Remote temperature sensing with a low-threshold-power erbium-doped fiber laser

A temperature sensor realized by a single-wavelength erbium-doped fiber laser is demonstrated in this work. The configuration of the laser cavity is linear, comprising a physical mirror at one end, and the other end is formed by a combination of a fiber Bragg grating and random distributed Rayleigh feedback of a 30 km single-mode fiber. As a result of erbium amplification, the laser has low threshold pump power at 10.6 mW. Additionally, the laser has good stability with power fluctuations of less than 0.37 dB over a 30 min duration. With this fiber laser, a temperature sensor with sensitivity of 10.6 pm/°C can be realized for a temperature range from 30°C–90°C. The sensitivity value is comparable with those obtained with Raman-based fiber lasers, albeit with the requirement of lower threshold pump power.