Coherent Optical Frequency Domain Reflectometry as Characterisation Tool for S-Band TDFAs

Optical frequency domain reflectometry (OFDR) is an interferometric method which allows to determine the spatial distribution of the gain along the active fiber in a fiber amplifier. As a non-destructive tool it is ideal to find the optimum fiber length especially of co-directional pumped fiber amplifiers. In this paper we explain the OFDR method and discuss measurement results from different S-band TDFA setups.