1.6T optics and CPO: realistic timelines for 2026 to 2028

On 27 July 2026 TrendForce reported that NVIDIA and Broadcom had begun the volume ramp of co-packaged optics (CPO) switches. NVIDIA had started shipping its next-generation Spectrum-X CPO switch, developed with TSMC on its COUPE packaging and offering up to 400 Tb/s of switching capacity, to selected partners, with capacity expected to grow in the second half of 2026. Broadcom was continuing limited shipments of its 51.2T Bailly CPO switch, which had entered volume manufacturing with Delta Electronics and Micas Networks and completed deployment validation with hyperscalers including Meta; TrendForce cited a power reduction of up to 70 per cent against pluggable transceivers.

The same report explains why this will not quickly become a mainstream purchase. TrendForce named three supply constraints: optical engines, whose yield and thermal requirements limit mass production to a few suppliers; silicon photonics capacity, which takes a long time to build; and advanced packaging, where CPO switches compete with AI accelerators for the same 2.5D and 3D capacity. Some hyperscalers are securing supply through long-term contracts and stakes in silicon photonics suppliers. TrendForce expects the CPO switch market to reach volume ramp in 2027 to 2028.

Pluggables move first

In the meantime, capacity growth runs through pluggable optics. Dell'Oro Group said on 2 June that 800G switches made up the vast majority of AI back-end Ethernet shipments in the first quarter of 2026, with 1.6T switches sampling and expected to ramp in the second half of the year. At OFC in March, Coherent demonstrated several 1.6T transceivers built on different laser and modulator technologies with DSPs from three partners, and showed 400G-per-lane links for future 3.2T modules as technology demonstrations rather than products.

The pluggable camp is also adapting to liquid cooling. On 12 March 2026 Arista announced the XPO multi-source agreement for a 12.8 Tbps, 64-channel liquid-cooled pluggable module with an integrated cold plate rated for up to 400 W. Arista gives 204.8 Tbps of front-panel capacity per OCP rack unit, which it describes as four times the density of 1.6T OSFP, and the format is meant to cover reaches from short-reach multimode to ZR and ZR+ coherent. No shipping date was given. Microsoft and Dell'Oro were quoted in support, and Dell'Oro's comment emphasised that the format keeps the serviceability of pluggable modules.

What it means for buyers

For enterprise and operator projects planned for 2026 and 2027, assume pluggable 800G and, from late 2026, 1.6T OSFP optics. Treat CPO as a hyperscale technology until the 2027–2028 ramp, and treat XPO as a design to watch rather than a product to specify. When ordering 1.6T, name the form factor, reach and the switch vendor's qualified part list, and ask for written lead times, since 1.6T supply is only now moving from sampling to volume. InTechnologies can quote 800G and 1.6T optics from OEM and compatible sources.