Single step etched two dimensional grating coupler based on the SOI platform.

Area of Science:

• Photonics and Optical Engineering
• Materials Science and Nanotechnology

Background:

• Two-dimensional grating couplers (2D GCs) are essential for efficiently coupling light into and out of photonic integrated circuits.
• Conventional 2D GC fabrication often involves multiple complex lithography and etching steps, increasing manufacturing cost and time.

Purpose of the Study:

• To design and demonstrate a simplified, single-step etched 2D GC on a silicon-on-insulator (SOI) platform.
• To achieve comparable optical performance to existing 2D GCs while significantly reducing fabrication complexity.

Main Methods:

• Utilized subwavelength cylinders for the 2D GC design on an SOI platform.
• Integrated the 2D GC fabrication into the same single lithography and etching process as the strip waveguide, accounting for the lag effect.

Main Results:

• Successfully designed and demonstrated a single-step etched 2D GC.
• Achieved a measured coupling loss of -6.0 dB, which is comparable to conventional shallowly etched 2D GCs.
• Demonstrated fabrication simplification without compromising optical performance.

Conclusions:

• The proposed single-step etched 2D GC offers a viable alternative for photonic integrated circuits.
• This fabrication approach simplifies manufacturing processes, making 2D GCs more accessible and cost-effective.