Grating design for interlayer optical interconnection of in-plane waveguides.

Area of Science:

• Photonics and Optical Engineering
• Nanophotonics
• Computational Electromagnetics

Background:

• Optical interconnects are crucial for high-speed data transmission.
• Efficient coupling between gratings is essential for device performance.
• Existing numerical methods face challenges with complex multilayer gratings.

Purpose of the Study:

• To simulate and optimize interlayer grating-to-grating optical interconnect coupling efficiency.
• To introduce and validate the equivalent index slab (EIS) concept for enhanced RCWA.
• To address numerical sensitivity in analyzing multilayer grating structures.

Main Methods:

• Rigorous coupled-wave analysis (RCWA) was employed for simulation.
• The novel equivalent index slab (EIS) concept was developed.
• RCWA-EIS was applied to binary rectangular-groove gratings.
• Results were validated against the finite-difference time-domain (FDTD) method.

Main Results:

• The RCWA-EIS method effectively simulates and optimizes grating coupling efficiency.
• The EIS concept alleviates numerical sensitivity issues in RCWA.
• The method demonstrates applicability to arbitrary grating profiles and material properties.
• Excellent agreement was found between RCWA-EIS and FDTD simulations.

Conclusions:

• The RCWA-EIS approach offers a computationally efficient and robust method for optical interconnect design.
• This technique is suitable for complex multilayer structures with varying parameters.
• The proposed method facilitates optimal design based on specific system requirements.