Frequency Comb-Injection Locked Coherent Optically-Switched Transceivers for Intra-Data Centre Networks

Data centres, comprising tens of thousands connected servers, are the underlying technology empowering everything we do online.

Driven by cloud computing and big data services, server-to-server traffic in data centres is increasing at an annual rate of 70%. This has motivated the development of 400G Ethernet, which is expected to scale to ≥1.6Tb/s in the future.

This increase has resulted in both architectural and interconnection challenges.The first challenge is the scaling of the data centre network, which is expected to reach hundreds of thousands of servers.

This trend has driven research in optical switching as an alternative to electronic switching for its fast switching in nanoseconds. The second challenge is the scaling of the data rate of the server-to-server interconnects.

This makes coherent transceivers attractive as they offer higher spectral efficiency than current intensity-modulation direct-detection schemes.Future intra-data centre interconnects therefore require revolutionary technologies to address both challenges.

But commercially available coherent transceivers, which are designed for long-haul, continuous data transmission, cannot meet the requirements for optically-switched data centre interconnects.

Technical challenges include fast wavelength tuning, low-latency optical carrier recovery and equalisation.In COINCOST, I propose to develop coherent optically switched transceivers by designing and optimising frequency comb and injection locking techniques that address these technical challenges.

These will be realised in photonic integrated circuits (PIC) in a cost- and power-efficient fashion and demonstrated in systems on the host’s unique platforms.COINCOST draws on interdisciplinary but complementary expertise from the host, industrial partners, and me, e.g., PIC, DSP, and clock-synchronised data centre networks.

COINCOST will open new opportunities for me to lead research and benefit the photonics and communication industry in Europe.