With 512K-GPU clusters becoming the norm for AI factories, copper is hitting its limits. An OFC 2026 panel showed how CPO delivers a 3.5X efficiency gain, and how the 12.8T XPO rewrites the switch-density game.

As copper interconnects hit their physical limits, NPO is emerging as the practical lifeline for AI compute clusters. Tencent and Alibaba plan to start 3.2T NPO deployment by late 2026, while Huawei proposes a 7.2T spec aligned with GPU roadmaps.

When does copper run out? At OFC 2026, Meta answered with 90 million device-hours of field data: CPO cuts link power by 65% and, excluding one fixable component issue, is more than 10x more reliable than pluggable modules.

This week the market read SemiAnalysis's CPO-delay report as a death knell for optical components. It read it backwards. If CPO ramps a year later, pluggable optical modules — and the upstream EML lasers already sold out through 2027 — get an extra year of earnings. Demand hasn't weakened; only the oversold share prices have.

Conventional EDA is hitting a bottleneck when simulating silicon photonics. At OFC 2026, GF and Cadence presented photonic-native modeling built on waveguide scattering physics, delivering 2x faster simulation and paving the way for large-scale electro-photonic integration in the 1.6T era.

Scale-up optical interconnect looks like a seven-way melee, but there are really only two strategies, Fast-and-Narrow and Slow-and-Wide, each hitting a symmetric wall. Learn the yardstick first, then see how the seven approaches layer and coexist.

This week the bull case for optical communications got a new spokesperson: Broadcom's income statement instead of analyst decks. Demand is now locked in by earnings, but what's truly scarce can't be bought with earnings: the hardest bottleneck in the chain is a laser in short supply through 2027. The more real the demand, the more valuable the light source.

AuthenX (7928) uses metalenses to widen FAU alignment tolerance to ±18µm, tackling CPO's hard-to-align, hard-to-repair, hard-to-scale problems. The technology is compelling, but who owns the "patented metalens" and whether it clears certification and yield are open questions to settle before investing.

CPO is a bet on more than a dozen paths: the Big Four enter via scale-up, switch silicon, custom engines and optical I/O, while challengers stake out optical I/O chiplets, photonic interposers and microLEDs. But they share one supply chain — great specs don't guarantee a path to volume. This is a CPO scorecard.

Once the laser is moved off the chip, someone has to catch that +20 dBm high-power light. AIST shows that polymer waveguides on low-cost glass-epoxy substrates can do it: zero degradation over six hours and only a 4.4°C temperature rise — a key feasibility endorsement for the packaging-centric CPO route.

For a decade, photonics packaging was the last mile of assembly that nobody talked about. AI has pushed it center stage, with the market set to grow from $4.5B to $14.4B in six years — driven not by transceivers but by three new tracks opening at once: CPO, AR microLED and FMCW LiDAR. Part 1 of the series lays out the big picture.

Light leaks a little at every interface, and coupling is where CPO's optical losses concentrate, an invisible ceiling on yield and serviceability. Doubling V-groove density, edge vs. grating coupling, passive vs. active alignment: this unglamorous layer is where volume-production gaps open up.

Silicon photonics interconnects are hitting an inflection point. At OFC 2026, GlobalFoundries showed how detachable connectors and 3D packaging tackle the 100+ fiber assembly challenge in AI inference, while building a complete US-based optical packaging ecosystem.

As copper can no longer keep up with the data movement demands of AI clusters, Marvell answers with its Photonic Fabric optical platform. This is not just a speed upgrade, but an architectural shift that breaks through the memory wall and the power bottleneck.

In the era of gigawatt AI factories, the network defines the computer. NVIDIA unveiled 3D-stacked silicon photonics CPO and industry-leading MRM technology to break through the power and reliability limits of AI scaling, and laid out a decade-long roadmap fusing compute and optics.

Silicon photonics' original sin is that it can't emit light. Lasers hate heat, yet CPO asks them to sit next to a hot chip — making the light source the reliability ceiling, where one failed laser can cost an entire optical engine. External vs integrated sources and four light-source types each bet on a different future.

The CPO era has officially begun, with Cignal AI forecasting a $1.5B opportunity by 2030. Beyond the push from Nvidia and Broadcom, STT argues that CoS packaging for high-power lasers is the hidden barrier that will decide who wins ELSFP volume production.

Copper's physical limits have become the bottleneck to scaling AI. At OFC 2026, Broadcom showed its latest CPO and OCI progress - ultra-low 6 pJ/bit power and exceptional reliability - signaling that optics will dominate both scale-out and scale-up networks.

The AI compute race has entered its second half, and bandwidth and power are now make-or-break. Intel's OCI chiplet at OFC 2026 signals that the convergence of photonics and electronics at the chip level has arrived, rebuilding data center architecture rather than merely improving specs.

A major step for CPO external laser sources: at OFC 2026, Furukawa Electric showed an 8-channel TOSA delivering up to +25 dBm per channel, using a long-cavity design to solve high-power thermal limits and pave the way for 1.6T switch deployments.