Lightmatter raises $400M Series D at a $4.4B valuation

Lightmatter/Passage

Lightmatter raised a $400 million Series D led by funds advised by T. Rowe Price, with Fidelity and GV participating, valuing the company at $4.4 billion and bringing total funding to $850 million. The capital readies Passage, its 3D-stacked photonic interconnect, for mass deployment in data centers.

• $400M Series D at $4.4B valuation quadruples previous valuation; $850M total funding demonstrates investor confidence in photonics for AI infrastructure.
• T. Rowe Price–advised funds led the round with Fidelity and Google Ventures (GV) participating.
• Capital accelerates Passage 3D photonic interconnect readiness for mass deployment in next-generation AI data centers, moving data between processors with light.