TEMPERATURE SENSOR

摘要

PCT No. PCT/GB84/00138 Sec. 371 Date Dec. 18, 1984 Sec. 102(e) Date Dec. 18, 1984 PCT Filed Apr. 24, 1984 PCT Pub. No. WO84/04385 PCT Pub. Date Nov. 8, 1984.A temperature sensor comprises a single-mode all-fiber Michelson interferometer. The interferometer includes a bi-directional coupler and signal and reference fibers having mirrored ends. These two fibers are of unequal lengths to provide an optical path length in-balance and the signal fiber may have a metal temperature sensing probe at its mirrored end. The injection current of a laser light source for the interferometer is modulated with a ramping signal so that a linearly moving interference pattern is produced at the output by mixing of the reflected beams propagated in the signal and reference fibers. The interference pattern is monitored by a photodetector and electronic circuitry processes the output of the photodetector to determine the optical phase shift between the light beams propagated in the signal and reference fibers, which phase shift is dependent on expansion or contraction of the signal fiber with respect to the reference fiber and is therefore related to the temperature at the sensing probe.