Dual-parameter optical fiber sensor based on intermodal interferometer with an inline embedded fiber Bragg grating

摘要

A dual-parameter optical fiber sensor is proposed and demonstrated. It is based on an intermodal interferometer (IMI) with an inline embedded fiber Bragg grating (FBG). The IMI is formed by cascading a taper structure and a spherical-shaped structure through a segment of a single-mode fiber. Due to the different wave-length shifts of the IMI and FBG to temperature and liquid level, simultaneous measurement can be achieved. Experimental results indicate a good linear relation between the wavelength shift and external parameters (temperature and liquid level). The sensitivities of 0.066 nm/°C and -0.133 nm/mm are achieved experimentally for temperature and liquid level, respectively. The interesting properties of the sensor include good operation linearity, compact size, and high sensitivity.