Advances in waveguide to waveguide couplers for 3D integrated photonic packaging

Area of Science:

• Photonics and Optical Engineering
• Materials Science for Optoelectronics

Background:

• Efficient optical coupling between waveguides is crucial for integrated photonic circuits.
• Novel methods for light transmission through various substrates are needed for advanced optical systems.

Purpose of the Study:

• To provide a comprehensive overview and comparison of optical waveguide-to-waveguide coupling devices.
• To discuss technologies for efficient light transmission through different substrates.
• To evaluate potential improvements in energy efficiency, performance, and cost for various applications.

Main Methods:

• Comparative analysis of coupling devices: inter-chip edge couplers, grating couplers, free form couplers, evanescent couplers, cantilever couplers, and optical wirebonds.
• Review of light transmission technologies: guided mode and free form photonic vias.
• Discussion of substrate materials: silicon, glass, and organics.

Main Results:

• Comparison of various coupling techniques highlights their strengths and weaknesses for different applications.
• Photonic via technologies offer efficient light transmission across diverse substrate materials.
• The integration of these technologies shows potential for significant gains in energy efficiency, performance, and cost.

Conclusions:

• The selection of appropriate waveguide coupling and light transmission technologies is critical for optimizing photonic integrated circuits.
• These advancements are poised to enable next-generation optical systems in areas such as co-packaged optics, quantum photonics, and LiDAR.