LFW: What is Celestial AI doing tech-wise that differentiates you?

Lazovsky: Unlike other photonic technologies such as co-packaged optics (CPO), our Photonic Fabric can deliver data at any point on the silicon to the point of compute. And it isn’t limited to the edge of the silicon, so this shatters the package ‘beachfront problem.’ Photonic fabric offers >1.5 Tbit/s/mm2 package bandwidth, which is 25X greater than CPO. Because data is delivered directly to the point of compute and not at the edge, the latency is also 10X lower (at nanosecond latencies).

Photonic Fabric combines very high reach (100+ meters), extremely high bandwidth, and incredibly low latency because re-timers aren’t necessary. Low latency means Photonic Fabric can connect and disaggregate more servers than is possible with electrical interconnects. It also means even latency-sensitive applications can use remote memory, which wouldn’t be possible with electrical interconnects.

It’s also protocol-adaptive, supports industry standard protocols, and is compatible with interfaces like PCIe, UCIe, and other proprietary interconnects. And it can be integrated with high thermal design power (TDP) application-specific integrated circuits (ASICs) because the technology used isn’t as temperature-sensitive as CPO.

With CPO, the electro-optical(e-o)/ optical/electrical (o-e) conversions happen on a separate chiplet placed along the edge of the ASIC. Why? CPO uses ring modulators, which are very temperature-sensitive and can’t be placed beneath high-TDP ASICs. This limits the number of optical links you can have in a package to the linear perimeter—a.k.a. the ‘beachfront problem’ that limits the overall package bandwidth CPO can offer.

https://www.laserfocusworld.com/optics/article/14296728/qa-with-celestial-ais-dave-lazovsky