Scale Across, Confirmed
A four-way cross-read of Arista, Coherent, Lumentum, and Nokia
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Scale across is the optical interconnect between AI data centers. When a cluster outgrows a single building, the workload distributes across multiple sites tens to hundreds of kilometers apart. The interconnect between those sites runs on coherent optics, not IMDD or copper. The hyperscalers describe the resulting distributed fabric as an AI factory. Ciena counts more than 300 new AI data centers operationalized globally in 2025, with the figure expected to nearly double by 2030.8
A year ago, scale across was a concept tucked into the back of OFC technical sessions. This past earnings season, four of the most-watched names in optical and networking spent real airtime on it. Look at how often it came up on each call. Arista said “scale across” more than 15 times on its Q1 call.1 Lumentum (LITE 0.00%↑) used it more than a dozen times,2 called it the “next leg of margin expansion”, and admitted that the supply-demand imbalance there is now wider than its already-tight EML imbalance. Coherent (COHR 0.00%↑) folded it into the communications segment that grew 60% year over year and called it the fastest-growing piece of the business.3 Even Nokia, whose call read more telecom than cloud, drew an analyst question framing scale across as its main optical opportunity.4 Infinera is starting to look like the deal that flipped Nokia’s optical fortunes.
I have written about scale across as the third tier of AI networking before in the article below. I will be going into more depth in a part 2 piece.
This piece walks through what was said in the print, what they have in common, and what the supply chain looks like underneath.
