Scaling VCSEL performance for 100terabits/s systems

We evaluate VCSEL interconnects for next-generation High Productivity Computers in which hundreds of terabits of bandwidth are envisioned. We present results for VCSEL based links operating PAM-4 signaling using a commercial 0.13μm CMOS technology. We perform a complete link analysis of the Bit Error Rate, Q factor, random and deterministic jitter by measuring waterfall curves versus margins in time and amplitude. We demonstrate that VCSEL based PAM-4 can match or even improve performance over binary signaling under conditions of bandwidth limited 100meter multi-mode optical link at 5Gbps. We present the first sensitivity measurements for optical PAM-4 and compare it with binary signaling. An empirical relationship for VCSEL scaling versus bit rate and aperture is presented in order to explore reliability of VCSEL-based links. Reliability is found to degrade with aperture with a fourth order power law dependence.

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