Microwave Interrogated Sapphire Fiber Michelson Interferometer for High Temperature Sensing

We present, for the first time to our knowledge, a microwave interrogated sapphire fiber Michelson interferometer for high temperature sensing. By sending a microwave-modulated optical wave to a sapphire fiber Michelson interferometer, a high quality interference spectrum was reconstructed in the microwave domain with a fringe visibility exceeding 40 dB. The sensor showed good sensitivity, reversibility and stability in the temperature range of 100 °C-1400 °C. The proposed sensing configuration has a number of unique advantages including low dependence to the multimodal influences, high signal quality, relieved fabrication precision, and insensitivity to the background blackbody radiation when used in high temperature.