A novel positioning and temperature measurement method based on optical domain demodulation in the BOTDR system

Abstract A Brillouin optical time-domain reflectometer(BOTDR) system based on optical domain demodulation is proposed. Based on the traditional microwave electro-optic modulation BOTDR system, a dual-pass unbalanced Mach–Zehnder interferometer is added to demodulate the optical signal before the photoelectric conversion, which realizes the optical domain demodulation and reduces the frequency of the signal The positioning and temperature sensing experiments are carried out. The positioning error is 3.7 m at a distance of 8170 m, and the minimum error of temperature measurement is 0.08 °C in the range of 25 °C–55 °C.