How Soitec Is Using Deposits and Fixed Prices to Control Scarce AI Optics Wafer Supply

AI data-center buildouts need high-speed optical links as well as accelerators and memory. That demand is giving Soitec, a supplier of Photonics-SOI substrates used in optical transceivers, an unusually strong way to manage scarce capacity: customers reserve wafer volumes years ahead, accept fixed prices and put down deposits. The reported addition of inventory disclosures is important because it makes reservations more useful as an allocation signal—not merely a queue for scarce supply. 140

What Soitec’s reservation agreements do

Soitec’s contracts are reported to combine three commercial tools:

• Multi-year capacity reservations secure a customer’s planned wafer volume ahead of production.
• Fixed prices reduce the customer’s exposure to price changes but also limit its ability to renegotiate if demand weakens.
• Deposits tied to committed volumes give customers a financial reason to reserve only supply they expect to use. Reports say deposits are returned when agreed purchasing volumes are met and forfeited when they are not. 40

This is a way to convert uncertain future demand into more bankable manufacturing commitments. Reuters reported that Soitec’s existing capacity covered the current year and the following year, so the practical value is principally in managing future incremental supply and supporting expansion decisions. More than 10 photonics-customer agreements were under discussion, with about 80% expected to be signed shortly after the late-August report. 1

Why customer inventory disclosure matters

A capacity reservation can be distorted when customers book extra volume as insurance during a shortage. Reported inventory disclosure requirements give Soitec more context: it can compare a customer’s requested allocation with the wafers it already holds and better distinguish expected consumption from precautionary stockpiling. 40

That does not eliminate forecasting risk, and the exact allocation criteria are not public. But the mechanism should reduce incentives to lock up capacity simply to crowd out rivals. It also gives the supplier more credible demand data when it decides how quickly to add capacity.

The source of seller power—and its limits

UBS has estimated that Soitec holds about 95% of the photonics-substrate market, a figure reported in coverage of the agreements rather than a company-verified market-share disclosure. If accurate, that concentration gives Soitec substantial leverage at a specialized upstream point in the silicon-photonics supply chain. 35

The contracts do not mean Soitec can create capacity instantly. They instead place more of the reservation and cancellation risk on buyers while giving the supplier better revenue visibility. For customers making AI-optics components, the trade-off is clear: secure supply early, but accept less purchasing flexibility.

Demand is accelerating faster than the capacity response

Photonics-SOI is becoming a material growth business for Soitec. The company reported revenue above $100 million for fiscal 2026, and its first-quarter fiscal 2027 update said Photonics-SOI sales doubled year over year, driven by high-speed optical transceivers for AI data centers. 239

The outlook subsequently strengthened. In its September 2 trading update, Soitec said it expected fiscal 2027 Photonics-SOI revenue to be 2.5 to 3 times the slightly-more-than-$100 million recorded in FY2026. 16

That trajectory supports the use of long-term reservations: the company is expanding into a market where demand signals are strong but investment and customer commitments need to be coordinated well ahead of shipment.

Singapore expands supply, but qualification still governs the ramp

Soitec’s capacity plan includes a transition to 300 mm production in Bernin and Singapore. In July, it said its Singapore 300 mm SOI fab had qualified for high-volume Photonics-SOI manufacturing with initial customers and that additional customer qualifications were under way. 339

The distinction matters. A fab becoming capable of volume production is not identical to instantly available supply for every buyer. Individual customers must qualify the material and processes for their products. The Singapore ramp therefore increases Soitec’s ability to serve demand, but it remains a staged expansion rather than an immediate end to scarcity.

CoWoS shows that AI bottlenecks move through the chain

The same economic pattern appears downstream in advanced packaging. CoWoS, a TSMC packaging technology used for AI accelerators, has remained tight despite aggressive expansion. A June report citing industry estimates put the CoWoS supply-demand gap at roughly 20% at the time, potentially narrowing to about 10% by the end of 2026; those are estimates, not TSMC guidance. 17

Capacity figures vary by source and by whether partner capacity is included. One recent estimate places TSMC’s CoWoS capacity at about 35,000 wafers per month at the end of 2024 and projects roughly 125,000–130,000 by the end of 2026—approximately a fourfold increase, not a near-ninefold increase. 19 Even substantial production additions can remain inadequate when demand rises at the same time.

The broader lesson for AI hardware buyers

AI infrastructure is not constrained by a single component. Specialized photonics substrates, optical-transceiver production, advanced packaging and other qualified manufacturing steps can each become a gating factor.

Soitec’s contracts show what supplier power looks like at one such bottleneck: reserve capacity early, pay to make the reservation credible and provide information that helps the supplier allocate constrained output. For buyers, the implication is operational rather than theoretical: access to critical AI-hardware inputs increasingly depends on supply commitments made well before final system demand is visible.