In-service monitoring of 16 port x 32 wavelength bi-directional WDM-PON systems with a tunable, coded optical time domain reflectometry

Abstract

We propose a multi-port, multi-wavelength supervisory system for the in-service transmission line monitoring of a bidirectional WDM-PON system. Identifying unique requirements for the performance monitoring of a real field WDM-PON system, we define the architecture for the supervisory system and utilize the most up-to-date technologies (Simplex coding, tunable source, and optical switches) to demonstrate a successful interrogation of a transmission line up to 16 ports x 32 nodes (512 user) capacity. Monitoring of individual branch traces up to 60 km was achieved with the application of a 127-bit simplex code corresponding to a 7.5dB SNR coding gain. In-service transmission experiments showed negligible penalty from the monitoring system to the transmission signal quality, at a 2.5Gbps / 125Mbps (down / up stream) data rate.