Celero Raises $275m to Bring Coherent Optics Inside AI Data Centres
Celero, a two-year-old chip startup, has raised $275m at a valuation above $3bn to push AI data down fibre. It has validated a 2nm chip but has not started production or named customers. Alphabet's CapitalG co-led the round, though Google is also a major Marvell customer.
September 10, 2026 – 1:02 pm
Credit: Kirill Sh on Unsplash
Celero Communications, a two-year-old chip startup, has raised $275m in a Series C round that values it at more than $3bn. It makes the processors that push data down fibre optic cables between AI chips, racks, and whole data centres. Atreides Management, Valor Equity Partners, and CapitalG, Alphabet’s growth fund, co-led the round.
Dina Bass of Bloomberg reported the round on 8 September, ahead of the company’s own announcement the same day. Existing investors Sutter Hill Ventures and Maverick Silicon also took part. Celero has now raised $415m in total. Gavin Baker, managing partner and chief investment officer at Atreides, joins its board.
All three lead investors were already on the cap table. CapitalG led Celero’s $100m Series B last November. That took its funding to $140m at the time, according to the company’s earlier announcement. Valor, Atreides, Sutter Hill, and Maverick Silicon took part in that round too. The November announcement gave no valuation, so the size of the step up is not public.
The company is based in Irvine, California, with design centres in Canada and Argentina. Its founders are Nariman Yousefi, the CEO, and Oscar Agazzi. The pair previously worked as executives at Marvell, and Yousefi spent 17 years at Broadcom, where he ran its networking unit.
What Celero Makes
Celero builds coherent digital signal processors (DSPs). These chips encode data onto light using the phase and polarisation of the signal as well as its brightness. That lets more data travel further down the same strand of fibre. Networks have long used coherent optics for links between cities. Inside data centres, a simpler and cheaper method called PAM4 has done most of the work.
Celero argues that PAM4 is running out of room as AI clusters grow. Its pitch is that coherent optics should now run at every scale, from racks inside one building to links between neighbouring data centres.
“The transition to coherent technology is absolutely required to enable all this future scaling for AI,” Yousefi told Bloomberg.
The company says it has validated what it calls the industry’s first coherent DSP made on a 2-nanometre process. It uses TSMC’s 2nm technology, the most advanced commercially available. Celero says the chip sets up a roadmap from 1.6 terabit connections to 3.2 terabit ones.
Not Shipping Yet
Celero says the new money will go towards its product roadmap, research and development, and production readiness. The validation is a milestone, not a product. Yousefi told Bloomberg that Celero still has to finalise the design and start production, and aims to make that move next year. The company has not named any customers. It is targeting the biggest cloud providers.
It will also have to sell into a crowded market. Celero will compete with Marvell, Broadcom, and Cisco, Bloomberg reported. At the same time, its chips must plug into equipment made by others. Marvell owns Inphi, one of the companies in the founders’ own history. Cisco bought coherent optics specialist Acacia in 2021.
The Alphabet link adds a twist. Last month, Marvell gave Google a warrant to buy up to $12.2bn of its shares as part of a custom chip deal.