Method For Reducing Crosstalk Interference In An Inline Fabry-Perot Based Fiber Bragg Grating Sensor Array Based On Layer Peeling Algorithm

Large-scale arrays based on fiber Bragg grating of great interests and widely potential application, are heading for the fiber optical sensing. Meanwhile, Time-Division-Multiplexing (TDM) is significant one of the most basic and efficient multiplexing technologies that large- scale array could adopt. However, with the TDM architecture alone, the level of multiplexing and sensitivity that can be achieved are limited by optical crosstalk which raise noise level.This dissertation presents a method for reducing crosstalk between sensors in an inline Fabry-Perot (F-P) sensors array utilizing layer peeling algorithm. Principles and key technologies of the method, as well as related theory are present. An algorithm is designed on the basis of optical heterodyne demodulation technology to determine impulse response matrix. In order to test and verify layer peeling algorithm, a TDM fiber optical sensing system composed of fiber Bragg gratings is developed. Experiments are carried out to get two TDM channels of signals. Simulating acoustic signal of different frequency and different amplitude are used in the experiments. It is innovatively designed that the light polarization modulator is replaced by a polarimeter. The experiment results show that layer peeling could effectively reduce crosstalk in the TDM fiber optical sensing system based on fiber Bragg gratings. Crosstalk from signal of 1kHz in frequency and 0.5rad in amplitude in the TDM system mentioned above could be reduced by 12dB. Moreover, crosstalk with frequency in the range from 630Hz to 2kHz could be reduced by layer peeling algorithm, and crosstalk with amplitude between 0.25rad and 1.6rad could drop as well, due to layer peeling algorithm.Research and work in this dissertation will have positive effects on reducing TDM crosstalk and promote the development of the large-scale fiber-optic sensing array.