Broad area optical debris impact sensor

摘要

Fiber optic sensors offer many advantages over electrical sensors for use in harsh environments. One advantage over distributed electrical sensors is the elimination of the need to route electrical power and wiring to the sensors, which, in general, improves safety and reduces power consumption. Another advantage is that the optical sensors are immune to electromagnetic interference that may be caused by radio frequency signals used for communications. Another benefit of using an optical approach for impact detectors is the implicit immunity from false detections that may otherwise be caused by unrelated mechanical shock or vibration events. Previous studies have documented the characteristics of the Optical Debris Impact Sensor (ODIS). With the ODIS, the impacts are inferred by detecting the brief triboluminescent optical pulses generated by the abrupt charge separation within a phosphor that is caused by the particle impacts. The main limitations of the ODIS are the small detection area and the limited sensitivity. This paper describes a method for extending the ODIS to accomplish broad area detection on a surface with potentially higher sensitivity. The sensing element is comprised of a stack of planar optical waveguides with phosphor-coated strips. The geometry of the design ensures optical pulses are automatically captured by the waveguides and routed to a fiber optic cable that transports the signal to a remote high-speed photodetector. Background light levels in the vicinity of the detector are filtered out by the tailored frequency response of the photodetector.