Fiber-optic temperature sensor based on internally generated thermal radiation.

This paper presents a theoretical and experimental study of a method of sensing temperature with optical fibers with the radiation thermally generated within the fiber. Using quartz fibers it is possible to read temperatures in the range from room temperature to over 1000 degrees C. We have demonstrated operation as low as 135 degrees C using nonoptimum fibers and detectors. The method also allows the determination of the location and length of a hot spot along the fiber. The purpose of this type of sensor is to monitor the development of hot spots in electrical machinery, such as generators and transformers, where conventional measurement techniques cannot be effectively applied. If such optical fibers can be incorporated in the manufacturing process of electrical equipment, these temperature monitors may contribute in avoiding catastrophic breakdown.