Study of AWG optoelectronic hybrid integrated chip for FBG interrogation

Abstract:

Fiber Bragg Grating (FBG) sensing technology converts external environmental changes into FBG center wavelength drift. Then it uses an interrogation system to demodulate the offset of FBG center wavelength to measure external physical quantities. The demodulation effect on FBG center wavelength largely depends on the interrogation system's demodulation range, resolution, and accuracy. Therefore, to achieve continuous demodulation, high precision, and high resolution in the C-band, this paper designs simulates and prepares a 30-channel array waveguide grating (AWG) based on a silicon dioxide planar optical circuit for FBG interrogation and couples the prepared AWG with a photodetector array using hybrid integration technology. The test results indicate that the AWG has a good transmission spectrum, a 3-dB bandwidth of 2.15 nm, an insertion loss of approximately 3.6-4.2 dB, and crosstalk of less than -30 dB. The FBG interrogation system can achieve continuous demodulation in the dynamic range of 1521-1569 nm, and realize continuous demodulation in the C-band with a wavelength resolution of 1 pm and a demodulation accuracy of 5.8 pm. This demodulation method provides an optimization direction for researching fiber Bragg grating interrogation systems based on array waveguide gratings.