Transparent supervision of optically amplified fibre links with received signal and ASE monitoring

This paper illustrates that remote fault localisation in all-optical links with concatenated fibre amplifiers can be performed by simple monitoring of the signal and the accumulated ASE noise powers at the receiver end. The m ethod is first presented in ideal operating conditions, and second, the eff ect of the spontaneous emission factor variation and the EDFA non-linear be haviour are taken into account. From the analysis, the requirements of the link design for proper supervision accuracy are derived. The presented supe rvisory method is a simple solution for links where a fibre break or an amp lifier fault is to be detected and located with the granularity of an ampli fier section without local supervisory elements within the transmission sec tions. (C) 2000 Published by Elsevier Science B.V.