Coherent's 6-inch substrate access, yields and margin concerns look mostly like timing issues in the optical buildout. Coherent is now one of the preferred ways to gain exposure and should participate meaningfully, despite those constraints. x.comÂ
Gaetano
Thematic Investor, Photonics & Physical AI Research
Scarce 6-inch substrates could limit Coherent's margin upside for several quarters. If margins fail to expand meaningfully, limited deliveries are expected to be a primary reason: AXT and Sumitomo's ramp is weighted toward H2 2027 onward. Current wafers are difficult to process, with unclear yield gains over Coherent's 3-inch line. This is one of the biggest legitimate near- to mid-term bear cases, though Coherent still participates meaningfully in the optical supercycle. x.comÂ
Tighter Lumentum laser allocations would strengthen Coherent's pricing power if Marvell's rumored acquisition leads it to prioritize Nvidia and its own modules. Other buyers would face tighter supply, and hyperscalers would push harder to second-source lasers from Coherent. x.comÂ
AI bandwidth demand still favors Coherent and Lumentum, but tight customer financing can delay orders and lasting valuations need durable profits. A model provider losing share need not reduce total bandwidth use. Coherent could beat and raise guidance; Lumentum may only meet estimates this quarter, improving next quarter. If margins partly reflect scarce indium phosphide, added supply will test whether upgrades, volume and cost gains sustain earnings. These earnings calls remain forecasts. … Show more
Applied Optoelectronics has a better chance than Coherent of delivering a 300-400 mW laser with tolerable RIN and linewidth. Its transceiver capacity ramp is also larger and is not gated by Sumitomo's 6-inch InP wafers. Long AAOI against short COHR is an unnecessarily dangerous pair trade idea. x.comÂ
Coherent is getting stronger in the co-packaged optics era, with people on the ground describing its six-inch InP capacity, yields and ramp as really strong. Nvidia has invested $2B directly in the company, which joined the S&P 500 in March. x.comÂ
Coherent should benefit as the shift from copper to light inside AI data centers accelerates, with co-packaged optics now in production and near-packaged optics pulling revenue forward. Nvidia's Spectrum-X Photonics switch is in full production, and TrendForce says CPO has entered mass production. Coherent CEO Jim Anderson says CPO and NPO engagement jumped in the past three to six months, nearly every large customer has a project, and its content per socket is similar in either design. x.comÂ
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.comÂ
Indium phosphide laser capacity, not demand, now caps how fast 1.6T optics ship, and Coherent owns its laser fabs and grows its own substrate. That makes the InP squeeze Goldman flags through 2027 work in its favor. Record Q4 revenue of $2.05 billion rose 34% as six-inch InP wafers ramped, with 40.2% non-GAAP gross margin and 42%+ guided, at a 0.92 PEG. The risk: with about $3.55 billion of debt and cash burn, it can't absorb a 1.6T ramp slip; six-inch yield at volume is the test. x.comÂ
Coherent is a tactical buy because growth and margins should accelerate once its 6-inch production ramps, yield challenges notwithstanding. The quarter disappointed on a slower 2x InP ramp and slow margin progress toward 42%, with Coherent still reliant on Lumentum's lasers. Over the next 4-8 quarters it can catch up in simpler CW lasers, with OCS and CPO the real upside. Lumentum, growing about 90% versus Coherent's 20%, remains the preferred concentrated long-term AI-optics bet. x.comÂ
VCSEL scale-up optics may spread revenue across more suppliers because they lack the fundamental bottlenecks of InP lasers. Coherent looks well positioned, but the VCSEL opportunity may still be shared more widely; Lumentum is also betting on VCSELs for scale-up. x.comÂ
Coherent now has credible exposure to almost every optical architecture hyperscalers are exploring, and its Nvidia deal materially de-risks that roadmap. Nvidia's nonexclusive pact adds a multibillion-dollar purchase commitment, a $2B equity investment and access to five CPO product families. First CPO/NPO revenue targeted for H2 2026 matches Nvidia's timing. Data center and communications are already 72% of revenue. Qualification, standards, concentration and margins remain unsettled. x.comÂ