Efficient and Reliable Protection Mechanism in Long-Reach PON

Network survivability and protection mechanisms are very important and necessary in optical networks. The long-reach passive optical network (LR-PON) proposed in this paper extends the access network to hundreds of kilometers, and it can support more optical network units by wavelength division multiplexing technology. We propose an efficient protection mechanism for the whole LR-PON. Optical encoders are used to monitor the whole network, and a network management system in the central office will initialize the protection process by monitoring the information it collects. When the network works normally, space division multiplexing technology is adopted to reduce the loss and crosstalk of signals. The designed system propagates the upstream and downstream signals in different fiber rings to mitigate the influence of Rayleigh backscattering. The proposed protection mechanism can protect the network from the multi-faults of fiber links with the designed switches. Furthermore, the loss, availability, costs, and network performance are also studied. The results obtained prove the feasibility of the proposed network. The network is costless and reliable, and it has high availability of up to 99.9992% by the protection mechanism.