Research progress of in-fiber Fabry-Perot interferometric temperature and pressure sensors

Optical fiber sensors based on Fabry-Perot interferometer (FPI) have attracted intensive attention for sensing applications in temperature and pressure measurement, owing to their compact, small size, fast responses, high resolution, high sensitivity, good stability, and resistance to electromagnetic interference. It's known that the in-fiber optic interferometers based on single-mode fibers can exhibit compact structures, easy fabrication and low cost. In this paper, firstly, the basic principle of in-fiber FPIs is introduced. Secondly, we review several kinds of typical in-fiber FPIs formed in single-mode fibers fabricated with different post-processing techniques, such as chemical etching, arc discharge, femtosecond laser micromachining, and polymer coating, etc. Finally, the optical sensors based on in-fiber FPIs, with a capability of simultaneous multi-parameter sensing of temperature and pressure, are summarized and prospected.