A Proposal of Temperature Sensing Using a Thin-Film Bandpass Filter and Dual-Wavelength Push–Pull Reflectometry

A new temperature sensing system, which utilizes a thin-film bandpass filter deposited on an optical fiber end face and dual-wavelength push-pull reflectometry, is proposed. The system has the following advantages over the fiber Bragg grating sensor: it can observe the temperature in a localized small area and it gets rid of microcrack growth caused by stripping of cover coating from a fiber. The feasibility of the system has been verified by simulation.