Raman frequency shift based light source at 1.66um for DTS application

In order to improving the sensing length of the Distributed Optical Fiber Temperature Testing System (DTS), a broadband pulsed source at 1.66um was proposed and demonstrated. A Raman frequency shifter, composed of a certain length single mode fiber (SMF) and a fiber band-pass filter was used as a key device to obtain the proposed light source. By changing the output power of the pump laser, the proposed broadband light source at 1.66um can be achieved with a bandwidth of ∼30nm, a pulse peak power of 18 W, pulse duration and repetition rate are, at all the same with the pump laser, 5ns∼1000ns and 1Hz∼100kHz respectively. In addition, relationships among output power of pump laser, fiber length in frequency shifter and output power at 1.66um were discussed. These characters facilitate a longer range DTS sensing with the spatial resolution maintaining.