A multi-channel AWG-based FBG interrogation system using a 1 × 4 MEMS optical switch

Fiber Bragg grating (FBG) sensors have been widely used in various fields. In order to further multiplex FBG sensors, multi-channel interrogation systems have been widely studied. In this paper, a multi-channel AWG-based FBG interrogation system using a 1 × 4 MEMS optical switch is proposed. We simulate, design, and fabricate a 32-channel AWG based on silica planar lightwave circuit (PLC), and test the spectrum performance of the AWG. The test results show that the AWG has a good transmission spectrum with an average 3-dB bandwidth of 2.29 nm, an insertion loss of 2.52 dB to 3.95 dB, and a non-adjacent channel crosstalk of –23.06 dB. A temperature experiment is conducted on the multi-channel AWG-based FBG interrogation system. According to the experimental results, the multi-channel FBG AWG-based interrogation system achieves an accuracy within 20 pm, interrogation stability of $\pm 1.07$ pm, sensitivity of about 10 pm/°C, a correlation coefficient of about 0.9982 with a deviation within $\pm$ 0.002, excellent linearity, and the ability to interrogate 64 FBGs simultaneously.