A novel algorithm based on DFB tunable laser array for demodulation of FBG sensors

Abstract

In this paper, a high effective demodulate algorithm based on tunable four-channel DFB (Distributed Feedback) laser array is proposed. In comparison with common algorithms which can work correctly when tunable laser have to be rapidly tuned through FBG’s (Fiber Bragg Grating) whole spectrum, the algorithm is unique in that accurate demodulation can be done by scanning only 0.4 nm bandwidth of FBG’s reflected spectrum and the scanned spectrum can be any part of the whole FBG spectrum including those regions with relatively low power. Therefore, the laser tuning time and response time of demodulation system is much more reduced which is important for most applications that need dynamic, real-time measurements. Wavelength-division multiplexing for FBG sensing network will be supported by the demodulating system and algorithm. Based on strain experiments of the FBG sensing system, excellent demodulation accuracy were demonstrated by the proposed algorithm.