# Optics contract manufacturing

Part ID: 3.05 · Layer 3 (Networking & interconnect)

Contract manufacturers that assemble and test optical transceivers on behalf of module brands and switch vendors.

Optics contract manufacturing sits between the component layers that feed a transceiver (lasers in 3.06, DSPs and drivers in 3.07, silicon photonics in 3.08) and the finished, branded modules described in 3.04. Rather than every module brand running its own assembly lines, a handful of contract manufacturers build modules — including a GPU vendor's own branded optics — to the module brand's design, similar to how EMS providers build servers to an OEM's specification elsewhere in the stack. AI-driven optics demand has concentrated volume in this small group of manufacturers, since qualifying a new assembly and test line for the highest optical speeds is a slow, capital-intensive process. An investor should watch how tightly a given contract manufacturer is tied to a single large customer's volume, since that concentration cuts both ways: it can mean a durable, high-utilization relationship or a single-customer dependency.

**AI delta:** Surging optical module demand from AI clusters has concentrated assembly volume in the small group of contract manufacturers already qualified at the highest optical speeds.

## Companies

| Company | Role | Confidence | Ownership | Ticker | Note |
|---|---|---|---|---|---|
| Celestica | manufacturer | inferred | public | CLS |  |
| Fabrinet | manufacturer | inferred | public | FN | builds Nvidia's modules |
| Flex | manufacturer | inferred | public | FLEX |  |
| Jabil | manufacturer | inferred | public | JBL |  |
| Sanmina | manufacturer | inferred | public | SANM |  |

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