Full monitoring for Long-Reach TWDM Passive Optical Networks based on TRA technique

Abstract

Long-Reach Passive Optical Networks (LR-PONs) consolidates of metropolitan and access networks by extending the distance between the Central Office (CO) and the end users, which in turn simplifies the network and potentially brings cost savings. With the explosively growing of data traffic, Time and Wavelength Division Multiplexing (TWDM) technology have also been employed in LR-PON to realize high capacity. However, due to high capacity and large coverage, the presence of a single failure may cause a huge loss of data and affect a large number of subscribers in LR-PON. Efficient network fault monitoring therefore becomes a key to improve the level of network reliability. In this paper, we report an advanced solution realizing fault detection, identification and localization in both feeder and distribution fiber segments of TWDM LR-PON. Instead of using the conventional optical time domain reflectometry (OTDR) approach, we implement multi wavelength Transmission-Reflection Analysis (nλ-TRA) as the monitoring technique, which is able to provide a good spatial accuracy and a high detection speed without interfering with the data traffic. Theoretical analysis and experimental validation demonstrate that the proposed scheme is capable of providing an accurate fault monitoring functionality.