FIBER OPTIC COUPLER SENSORS

A new fiber optic sensor, based on sensitive single mode fused couplers, which has wide applicability to shipboard use, is introduced. Recent tests have shown that these sensors may be used as all optical hydrophones. Other tests have demonstrated that these sensors are useful as very sensitive accele‐rometers such as might be used for active machinery monitoring. Fiber optic coupler sensors can be used as all optical strain gauges as well. These sensors are composed of a potted single mode fused directional coupler which changes its coupling ratio in response to applied stress. The sensor may be designed into many configurations, including devices for monitoring seismic activity, magnetic field, temperature, pressure and other activities. Since the manufacturing technology involved in these sensors is rather simple, straightforward applications allow very inexpensive devices. A unique multiplexing scheme allows single source/single receiver operation of a string of all optical sensors. © 1990 by the American Society of Naval Engineers