Optical Fiber Bus Protection Network to Multiplex Sensors: Amplification by Remotely Pumped EDFAs

We report a physical-layer study of an optical fiber network for the multiplexing of sensors that can regain service after damage to its fibers. It is a symmetrical dual-fiber bus that uses “dedicated-line” or “dedicated-path” protection switching in response to a failure. Amplification is normally needed when serving more than $\sim$10 sensors, even when the network's directional couplers are optimized, and we simulate the use of remotely pumped spans of erbium-doped fiber to eliminate all electrical power feeds outside the end nodes. Our description of the network's management and signaling and its actions in response to a failure emphasizes the amplifier pump control. We model a network with dedicated-line protection to serve 40 sensors, showing that good channel power equalization and signal-to-noise ratios are possible by carefully optimizing the erbium-doped fiber lengths and including gain-equalizing filters.