Precise control of the coupling coefficient through destructive interference in silicon waveguide Bragg gratings.

Area of Science:

• Photonics and Optical Engineering
• Materials Science
• Nanotechnology

Background:

• Waveguide Bragg gratings are crucial components in integrated photonics.
• Fabrication limitations, such as mask grid size, can introduce errors affecting grating performance.
• Precise control over grating strength is essential for advanced photonic integrated circuits.

Purpose of the Study:

• To introduce a novel method for fabricating waveguide Bragg gratings with tunable strength.
• To demonstrate the effectiveness of sidewall corrugation misalignment for grating control.
• To mitigate fabrication errors in silicon-on-insulator (SOI) photonic devices.

Main Methods:

• Design and fabrication of waveguide Bragg gratings on a silicon-on-insulator platform.
• Implementation of misaligned sidewall corrugations to tune grating strength.
• Utilizing the finite-difference time-domain (FDTD) method for simulation and analysis.

Main Results:

• Demonstrated tunable grating strength by varying the misalignment of sidewall corrugations.
• Achieved a wide range of grating coupling coefficients with precise control.
• Significantly reduced quantization errors associated with finite mask grid sizes.
• Experimental results showed excellent agreement with FDTD simulations.

Conclusions:

• Misaligned sidewall corrugations offer an effective method for tuning waveguide Bragg gratings.
• This technique enhances fabrication precision and performance for SOI photonic devices.
• The approach provides a robust solution for achieving desired grating characteristics in integrated optics.