Optical fiber temperature sensor using wavelength detection

A wavelength demodulation technique was proposed based on the polarization mode interference in polarization maintaining optical fiber (PMF), and the sensing equation was obtained. The temperature linear to the reciprocal of the interference fringe's period which is defined as space frequency. It simplified the test procedure. In the experiment, the performance of the tunable optical fiber Fabry-Perot filter was demonstrated and the linear relationship between the drive voltage and the permissible wavelength was obtained. The optical spectrum was obtained by the tunable optical Fabry-Perot filter instead of the optical spectrum analyzer. It simplified the experiment equipment. The test method is independent of the power floatation of the light source and just related to the wavelength information. This wavelength demodulation technique overcomes the effect of the light source power fluctuation and the variation of optical loss that occurs in the transmission fiber. The adaptability of optical fiber temperature sensor is enhanced.