Multiwavelength Brillouin–Erbium Fiber Laser Temperature Sensor With Tunable and High Sensitivity

A multiwavelength Brillouin-erbium fiber laser (MBEFL) temperature sensor with high and tunable sensitivity has been developed and experimentally demonstrated in this paper. Owing to rigid Brillouin frequency shift spacing of MBEFLs, MBEFLs are very suitable for temperature sensing and can be used to realize high and tunable sensing sensitivity. By monitoring the center frequency shift of the beat signal spectrum of the two same-order Brillouin Stokes waves coming from the sensing MBEFL and the reference one, the high and tunable sensitivity has been realized. The proposed tunable temperature sensor realizes a finer tuning step. It shows a high stability and provides a sensing sensitivity of 13.08 MHz/°C and a tuning step of 1.09 MHz/°C. At 12th-order sensitivity, the temperature error is about 0.23 °C (±0.115 °C), and the temperature resolution is about 0.765 °C.