Narrow Band Optical Receiver Based on a Thermally Tuned Optical Bandpass Filter

Optical fuzing of munitions using laser diode sources offers several advantages over competing technologies. These include covertness compared with microwave technologies, very high directionality, and lightweight, compact components. One serious disadvantage of laser diode fuzing for systems requiring daytime operation is the need for temperature stabilization of the laser diode when the receiver contains a narrow bandpass filter. The additional power, weight, size and complexity oflaser diode thermal stabilization precludes its use in many situations. The program proposed here addresses these problems by designing and building a bandpass filter with high thermal shift, which is matched to the laser diode. The thermal shift will be achieved by intrinsic thin-film material properties. This allows the bandpass of the filter to track the laser diode without thermal stabilization and its attendant complexity. The filter is passive in that no power sources are required for tuning. The Phase I effort will study materials and procedures to build the filter, including experimental verification of key thermal and thermooptic properties.