All-Passive Optical Fiber Sensor Network With Self-Healing Functionality

An all-passive optical fiber sensor network is proposed based on a novel single-line bidirectional optical add-drop multiplexer (SBOADM). By reasonably employing fiber Bragg gratings and optical circulators to compose the self-developed SBOADM, single-line bidirectional transmission can be easily achieved by the SBOADM without the assistance of a power supply or optical switch. Experimental results prove that when optical signals are fed into the proposed SBOADM in clockwise or counterclockwise direction, the insertion loss of the dropped optical signals is roughly 3.7 dB or 4.5 dB, respectively, and the attenuation of each added signal is about 3.6 dB. When the SBOADM is employed to bridge a hybrid tree-based and ring-based optical fiber sensor network, self-healing functionality can be easily embedded into the network. Once an interruption occurs in the network, the only thing that the system maintainer needs to do is to adjust one optical switch pre-installed in the remote node of the sensor network. Simulation results show that the maximum power penalty caused by the self-healing function is roughly 6 dB. That is to say, the proposal can easily overcome any one fiber-link failure without adjusting the network deploying setting or employing complex control management.