Fiber-optic semiconductor absorption temperature sensor for electrical power system applications

A fiber optic semiconductor absorption sensor for temperature measurement is presented. The sensor is based on the temperature dependence of band gas edge absorption of infrared light in semiconductor, and made of multimode optical fiber in light reflected from a GaAs semiconductor platelet configuration. The configuration reported here is small, easy to handle, and a fast response time. A light emitting diode are used as sources of analytical and reference radiations, which eliminates the influence of intensity fluctuation of the light source and that of the coupling and connecting loss of optical fibers. The sensor features the accuracy of 1/spl deg/C over a temperature range from -20/spl deg/C to 110/spl deg/C, and response time of 0.23 s//spl deg/C. The sensor is particularly suitable for temperature measurement in electrical power systems.