Addressing fiber Bragg grating sensors with wavelength-swept pulse fiber laser and analog electrical switch

摘要

A pulse train with a wavelength dependent time sequence is generated in a fiber laser configuration, which contains a cascaded wavelength-division-multiplexing (WDM) fiber Bragg grating (FBG) array and a tunable F-P filter. By distributing pulses to corresponding channels with a 1 x N analog electrical switch, a novel FBG sensors interrogation technique with advantages of high signal-to-noise ratio (SNR) and high interrogation speed is experimentally demonstrated. Then, a FBG sensing system based on this interrogation technique and the mature unbalanced scanning Michelson interferometer (USMI) demodulation technique is realized. The system has shown a sensitivity of 1.610 deg/(mu)(epsilon), for the 1555 nm FBG, which agrees well with the theoretical value of 1.674 deg/(mu)(epsilon).