# DCI / coherent optics (campus-to-campus, metro)

Part ID: 3.12 · Layer 3 (Networking & interconnect)

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.

## Companies

| Company | Role | Confidence | Ownership | Ticker | Note |
|---|---|---|---|---|---|
| Adtran | manufacturer | inferred | public | ADTN |  |
| Ciena | manufacturer | inferred | public | CIEN |  |
| Cisco | manufacturer | inferred | public | CSCO |  |
| Coherent | manufacturer | inferred | public | COHR |  |
| Lumentum | manufacturer | inferred | public | LITE |  |
| Marvell | manufacturer | inferred | public | MRVL |  |
| Nokia | manufacturer | inferred | public | NOK |  |
| ZTE | manufacturer | inferred | public | 000063.SZ |  |
| Huawei | manufacturer | inferred | private |  |  |

Confidence tags: disclosed = company/filing statement; reported = trade press or partner list; inferred = taxonomy lead.