Coherent reported a significant breakthrough in improving the bandwidth of its vertical-cavity surface-emitting laser (VCSEL), paving the way for use in next-generation optical interconnects that will operate at 200 Gbps per lane and thereby enabling optical transceivers with 1.6 Tbps capacity.
This improvement comes in the form of lithographic-aperture VCSELs, marking a significant departure from the oxide-aperture VCSELs that are the state-of-the-art VCSELs used in AI networks today.
Oxide-aperture VCSELs are currently powering optical transceivers operating at 100G per lane data rates, including 800G (8x100G) multimode optical transceivers, but have reached their bandwidth limit of approximately 27 GHz.
The new lithographic-aperture VCSELs feature exceedingly small apertures with high reproducibility and reliability. With this innovative design, it is feasible to achieve a device bandwidth of approximately 45 GHz, which, when combined with recent advances in digital signal processing technology, can pave the way to 1.6T (8x200G) multimode optical transceivers.
Multimode transceivers and links are ideally suited for short-reach connectivity in data centers, spanning artificial intelligence (AI), high-performance computing (HPC), and networking applications.
A technical paper describing this leap in performance was presented by Dr. Stefano Tirelli, Senior Manager, VCSEL Technology, at OFC 2024.
“As a leading supplier of VCSELs for multimode 800G optical transceivers, we are pleased to extend our technological leadership on our roadmap toward next-generation 200G VCSELs,” said Chair and CEO Dr. Vincent D. (“Chuck”) Mattera, Jr. “The development of a reliable, lithographic-aperture VCSEL is a step in the right direction. While we have more work to do, we are very pleased with the progress we have made so far.”
