A deep dive into co-packaged optics (CPO) — NVIDIA Spectrum-X Photonics switches (SN6810 102.4 Tbps, SN6800 409.6 Tbps, Spectrum-6 ASICs), the ~3.5x power and ~10x reliability gains over pluggable transceivers, why they ship liquid-cooled, the 2025–2026 CPO news timeline, and the full supply chain making them: $NVDA, $AVGO, $TSM, $COHR, $LITE, $FN, $POET, plus the LPO/AEC camp ($CRDO, $ALAB).
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Co-packaged optics integrates the optical engine — the part that converts electrical signals to laser light — directly onto the same package as a switch or accelerator chip, instead of housing it in a separate pluggable transceiver module. This shortens the electrical path, cuts power, and improves reliability, which is why it's being adopted for the highest-bandwidth AI networking switches.
At 800G and 1.6T per port, pluggable transceivers consume too much power and fail too often to scale to clusters of hundreds of thousands of GPUs. The optical transceivers in a large AI fabric can burn megawatts on their own. CPO addresses both: NVIDIA cites roughly 3.5× better optical power efficiency and ~10× better network resiliency versus pluggables — power and uptime that translate directly into more usable GPUs.
Four step-changes versus pluggable transceivers, per NVIDIA: ~3.5× better optical power efficiency, ~63× better signal integrity (the ASIC-to-optics electrical loss drops from ~22 dB to ~4 dB), ~10× better network resiliency from 4× fewer, externally mounted lasers, and ~1.3× faster deployment. Broadcom's production data at Meta backs the power claim at roughly 65–70% optics power savings.
Quantum-X Photonics (InfiniBand) began shipping in early 2026 at low volume after slipping from late 2025. The first Spectrum-X Photonics Ethernet switches (SN6810, SN6800) started reaching select partners in June 2026, with the production ramp in the second half of 2026. Broadcom's CPO line has been shipping longer — Bailly since 2024–25 and Tomahawk 6 "Davisson" since October 2025.
The switch/integrator layer is led by NVIDIA ($NVDA), with Broadcom ($AVGO), Marvell ($MRVL), and Cisco ($CSCO) competing. The photonics are fabbed by foundries led by TSMC ($TSM), with GlobalFoundries ($GFS) and Tower ($TSEM). The optical engines, lasers, modulators, and assembly come from Coherent ($COHR), Lumentum ($LITE), Fabrinet ($FN), POET ($POET), Applied Optoelectronics ($AAOI), MACOM ($MTSI), and Lightwave Logic ($LWLG), plus private players like Ayar Labs. Fiber and connectors come from Corning ($GLW) and TE Connectivity ($TEL).
Because they pack extreme power density — NVIDIA's Quantum-X Photonics is 3.95 kW in a 4U chassis — and co-packaging puts heat-sensitive optics next to the hottest silicon. Air cooling struggles to move that much heat while keeping the lasers in their stable temperature range, so NVIDIA's CPO switches ship with direct liquid cooling, extending the same loops the GPUs already use (Broadcom's lower-density 51.2T Bailly systems remain air-cooled). That makes cooling names like Vertiv ($VRT) downstream beneficiaries.
CPO removes the pluggable module entirely. LPO (linear-drive pluggable optics) keeps a pluggable module but removes its power-hungry DSP. AEC (active electrical cables) replaces short optical links with signal-boosted copper. CPO wins on power and density for the largest switches; LPO and AEC ($CRDO, $ALAB) compete for shorter reaches and more conservative deployments. They coexist today.
It's one of the most direct ways to play AI networking, but it's a component-supplier theme with real cyclicality and customer-concentration risk (a few hyperscalers and NVIDIA drive demand). The diversified approach is to track the layer — the Photonics / CPO basket — rather than betting on a single design win. This is not financial advice.