OTDR in Optical Amplifier Transmission Systems Using EDFAs Containing Optical Circulators

Abstract

Optical time domain reflectometry (OTDR) is an effective technique for locating breaks and for determining the loss distribution along a fiber [1][2]. However, OTDR can not be used with optical transmission lines containing traditional Er-doped fiber amplifiers (EDFAs) because EDFAs require optical isolators to eliminate signal reflection [3]-[5]. The returning backscattered light generated by the forward traveling probe pulse is blocked by optical isolators in each EDFA.