High-sensitivity distributed random lasing sensor

We report temperature mapping of a single mode fiber by using a random lasing sensor driven by current pulses in a semiconductor optical amplifier. The backscattered light from the fiber provides random feedback for lasing with temperature sensitive wavelength in a similar way as fiber gratings do. The laser operates in mode locking regime with transform-limited pulses. We address the sensed region by varying the pulse repetition rate while the pulse width defines the resolution of the distributed measurement. We show that a ~100 m long-fiber can be easily mapped with temperature and spatial resolutions of 0.01°C and 50cm respectively.