SOI-based arrayed waveguide grating with extended dynamic range for fiber Bragg grating interrogator

• A monolithically integrated SOI-based AWG has been designed, fabricated, and tested. • The input waveguide is optimized by considering the grating equation of the AWG. • The interrogator has both high resolution (1 pm) and large dynamic range (28 nm). • The measured response is matching well with the design value. Because of its high demodulation precision, arrayed waveguide grating (AWG) demodulation has recently gained popularity. However, due to the limitations in AWG output characteristics, previously reported AWG-based interrogation systems cannot achieve high resolution and a wide dynamic range simultaneously. Herein, we designed and fabricated a monolithically integrated novel silicon-on-insulator (SOI)-based AWG as a critical component of the fiber Bragg grating interrogation system. The fabricated AWG’s input waveguide is modified by inserting a 1 × 2 multimode interference (MMI) coupler into it. The combination of an input waveguide and an MMI coupler adds another peak to the AWG translation spectrum, indicating that at least two output channels have a significant signal at any measured wavelength. Furthermore, the core size of the AWG is small (482 × 710 um 2 ), while the measurement resolutions and dynamic ranges are large. The optimized AWG with low crosstalk (−16.78 dB), a wide dynamic range (28 nm), and a high resolution (1 pm) has excellent performance potential and is a prospective component for fiber Bragg grating interrogation.