Researchers at Fudan University and Zhangjiang National Laboratory have successfully developed a novel germanium photodetector on a 300-mm CMOS silicon photonics platform. This breakthrough innovation is designed to tackle increasingly demanding optical interconnect requirements for modern artificial intelligence infrastructure. You can explore related optics articles to learn more about similar foundational hardware advancements.
The newly engineered device achieves an impressive 110 GHz 3-dB bandwidth alongside a remarkable 95.3% peak quantum efficiency. This configuration yields an outstanding bandwidth-efficiency product of 104.8 GHz to power future high-speed optical links.
Engineering Breakthroughs in Photonic Design
Overcoming Traditional Trade-Offs
Traditional photonic designs constantly struggle to balance speed, sensitivity, and leakage currents. This newly announced detector effectively overcomes those historical compromises by maintaining a high responsivity of 1.01 A/W at 1310 nm while keeping dark currents exceptionally low below 10 nA.
Advanced Structural Configurations
At the core of the innovation is a semi-embedded germanium absorbing region that strengthens electric fields and shortens carrier transit times. Additional structural improvements include a triple-gradient doping profile and octagonal contact pads that actively minimize various forms of parasitic capacitance.
Scalable Performance for Future AI Networks
Rigorous Wafer-Level Testing
Extensive wafer-level testing demonstrated remarkably consistent performance across the board, with multiple dies successfully achieving the 110 GHz bandwidth milestone at a -3 V bias. Large-signal tests further confirmed clearly open eye diagrams at 320 Gbit/s with PAM-4 and 413 Gbit/s with PAM-6 modulation formats.
Thermal Stability and Deployment
Furthermore, the device retained completely stable thermal and operational performance up to 85 degrees Celsius. This robust reliability makes it an exceptionally scalable solution for powering single-lane 400-Gbps AI optical links moving forward.
Here is the source article for this story: Germanium photodetector hits 110 GHz bandwidth for 400-Gbps AI optical links
