Celestial AI lands $100M for ‘disruptive’ optical interconnects

Silicon Valley startup describes approach as a ‘foundational building block for accelerated computing’.

Celestial AI, a Santa Clara, California, firm working on what it calls “Photonic Fabric” optical interconnects, has raised $100 million in its series B venture funding round.

Founded by CEO David Lazovsky and COO Preet Virk in 2020, and previously known as “Inorganic Intelligence”, the company says that its technology is aimed at deployments in “disaggregated, exascale compute and memory clusters”.

“The bandwidth delivered by the Photonic Fabric is 25x greater and delivers more than 10x lower latency and power consumption than any optical interconnect alternative, such as co-packaged optics (CPO),” it claims.

The latest funding round complements a $56 million effort closed in February 2022, when Celestial AI said that the industry was “ripe for commercial implementation of machine learning and high-performance computing solutions based on integrated silicon photonics for data movement”.

‘Accelerated computing’
Lazovsky said in a press release announcing the series B completion: “A rapid transition will take place in the coming years as global data center infrastructure transitions from general purpose to accelerated computing systems.

“This next wave of data center infrastructure is being architected to deliver tremendous advancements in AI workload efficiencies, resulting from disaggregation of memory and compute resources which is enabled by optical interconnectivity. Our technology solutions are lighting the way to the future of accelerated computing.”

The approach is claimed to deliver optical connectivity performance levels that are “ten years more advanced” than existing offerings – with Celestial AI explaining that it can offer direct and fully optical compute-to-memory links.

“This allows the processor to address optically connected high-bandwidth memories (O-HBMs) in addition to the conventional electrical HBMs along the die edge.”

According to the company, this means that Photonic Fabric increases the addressable memory capacity of individual processors, including GPUs and other AI processors.

Celestial AI says that the technology is available to license, as part of its plan to build a robust ecosystem among logic and memory suppliers, as well as hyperscalers and high-volume commercial supply chain partners.

The company also uses Photonic Fabric as a key technology for its own “Orion AI accelerator” product, while its multi-chip “Orion Hercules-GT” server is being designed to provide independent scalability of compute and memory with O-HBM.

Celestial AI indicates that the technology revolves around its “Optical Multi-Chip Interconnect Bridge” (OMIB), which is said to allow connectivity from any point on one die to any point on another die.

“This can help silicon designers move data photonically inside the package at high bandwidth, and reduce interconnect congestion, power, and area,” it states.

‘Disruptive moment’
Chase Koch, the founder and CEO of investor Koch Disruptive Technologies, described the optical connectivity technology developed by Celestial AI as “transformational”, adding that it would deliver step-change advancements in both the performance and energy efficiency of high-performance computing.

“We believe this could be a truly disruptive moment for advanced computing and we are excited to be a part of it!” he said in Celestial AI’s release. Other major supporters in the round included IAG Capital Partners and Temasek’s Xora Innovation fund, as well as Samsung Catalyst, Smart Global Holdings, Porsche Automobil Holding SE, The Engine Fund, imec.xpand, M Ventures, and Tyche Partners.

According to analysts at Yole Intelligence, the most active and visible firms in the CPO space include major players in the form of Intel, Nvidia, Marvell, Cisco, and Ayar Labs.

Ayar, which has developed optical “chiplets” as an alternative to traditional copper backplane and pluggable optical links, has itself raised more than $150 million in venture support, and said in May this year that it was using its most recent $25 million top-up to speed commercialization efforts.

According to their LinkedIn profiles, CEO Lazovsky previously spent six months as a venture partner at Khosla Ventures prior to co-founding Celestial AI, and was a director at POET Technologies, the Canadian developer of integrated photonic semiconductor wafers, for five years.

COO Virk was previously a senior manager at semiconductor firms MACOM, Freescale, and Mindspeed Technologies before it was acquired by MACOM.