UV-induced intrinsic Fabry-Perot interferometric fiber sensors

Abstract

In this paper, we present a novel point-wise laser writing method that utilizes a focused ultraviolet (UV) laser beam and metallic masks to write local Fresnel reflectors and intrinsic Fabry-Perot interferometric (IFPI) sensors in photosensitive fibers. These UV-induced IFPI sensors have features of low reflectance and low power loss and have the potential to be densely multiplexed. We also present a sweeping laser based measurement system that measures the interference spectra and estimates the optical path distances (OPD) of IFPI sensors. We also demonstrated IFPI sensors for temperature, strain and pressure measurement. Laboratory test results show that these UV-induced IFPI sensors can have a resolution of 0.1°C for temperature measurement and 0.5 micro-strain for strain measurement, and can be used in a temperature environment as high as 600°C.