Development of Equilibrium Mode Distribution (EMD) in a Fiber - A Characterization of the Transient Behavior and Steady State Mandrel (SSM) for Corning Data Broadband Fiber (dBF)

Abstract

Contained in this paper are empirical results leading to a better understanding of the development of a steady state power distribution in an optical fiber, commonly referred to as Equilibrium Mode (Power) Distribution (EMD). First, three terms are defined and the importance of their measurement given: Transient Loss, Steady State Mandrel (SSM) Prescription, and Mode Power Distribution (MPD) Measurement. Second, the results of the transient loss testing and the mandrel wrap experiment, which determined the SSM (a mandrel which can be used for convenient attenuation measurement), are given for 85μm core fiber (Corning Data Broadband Fiber (dBF)). Third, MPD measurements verifying the conclusions drawn concerning the establishment of EMD or steady state are given as a function of fiber length and for various launch conditions.This paper has two primary conclusions. First, by actual measurement of the relative mode power distribution in sample fibers, steady state or EMD has been shown to have been established. Second, a mode filter in the form of a mandrel around which the sample was wrapped five times has been chosen such that the steady state power distribution was reproduced.