CadenceCONNECT Photonics
Presenter: Reza Baghdadi, Director of Verification & Bring-Up
Abstract: Massively Scalable Photonic I/O: Lightmatter’s Passage Platform for AI Interconnects
As AI workloads scale across thousands of accelerators, the system bottleneck has shifted from compute to interconnect. Scale-up fabrics now demand bandwidth, energy efficiency, and latency that copper cannot deliver: link reach collapses as signaling rates climb, and electrical I/O stays confined to a package shoreline that shrinks as logic consumes the die. We present a 3D co-packaged optics (3D-CPO) platform that places dense WDM optical interfaces directly beneath the compute die, converting a shoreline-limited bandwidth problem into an area-limited one. The platform is built on silicon microring modulators — compact, low-power, and the only modulator class compatible with 3D integration — with closed-loop thermal control that holds resonance across the full operating range of a compute package, paired with coupled-ring demultiplexers and high-speed photodiodes on the receive side.
The talk follows these devices through three platforms that trace the path from device demonstration to deployable infrastructure. Passage® EVK50 establishes the first 16-wavelength bidirectional link, proving that full-duplex WDM on microrings is viable over a single fiber. Passage EVK100 extends the architecture to an industry-first 1.6 Tbps on a single fiber, with receiver sensitivity measurements showing real operating margin rather than a marginal link. Passage M1000 moves from link to fabric as a wafer-scale active photonic interposer, integrating SerDes, drivers, and optics with no intervening electrical reach, stitching waveguides across reticle boundaries, and delivering compute-grade power through TSVs.
The talk concludes with what this progression enables for system architects once bandwidth no longer depends on distance, and the open problems in laser integration, packaging, and standardization, where Lightmatter is a founding member of the XPO MSA.
Date: October 14, 2026
Time: 2:15 PM PT
About CadenceCONNECT: The photonics industry didn’t reach maturity by accident. It took a decade of deliberate progress, collaboration, and vision. CadenceCONNECT Photonics 2026 brings together the people who made it happen and the innovators who will define what comes next.