Part of the day: DCI / coherent optics

Assembled by the nightly build from this catalog’s own entry for DCI / coherent optics (3.12, Layer 3 — Networking & interconnect). The tables below are rebuilt every night; first published 2026-09-15, refreshed 2026-09-24.

Coherent optical systems that carry data center interconnect (DCI) traffic between buildings on a campus or between metro sites, distinct from the shorter-reach optics inside a data hall.

DCI and coherent optics extend the network beyond the fiber and connectors of 3.11 that serve a single data hall, linking separate buildings on an AI campus or connecting sites across a metro area. This is a distinct technology from the direct-detect optics used inside a data hall (3.04): coherent transmission encodes more information per wavelength to cover longer distances, and the vendor base for coherent systems overlaps only partly with the vendor base for short-reach transceivers. As AI campuses grow beyond a single building and hyperscalers link multiple sites into one logical training cluster, demand for campus-to-campus and metro-scale coherent capacity grows with them. An investor should watch supplier concentration here separately from the rest of the optics stack, since coherent DCI has historically been a smaller, more specialized market than short-reach data center optics.

AI delta: Multi-building AI campuses and multi-site training clusters push more traffic onto campus-to-campus and metro coherent links than single-building data centers required.

Who makes it

The full entry — sub-categories, news, videos and sources — lives on the DCI / coherent optics page.