Demodulation of the FBG temperature sensor with the tunable twin‐core fiber

A novel linear edge filter based on a piece of tunable twin‐core fiber is proposed in this article.The transmission spectrum of the twin‐core fiber can be adjusted by pulling and twisting the twin‐core fiber to match the central wavelength of the Fiber Bragg Grating (FBG) used for the temperature sensor. The feasibility of the method is analyzed and demonstrated experimentally. This demodulation filter, which is based on the all‐fiber component, can be designed and adjusted according to the measurement sensitivity and range of FBG temperature sensor, so its characteristics of compact scheme and low cost would make this method more applicable.