A 3.584 Tbps coherent receiver chip on InP-LiNbO₃ wafer-level integration platform

Area of Science:

• Photonics and Optical Engineering
• Materials Science
• Integrated Circuit Design

Background:

• Thin-film lithium niobate (LiNbO₃) is crucial for high-performance photonics, but chip-level integration limits scalability and cost-efficiency.
• Integrating direct-bandgap materials for ultrahigh-speed photodiodes and coherent receivers on LiNbO₃ remains a significant challenge.
• Existing platforms struggle to meet the demands of high-speed optical interconnects and mmWave/THz applications.

Purpose of the Study:

• To develop a scalable, wafer-level heterogeneous integration platform combining Indium Phosphide (InP) and LiNbO₃.
• To overcome fabrication challenges for integrating high-speed active components onto the LiNbO₃ platform.
• To enable ultrahigh-speed photodiodes and advanced optical coherent receivers for next-generation communication systems.

Main Methods:

• Developed a wafer-level heterogeneous integration process for InP and LiNbO₃.
• Fabricated ultrahigh-speed photodiodes using the integrated platform.
• Designed and demonstrated a multi-channel optical coherent receiver chip.

Main Results:

• Achieved ultrahigh-speed photodiodes with a 140 GHz bandwidth, capable of receiving 100-Gbaud PAM4 signals.
• Demonstrated a seven-channel coherent receiver with an aggregate capacity of 3.584 Tbit/s, featuring 60 GHz balanced detection bandwidth and >20 dB CMRR.
• Attained high data rates (up to 600 Gbit/s/λ) with advanced modulation formats and low energy consumption (as low as 9.6 fJ/bit).

Conclusions:

• The InP-LiNbO₃ wafer-level integration platform offers a scalable solution for high-performance photonic integrated circuits.
• This technology enables the realization of critical components for Pbps hyperscale data center interconnects.
• The platform paves the way for advancements in optical mmWave/THz sensing and communication systems.