Optical Waveguide-Pair Design for CMOS-Compatible Hybrid III-V-on-Silicon Quantum Dot Lasers

Area of Science:

• Silicon Photonics
• Integrated Optics
• Semiconductor Lasers

Background:

• Compact, energy-efficient lasers at 1.3 µm are crucial for data communications and optical interconnects.
• Hybrid III-V-on-silicon lasers offer potential but face challenges in III-V/Si optical coupling, especially with standard 220-nm silicon waveguides.

Purpose of the Study:

• To numerically study distributed Bragg reflector (DBR) hybrid III-V-on-silicon lasers.
• To analyze design trade-offs and optimization strategies for 220-nm-thick silicon waveguides.
• To propose a novel epitaxial design for effective III-V/Si coupling and mode transfer.

Main Methods:

• Numerical simulations based on supermode theory.
• Analysis of mode profiles dependence on silicon waveguide dimensions and III-V stack geometry/composition.
• Investigation of epitaxial design for optimized optical confinement and mode transfer.

Main Results:

• Identified dependencies between mode profiles, silicon waveguide dimensions, and III-V stack characteristics.
• Proposed a novel epitaxial design enabling effective III-V/Si coupling.
• Demonstrated strong optical mode confinement in the III-V gain section and efficient transfer to the silicon waveguide.

Conclusions:

• The proposed novel epitaxial design facilitates effective III-V/Si coupling using 220-nm-thick silicon waveguides.
• The design ensures efficient optical mode transfer between gain and passive sections.
• The developed hybrid laser design exhibits robustness against fabrication variations, crucial for CMOS compatibility.