A chip-scale coherent microcomb enables high-capacity and lightweight optical transmission.
The demand for high-throughput, low-latency data aggregation at network edges is growing rapidly. However, existing integrated wavelength-division multiplexing (WDM) parallel light sources often suffer from limited coherence, low optical carrier-to-noise ratio (OCNR), insufficient output power, or large footprint, hindering the deployment of efficient and lightweight optical interconnects at network edges.
To address this, researchers from Huazhong University of Science and Technology and Peking University have developed an integrated self-injection-locked Kerr microcomb source [
1].
The device combines a semiconductor laser with a directly coupled high-quality-factor silicon nitride microring resonator, generating 16 carriers within the C-band, each with power above –10 dBm and intrinsic linewidth below 600 Hz. This enables a single-channel net data rate of 1 Tbps/λ/core in a self-homodyne system. Furthermore, by combining 16-channel WDM with space-division multiplexing (SDM) over a 24-core fiber, an aggregate net rate of 200.97 Tbps is achieved using 70 Gbaud DP-16QAM signals. The team also created a chip-scale parallel carrier generator by integrating on-chip semiconductor optical amplifiers and silicon photonic waveshapers, resulting in a fully integrated transmitter module that reduces the system footprint by two orders of magnitude while maintaining a 5 Tbps transmission capacity.
This work not only highlights the significant potential of microcavity optical frequency combs in high-speed coherent communications, but also provides a practical, ultra-compact solution for high-capacity edge optical interconnects, paving the way toward lightweight and energy-efficient data aggregation for distributed computing and modular data centers.
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