Category Archives: Fiber Optics

Laser Slope Efficiency and Curve Fitting

Posted on August 23, 2012 by

Introduction I have spent much of my summer dealing with issues related to the high temperature characteristics of lasers. These issues have stirred within me an interest in laser slope efficiency .  Slope efficiency, also known as SE,  is simply … Continue reading →

Posted in Electronics, Fiber Optics | Tagged | Leave a comment

Laser Tracking Error and Curve Fitting

Posted on August 23, 2012 by

Introduction I had a request for an example of how the output power of a laser varies with temperature. We call this parameter tracking error. Tracking error varies from part to part and the manufacturers simply put a bound on … Continue reading →

Posted in Electronics, Fiber Optics | Tagged | Leave a comment

A Little Specification Reading Before Bed

Posted on April 25, 2012 by

Introduction Nothing like reading ITU optical specifications to help you get to sleep after an active day. Since I have been doing some work on dispersion, let’s pull up ITU G.695 – Characteristics of Optical Systems. I want to see … Continue reading →

Posted in Fiber Optics | Tagged , , | Leave a comment

Optical Fiber Dispersion Formula – Where Did This Come From?

Posted on April 22, 2012 by

Introduction Most Fiber-To-The-Home (FTTH) deployments in North America use SMF-28e fiber from Corning, which is to fiber what Kleenex is to tissue. Unfortunately, I am so familiar with this particularly product that I can recite its specifications from memory. However, … Continue reading →

Posted in Fiber Optics | 2 Comments

Some Laser Basics

Posted on December 14, 2011 by

Introduction I am doing some interesting work with lasers this week. I thought it would be useful to provide some background on how we build and control lasers. We deploy a lot of lasers in outdoor applications, which means that … Continue reading →

Posted in Electronics, Fiber Optics | Tagged , , | 4 Comments

The Power of a Simple Magnifying Glass

Posted on May 17, 2011 by

Introduction My favorite radio program is Science Friday. Last week, their web page included an excellent video where Science Friday’s resourceful intern, Flora Lichtman, gave a wonderful explanation behind the use of a lens to concentrate the Sun’s power. Her … Continue reading →

Posted in Astronomy, Fiber Optics | Leave a comment

Test Time and Estimating Bit Error Rate

Posted on December 26, 2010 by

Introduction Test time is expensive. Since our products need to conform to industry standards for Bit Error Rate (BER), we need to test for BER. It is important that we test long enough to ensure that we meet the requirements, … Continue reading →

Posted in Electronics, Fiber Optics | Tagged , , | 4 Comments

Laser Failure Rate Estimate Example

Posted on December 5, 2010 by

Introduction I have spent some time lately talking to people about laser failure characteristics. Most electronic component reliability modeling is done using the exponential probability distribution, which assumes the components have a constant failure rate and there is no wearout … Continue reading →

Posted in Electronics, Fiber Optics | Tagged , , | 2 Comments

Magic Number Analysis – Converting Spectral Width to Sigma

Posted on October 12, 2010 by

Introduction Engineering seems to have a lot of “magic numbers” – numbers used in equations with no explanations of where they come from. I REALLY do not like magic numbers because years from now some other engineer will be staring … Continue reading →

Posted in Fiber Optics | Tagged , , , | 3 Comments

Dispersion Power Penalty Modeling (Part 3)

Posted on October 8, 2010 by

Deriving Equation 2 Equation 2 is derived from Equation 7 by noting the following items. A true normal pulse has infinite length, so we cannot have a high speed data system that sends true normal pulses. A common choice is … Continue reading →

Posted in Fiber Optics | Tagged , , | 2 Comments