Highly Sensitive Twist Sensor Based on Temperature- and Strain-Independent Fiber Lyot Filter

A novel highly sensitive optical fiber twist sensor based on a Lyot filter is proposed and experimentally demonstrated in this paper. The evolution of the transmission spectra of the Lyot filter with respect to twist, temperature, and strain are investigated, respectively. The amplitude of the resonance dip changes as a sine-like function with the twist angle varying, which agrees well with the theoretical analysis. Based on analyzing the amplitude response of the resonance dip, the sensitivities of the sensor with respect to twist, temperature, and strain are found to be -15.586 dB/rad, 0.003 dB/°C, and -0.001 dB/με, indicating the viability of implementing a temperature- and strain-independent twist sensor based on a Lyot filter.