Optical Fiber Attenuation Measurement

Abstract

<p> Optical fibers are becoming so good that their optical and mechanical properties are fast approaching fundamental limits. It has also become evident that there is a requirement for establishing accurate and precise measurement techniques of these properties. The optical loss is the most important parameter characterizing fiber. This project reviews the subject of loss (or attenuation), its measurement and some of its subtleties. </p> <p> Presently at BNR there are two attenuation measurements made: (1) one is the LED steady-state attenuation at λ≅840 nm, which makes use of a "pigtail" launching fiber and (2) the second is the spectral attenuation from 600-1400 nm. Both measurement techniques were developed by the author and Dr. K. Abe during the summer work term and made considerable improvements in both accuracy and speed over previously established methods. Some of the subtleties of attenuation which were also studied during this period were the effects of different launch conditions, and environmental effects such as those caused by temperature and ice. The extensive temperature tests done on the fiber led to the change from "hytrel" and nylon as coating materials to the use of silicone (which is still in use at BNR).</p> <p> Throughout the paper, results of the measurements have been given for several types of fibers because some of them have very unique characteristics and applications. </p> <p> All of the data displayed for this project was gathered by the author unless otherwise noted.</p>