PCF-based Fabry-Perot refractive-index sensor

摘要

This paper, for the first time to the best of our knowledge, presents a novel fiber-optic refractive-index sensor which is based on an intrinsic Fabry-Perot interferometer (IFPI) formed by a section of endlessly single-mode photonic crystal fiber (EPCF) and conventional single-mode fiber. Such an IFPI sensor has the advantages of easy fabrication, low joint and transmission losses, low-cost and good fringe visibility due to the use of the EPCF. Simultaneous measurement of refractive index (RI) and temperature can be realized by determination of the cavity length change and the fringe visibility of such a PCF-based IFPI, respectively. In addition, it is found that the fringe visibility of the IFPI is insensitive to temperature change, providing a practical way to measure refractive index with self temperature compensation. Such a miniature fiber-optic sensor is demonstrated for the measurement of the refractive index change of glycerin solution by measuring its fringe visibility change solely.