A practical in-service supervisory technique using reflected-pulse detection based on OTDR for optically amplified passive branched CATV networks

We propose and experimentally demonstrate an inservice supervisory technique based on reflected-pulse detection, which can simultaneously monitor the performance of all active network devices (such as optical transmitter, optical amplifiers, and optical receivers) and locate the fiber fault in optically amplified passive branched cable TV networks by using a conventional optical time-domain reflectometer (OTDR) combined with 1/spl times/2 optical switches. The monitoring parameters such as required dynamic range of OTDR, response time, and the maximum number of monitoring transponder elements are discussed.