High‐sensitive temperature sensor based on ethanol‐filled elliptical‐core side‐hole fiber Sagnac interferometer

Abstract

The birefringence properties of two types of side-hole fibers have been numerically studied, based on which a Sagnac fiber interferometer employing ethanol-filled side-hole fibers is proposed and experimentally demonstrated for high-sensitive temperature measurement. Thanks to highly temperature-sensitive refractive index of ethanol infiltrated in the air holes of side-hole fibers, high-sensitive temperature measurement could be realized by monitoring fiber-birefringence-induced resonance wavelength shift of the fiber Sagnac interferometer in response to environmental temperature variation. Experimental results show that within a temperature range of 26 C to 54 C, there exists some critical temperature point around 40 C, on both sides of which the resonance dips exhibit inverse temperature-dependent shift behaviors. A temperature sensitivity of 1.10 nm/ C is experimentally achieved for our proposed side-hole fiber Sagnac interferometer.

Highly sensitive temperature sensor based on multimode‐interference fiber structure with gel cladding

“…Additionally, the optical fiber sensors have the advantage of being able to measure and detect a variety of physical and chemical quantities using an optical fiber as a common device. To date, the fiber sensors based on various principles have been studied, such as multimode interference (MMI) devices, fiber Bragg gratings, long‐period gratings, Sagnac interferometers, and Brillouin scattering 1‐5 . Among these sensors, MMI‐based fiber sensors are unique in terms of their simple forms and versatility; they have been used to detect various characteristics, such as displacement, temperature, vibration, refractive index, and strain by measuring the change in the peak wavelengths or the transmission intensity 1,6‐9 .…”