High-Speed VCSELs for OOK and Multilevel PAM Modulation

Paper in proceeding, 2017

The short-reach optical interconnects used in datacenters and high-performance computing systems are dominated by vertical-cavity surface-emitting laser (VCSEL) and multimode fiber (MMF) links1. The VCSEL-MMF technology is the most cost and power efficient and offers the smallest footprint. VCSELs for 25-28 Gbit/s OOK lanes are in production2 while 25-28 Gbaud PAM-4 with forward-error-correction (FEC) is considered for next generation 50-56 Gbit/s lanes3. For this transition, as well as future developments towards even higher speed, the VCSEL dynamics and high-speed properties are of utmost importance. Improved dynamics may enable 50-56 Gbit/s PAM-4 without FEC and even 50-56 Gbit/s OOK, which would reduce complexity, power consumption, and latency.