Efficient, tunable flip-chip-integrated III-V/Si hybrid external-cavity laser array.

Area of Science:

• Photonics
• Materials Science
• Electrical Engineering

Background:

• Hybrid silicon lasers are crucial for advanced photonic integrated circuits.
• Existing integration methods face challenges in scalability and performance.
• Tunable laser sources are essential for diverse optical applications.

Purpose of the Study:

• To demonstrate a novel surface-normal coupled tunable hybrid silicon laser array.
• To achieve high performance and scalability using advanced integration techniques.
• To provide a promising solution for high-density laser sources in future photonic systems.

Main Methods:

• Passively-aligned, high-accuracy flip chip bonding of a III-V reflective semiconductor optical amplifier (RSOA) array to a CMOS SOI chip.
• Integration of total internal reflection mirrors, grating couplers, and silicon ring reflectors.
• Optimization of metal/dielectric stacks to enhance laser performance.

Main Results:

• Demonstration of the first 2x6 surface-normal coupled tunable hybrid silicon laser array.
• Achieved waveguide-coupled wall plug efficiency (wcWPE) of 2% and 3 mW output power for all 12 lasers.
• Further improved performance to 10 mW output power and 5% wcWPE through stack optimization.

Conclusions:

• The developed integration approach is non-invasive and a one-step back end of the line (BEOL) process.
• This technology offers a promising solution for high-density laser sources in large-scale photonic integrated circuits.
• The demonstrated hybrid silicon laser array paves the way for next-generation optical systems.