Protection of WDM PON systems based on modified 2-OLT architecture

In this paper, we propose a novel protection architecture of passive optical network (PON) system. Two optical line terminals (OLTs) are connected to each other as well as to the access area. This network can sustain services to access area and restores normal operation in faulty conditions. Subscribers are divided into two groups to reflect priority based bandwidth allocation. WDM access increases the efficiency of the system by operating both OLTs using different wavelengths in normal condition. During fault, a Shared-bandwidth allocation scheme is employed in operating the survived OLT. Performance analysis shows the improvement of the proposed scheme over an existing scheme.