Soitec's SOI wafers remain necessary no matter who builds optical engines if co-packaged optics standards take hold. Around 95% of these photonics wafers come from Soitec, so consolidation among module makers changes the buyer, not the need for wafers. Large buyers such as TSMC or Broadcom could pressure pricing and seek a second source, though none is apparent before 2030. That pricing risk is by far smaller than the module makers' architecture risk. x.com 

Soitec wins from Google's TPUv8i regardless of which foundry builds the chips, because it supplies the photonics-SOI wafers upstream. TPUv8i's silicon-photonics optical circuit switch adds a new layer of large photonic dies, and its signal loss forces transceivers to go coherent, using about 2-2.5x more silicon per port and roughly 3-4x the wafer starts. Risks include coherent modulators moving to indium phosphide or thin-film lithium niobate, and Marvell building its own photonics. x.com 

Soitec now looks overextended after a rapid run, and a pullback is likely. The AI photonics bottlenecks behind the thesis are real, but it is hard to judge what premium each name deserves, which makes the stock hard to value at these levels. x.com 

Soitec holds a monopoly on the Photonics SOI wafers the AI photonics trade runs through, yet trades at just 3.6x forward EV/revenue. Silicon photonics chips in AI data centers, from transceivers to Nvidia switches and Broadcom ASICs, are built on it via its proprietary Smart Cut process; GlobalWafers exits by 2027 and Shin-Etsu sells little. Optical interconnect grows from about $10 billion to over $70 billion by 2030, and top customer Tower Semiconductor targets 5x capacity by end-2026. x.com 

Co-packaged optics standards could make finished transceiver modules smaller and more interchangeable as chip designers build optical engines inside their packages. That is another reason to avoid Lumentum, Coherent and Applied Optoelectronics and prefer Soitec. Lumentum and Coherent now earn a lot from finished modules, leaving them exposed if the architecture changes. x.com 

Soitec's guidance shows AI optical demand turning into real revenue upstream, in the silicon-photonics substrate layer. It now expects $250M-$300M of Photonics-SOI revenue in FY2027, up from just over $100M, driven by AI data-center optical connectivity. Q2 Photonics-SOI revenue should triple and overall Q2 growth guidance rose to about 50% from over 30%. Planned multiyear deals with eight of about ten major customers suggest they see it as strategic supply. This isn't purely a CPO signal. x.com 

Soitec's chokepoint thesis is being validated as silicon photonics goes mainstream. UBS estimates it holds 95% of the substrate market for silicon photonics chips, and revenue usually flows through such a monopoly-like position. Soitec now expects 80% of more than 10 capacity reservation agreements within one to two weeks and calls $200M of photonics-SOI revenue absolutely a floor. TSMC sees silicon photonics topping 50% of the optical transceiver market in 2027. x.com  x.com 

Soitec's Q1 shows its photonics wafer monopoly turning into growth. It makes the Photonics-SOI substrate under nearly every silicon photonics chip, from TSMC's COUPE to Applied Optoelectronics and Coherent transceivers and Nvidia and Broadcom CPO switches, with 95%+ share. Photonics-SOI sales doubled to over half the €65M Edge & Cloud AI segment. Revenue of €113M rose 23% at constant currency versus 15% guided, Q2 guidance is 30%+ versus 4% expected, and its Singapore 300mm fab qualified early. … Show more

Soitec is now a bet on its future photonics ramp, since the next few quarters will be bad too. Buying today means buying that photonics story, with the weaker mobile segment carried along with it. x.com 

Soitec looks compelling again because the market misunderstands its book value, its underutilized fabs and the wafer area co-packaged optics will need. Depreciation on idle capacity is compressing earnings. @WalterA09213626, whose post is quoted, notes the share price fell from an all-time high of €200 to €116 over the past month. x.com