More lasers per module and new 400G DSPs could keep the pluggable-optics runway open for years, supporting Lumentum, Coherent, Marvell, Applied Optoelectronics and Sivers even as co-packaged optics approaches. NVIDIA and Cisco co-designed a module with four times the bandwidth in the same slot; fewer modules per GPU look bearish, but the added optical content points the other way. x.com 

Copper scale-up is dead, making optics hyper bullish, especially Lumentum. Nvidia's Rubin NVLink Nyquist cut from 56 to 47 GHz signals failure: reflections matter, and bidirectional links make them worse. Feynman will have to use 16-wavelength DWDM ring-modulator CPO at roughly 50-64G NRZ. x.com  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 

Optics and photonics should be among AI's biggest winners as faster GPU networks need optical connections that suppliers cannot expand quickly enough. Lumentum says some components are sold out through early 2029; Sivers is investing $30M to target more than 100M lasers a year, with operations expected in Q4 2027. Potential US restrictions on Chinese transceivers could reshape supply in 2027. Applied Optoelectronics and Sivers are the favorites. x.com  x.com 

Coherent's booked InP laser capacity gives it a potential path into Nvidia's CPO expansion. Nvidia wants optical-engine capacity up 15x by mid-2027 and holds laser purchase commitments and capacity rights from its $2B Coherent investment. Coherent says fiscal 2027 is essentially booked and customers are reserving into 2028, but most near-term orders are for pluggables and other products; scale-up CPO revenue starts only in H2 2027. Neither company has sized Nvidia's rights. x.com 

Wafer-tested VCSEL arrays could erode Lumentum's laser scarcity premium if scale-up links adopt wide, parallel designs. Lumentum's in-rack demo used arrays but does not replace every high-power laser; Credo and ams OSRAM seek approval for a parallel-link standard in 2027. Multiple suppliers would pressure pricing power and margins. Near-term earnings could still benefit from laser shortages, with Lumentum sold out through early 2029. x.com 

Higher optical-fiber use per GPU could expand demand for Applied Optoelectronics. Corning said fully optical scale-up would raise fiber count from about 16 to 160 per GPU; that 10x case is hypothetical for now, with a mix of technologies likely near term, but it shows the direction of travel. x.com  x.com 

Optical networking's broader rollout will be slow because scale-up and scale-out require orders of magnitude more connections than today's limited optical distance links. Supply-chain discussions echo that slow pace. NPO/CPO starts in switches and reaches XPUs and GPUs much later, with new challenges. Optical backplanes will be necessary as racks move to optical, though copper will remain in many implementations. x.com  x.com  x.com  x.com 

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.com 

Optical transceiver demand exceeds supply, and 1.6T lifts revenue per module for suppliers able to qualify capacity. Applied Optoelectronics raised at least $1.62B through 2026 ATMs; its last reported monthly capacity was 200,000 modules versus a year-end target above 650,000. Credo expects over $600M in FY2027 revenue across optical DSPs, PICs and modules, not modules alone. Shipments, yields and margins must prove out. Lumentum and Coherent already price in much expected growth. x.com