Research on a Novel Fabry⁻Perot Interferometer Model Based on the Ultra-Small Gradient-Index Fiber Probe.

A novel Fabry⁻Perot (F⁻P) interferometer model based on the ultra-small gradient-index (GRIN) fiber probe is investigated. The signal arm of the F⁻P interferometer is organically combined with the ultra-small GRIN fiber probe to establish the theoretical model of the novel F⁻P interferometer. An interferometer experimental system for vibration measurements was built to measure the performance of the novel F⁻P interferometer system. The experimental results show that under the given conditions, the output voltage of the novel interferometer is 3.9 V at the working distance of 0.506 mm, which is significantly higher than the output voltage 0.48 V of the single-mode fiber (SMF) F⁻P interferometer at this position. In the range of 0.1⁻2 mm cavity length, the novel interferometer has a higher output voltage than an SMF F⁻P interferometer. Therefore, the novel F⁻P interferometer is available for further study of the precise measurement of micro vibrations and displacements in narrow spaces.