X-shape optical fiber pressure sensor constituted by a single-mode optical fiber directional coupler with a reflecting end face

摘要

Abstract: An X-shape optical fiber pressure sensor has been proposed. The sensor is constituted by a single mode optical fiber directional coupler, at one output end of which a layer of Al-film is evaporated. The output fiber with Al-film covered end serves as a sensing element and self-reference arm as well, and the other to monitor the instability of light source. One of two input ends of the directional coupler acts as an input end of the sensor, another as an output end of the return light signal from the Al-covered output end of the coupler. In principle, the sensor is based on polarization interference caused by transverse pressure. From the normalized intensity of the output light beam and its rotation angle, the pressure can be determined, ranging from 0 to 120,000 dyne/cm. !5