From the B&C archives, 

Photonic Fabric Comparison

posted on Dec 27, 2023 10:13AM

Use the IP Check tool [?]

Hogan Junior posted in the Off Topic, inquiring about photonic fabrics which prompted me to respond after listening to Lightmatter’s whiz kid, Nick Harris:  https://m.youtube.com/watch?v=FPW2nnEqfMs

Lightmatter has a photonic fabric called "Passage". It is an oNOC (optical network on a Chip) as is Celestial’s accelerator.  

Lightmatter’s photonic fabric is a monster chip of 8X8 inches. Optical I/O takes place directly to and from any ASIC within the 64 square inch fabric by network addressable “stitched together” nanophotonic waveguides. A multi-mode fiber connects to the fabric delivering huge bandwidth.

A cluster of Celestial’s accelerators are connected by single-mode fiber. Optical I/O takes place to and from devices within an accelerator and to and from any other device on any accelerators within the fabric (cluster).     

Dylan Patel (semianalysis.com link at bottom) gives his analysis on Lightmatter and concludes with: "This could be vaporware, or it could be the future for high-end leading edge disaggregated server designs. Lightmatter has to woo other companies to build chips for this platform. These firms have to trust their expensive development with an unproven partner."

https://www.semianalysis.com/p/beyond-advanced-packaging-lightmatter