# Fiber, connectors, structured cabling

Part ID: 3.11 · Layer 3 (Networking & interconnect)

The fiber optic cable, connectors, and structured cabling that carry optical signals between transceivers across a data hall or campus.

Fiber, connectors, and structured cabling is the physical medium the optical transceivers of 3.04 transmit over, running from switch to switch within a data hall and, via the DCI and coherent optics of 3.12, between buildings on a campus or between sites. MPO/MTP ferrules and connectors (3.11a) are the specific interface that lets fiber be broken out to individual transceiver ports and reconnected during maintenance or upgrades. AI data halls run substantially more fiber per rack than general-purpose facilities because of the higher port count per GPU described in 3.02–3.04, and higher speed grades tighten the tolerances the fiber and connectors have to meet. An investor should watch this as a relatively fragmented, lower-margin layer compared to the active optics above it, where scale and manufacturing footprint matter more than proprietary technology.

**AI delta:** Higher optical port counts per GPU and per rack in AI clusters increase the volume of fiber, connectors, and structured cabling needed per unit of compute deployed.

## Companies

| Company | Role | Confidence | Ownership | Ticker | Note |
|---|---|---|---|---|---|
| Belden | manufacturer | inferred | public | BDC |  |
| CommScope | manufacturer | inferred | public | COMM |  |
| Corning | manufacturer | inferred | public | GLW |  |
| Fujikura (AFL) | manufacturer | inferred | public | 5803.T | / AFL |
| Furukawa | manufacturer | inferred | public | 5801.T | / OFS |
| Hengtong | manufacturer | inferred | public | 600487.SS |  |
| Nexans | manufacturer | inferred | public | NEX.PA |  |
| Prysmian | manufacturer | inferred | public | PRY.MI |  |
| Sumitomo Electric | manufacturer | inferred | public | 5802.T |  |
| YOFC | manufacturer | inferred | public | 6869.HK |  |
| Leviton | manufacturer | inferred | private |  |  |
| Panduit | manufacturer | inferred | private |  |  |
| Siemon | manufacturer | inferred | private |  |  |

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