Abstract:
The increasing bandwidth demands of data center and high-performance computing systems are motivating a shift toward co-packaged optics, where optical transceivers are integrated directly alongside compute or switch ASICs to reduce electrical channel losses. This talk presents a circuits-and-systems overview of VCSEL-based co-packaged optical transceivers developed at Intel Labs, focusing on architectural choices and design approaches that enable 50+ GBaud optical links over rack-scale optical reaches. Using two generations of co-packaged optical transceivers as examples, the talk describes the design of VCSEL drivers, receiver front ends and equalization, and clocking architectures that enable a 50-Gb/s NRZ link at sub-3-pJ/b efficiency and a 108-Gb/s PAM-4 direct-drive optical engine at sub-pJ/b. The talk emphasizes co-design with optical devices and packaging constraints, and circuit techniques to account for bandwidth and noise limitations of VCSELs and photodiodes.
Personal Bio:
Sashank Krishnamurthy was born in Chennai, India in 1993. He received the B.Tech degree in Electrical Engineering from the Indian Institute of Technology Madras, Chennai, in 2015, and the M.S. and Ph.D. degrees in Electrical Engineering from the University of California at Berkeley, in 2020. Since 2021, he has been a Research Scientist with Intel Labs, Hillsboro, where he works on ultra high-speed integrated electrical/optical transceivers. He has also been a Visiting Lecturer with the University of California at Berkeley. His current research interests include analog, mixed-signal, high-speed digital, RF, and millimeter-wave circuit techniques.