. The plastic green cover behind the hole is intended to provide some environmental protection and a decent appearance. Continue reading

 
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I am Battling Ladybugs This Year

We have had a warm winter in Minnesota so far this year. As with every transition from fall to winter, bugs seek warmth by taking up residence in our fiber-optic enclosures. Here is my latest example, a ladybug on a returned circuit board. Continue reading

 
Posted in Electronics, Fiber Optics, Humor | 4 Comments

Passive Optical Network Fiber Length

I recently was asked to explain how a Fiber-To-The-Premises (FTTP) system measures the length of fiber between the central office and each residence in the network (Figure 1). This is an interesting question and I thought it would be worthwhile to the describe the measurement process here. Continue reading

 
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Return Loss of a Glass-Air Interface

I received an email today about a deployment issue that involved the reflection of light from unterminated connectors. When light travels down a fiber and encounters a change in the index of refraction, part of the energy will reflect back toward the transmitter because of a phenomenon called Fresnel reflection, which I define below (source). Continue reading

 
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Submarine Fiber-Optic Cable Trivia

I am at the Optical Fiber Conference in Los Angeles this week and learning a lot. This morning I attended a great talk submarine fiber optic cables given by Neal Bergano, CTO of TE Connectivity Subcom. I thought I would put my notes on blog for others to view. I was not able to find a copy of Neal's presentation, so I will replicate my notes on his presentation here. Where possible, I will include supporting information that I located on the web. Any errors introduced are mine. Continue reading

 
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High-Speed Broadband, Fiber-To-The-Home, and President Obama

I have been working for the past 15 years on making Fiber-To-The-Home (FTTH) real in the United States. Yesterday, President Obama visited one of our customers (Cedar Falls Utilities).  Here is a photo of the event. I have put a … Continue reading

 
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Best Fiber Optics Tutorial I Have Seen

If you are wondering about how fiber optics works, this is the best tutorial I have seen.  

 
Posted in Fiber Optics, General Science | 1 Comment

Using a Laser To Deliver Multi-Channel, Broadcast Video

Introduction Everyday, I work on delivering fiber-based, video access equipment to service providers. The increased demand for High-Definition Television (HDTV, Figure 1) has increased the need for fiber in the video distribution network. Today, fiber optic cable is often used … Continue reading

 
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