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

Tower Semiconductor probably has little upside left, trading at 43x the $500M net profit it projects once its foundry buildout is complete and running at 85% utilization. By contrast, TSMC trades at 24x 2026 earnings. x.com 

Tower Semiconductor looks set to be the leading silicon-photonics foundry as the path to CPO runs through NPO. First NPO deployments are planned for 2027, with $1.3B of contract value for 2027 alone and more after. A multi-year IQE epi-wafer deal protects it from the InP bottleneck, it is bringing laser-to-silicon bonding in-house, and a dual-track 300 mm plan in Japan aims to quadruple capacity without dilution. Its SiPho coherent modules for Marvell have passed multi-million units. x.com 

IQE still has plenty of upside as Tower Semiconductor's indium phosphide epitaxial wafer supplier for the NPO-to-CPO buildout. Tower said its multi-year epi wafer agreement with IQE leaves it extremely well positioned against the InP bottleneck. Tower's first NPO deployments come in 2027, with $1.3B of contract value for that year and higher numbers expected after, and it plans to quadruple Japanese silicon photonics capacity, with full readiness in Q4 2027. x.com  x.com  x.com 

GlobalFoundries' margins should rise relative to Tower Semiconductor's, if reports on each company's 8-inch to 12-inch transition and capacity ramp are correct, even though both now have similar net margins. GlobalFoundries also trades at a much cheaper multiple than Tower. x.com 

Tower Semiconductor is a silicon photonics foundry behind the AI optical stack, and the market will price it for where its revenue mix is going. Its silicon photonics revenue doubled in 2025 on hyperscaler demand, more than 70% of capacity is booked through 2028, and it is partnered with Nvidia on next-gen optical modules. As @joedab12 noted, it is not a pure play yet: silicon photonics is still a minority of revenue, but the fastest-growing piece. x.com  x.com 

GlobalFoundries' new silicon germanium capacity deal with Marvell doesn't fix its position, because its SiGe is mediocre next to Tower's, though the gap is smaller than in silicon photonics. Semtech, and likely Macom, use Tower. x.com  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 

Tower Semiconductor's 2028 guidance makes its shares attractively valued around $180 despite competition from Silith, GlobalFoundries, STMicroelectronics and others. The stock previously felt too rich to add to. x.com  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