Design and fabrication of AWG with large bandwidth applied in FBG interrogation system

Fiber Bragg Grating or FBG sensors are widely adopted in fields of structural health and temperature monitoring. The increasing demand for compact, high-performance FBG interrogators is highly desired. We have designed and fabricated high-performance arrayed waveguide gratings or AWGs using SOI technology with different parameters in FBG interrogator systems applications. Key parameters that affect FBG interrogating performance during AWG design are theoretically investigated and experimentally demonstrated. Using our proposed and optimized parameters, our fabricated AWGs have up to 2.88 dB of bandwidth, with low crosstalk and low on-chip loss. With custom supporting circuit, our proposed optimized AWG can keep the comparable interrogation accuracy and resolution performance to the previous best reported AWG based FBGI system while having four-time larger measuring dynamic range of 2 nm. This paper also provides guidance for optimizing the AWG-based FBG interrogation system during the AWG designing phase.