Detection and location of the gain variations in an optical repeater chain

A method is proposed that allows the detection and location of the gain variations generated in any section of an all-optical link formed by a set of fiber and optical-amplifier (OA) sections. The proposed method is shown to be a powerful and simple solution for the supervisory system of a link with optical amplification. It is suggested that this method can facilitate the practical application of the OA in long-haul transmission systems. By computer simulation of the optical link and the supervisory system, the accuracy of the method has been shown. Different error sources, the quantum and receiver noise, the saturation of the OA, and the possibility of nonidentical sections were taken into account. This has led to the proposed configuration of the supervisory system that detects and locates failures of the optical link