Peking University develops unified silicon photonic coherent link for all distances

Researchers from Peking University, SiFotonics Technologies, and the Chinese Academy of Sciences have demonstrated a unified silicon photonic coherent platform designed for all-distance optical communications, according to a study published in Nature Communications nature.comNature Communicationsnature.comOpen source ↗. The architecture addresses the traditional division between short-reach links, which typically rely on intensity modulation due to hardware and energy constraints, and long-haul systems that require coherent transmission for high capacity.

Laser specifications and integrated transceiver

The platform utilizes a laser integrated with an ultralow-loss silicon nitride external cavity. This configuration achieves a direct optical output power of 70 mW, a sub-kilohertz spectral linewidth, and a wall-plug efficiency of 13.7%. Paired with silicon photonic transceivers, the system provides high spectral efficiency while mitigating the hardware complexity that previously restricted coherent optical architectures to long-distance infrastructures.

Short-reach throughput and long-haul transmission

During experimental evaluations, the platform supported unamplified short-distance data transmission across 256 wavelength channels, reaching an aggregate data rate of 81.92 Tb/s. For long-distance communications, the coherent platform maintained transmission over distances exceeding 4,400 km. Furthermore, the system demonstrated wavelength switching and the re-establishment of data transmission on timescales of tens of microseconds, enabling dynamic wavelength-routed optical connectivity.