In-service fault locating and supervisory CATV optical distribution network using WDM-based OTDR and optical switches

摘要

We demonstrate an in-service fault-locating and supervisory technique for multi-staged CATV optical distribution networks. The requirements of ultra-high dynamic range of an optical time domain reflectometer (OTDR) to diagnose the network can be tremendously relaxed by the introduction of optical switch and wavelength-division-multiplexing (WDM) technique. Any faults of the fiber links whether before, after, or between optical splitters can be located. The system operation is experimentally demonstrated in a two- staged eight-optical-node CATV distribution network. The degradation of system performance of carrier-to-noise ratio, composite second order, and composite triple beat due to in- service OTDR operation can be neglected. This surveillance system can provide real-time testing, saving the cost of dispatching a technician to perform routine testing and reducing the time taken to identify faults after an outrage occurs.