Resolving accuracy-resolution trade-off in FBG via bidirectionally symmetric input AWG combined with the CoG...

Area of Science:

• Photonics and Optical Engineering
• Integrated Optics
• Semiconductor Device Fabrication

Background:

• Arrayed waveguide gratings (AWGs) are crucial for wavelength-selective optical signal processing.
• Silicon-on-insulator (SOI) platforms offer advantages for integrated photonic devices.
• Fiber Bragg Grating (FBG) sensors require high-performance interrogation systems for accurate measurements.

Purpose of the Study:

• To propose and characterize a novel bidirectional symmetric input AWG architecture.
• To investigate the impact of design parameters on AWG performance.
• To demonstrate a high-accuracy FBG interrogation system.

Main Methods:

• Fabrication of a bidirectional symmetric input AWG on an SOI platform using a double-etching process.
• Systematic comparison of different AWG designs, interrogation strategies, and algorithms.
• Experimental characterization of the 2x12-channel interrogation chip's performance metrics.

Main Results:

• Achieved insertion loss <6 dB, 3-dB bandwidth of 1.467 nm, and crosstalk < -22.9 dB.
• Demonstrated interrogation accuracy of 3.94 pm with a resolution of 2 pm.
• Exhibited excellent temperature stability, overcoming accuracy-resolution trade-offs.

Conclusions:

• The developed bidirectional symmetric input AWG provides a viable approach for high-performance FBG interrogation.
• The study elucidates key relationships between design parameters and interrogation performance.
• This technology enables advanced FBG sensing applications requiring high accuracy and resolution.