High-temperature sensing using whispering gallery mode resonance in bent optical fibers

A new mechanism for high-temperature sensing with single-mode optical fibers is proposed. This sensing mechanism is based on whispering gallery mode (WGM) resonance in bent optical fibers. The interference fringes between the core mode and WGMs were induced by bending a cladding-thinned fiber and forming a loop in the fiber. The wavelength shift of the resonance peaks as a function of temperature is investigated. It is demonstrated that the single loop of bend ring in the fibers can be used as a transducer for high-temperature sensing without any internal structure.