What is optical fibre?

1. Why it matters

Fibre is what makes the distance affordable. A modern AI campus contains an enormous quantity of it, and how densely it can be routed and connected sets how large a single cluster can physically be.

2. How it works

1. 1 Ultra-pure glass is drawn into a fibre with a core and a lower-index cladding.
2. 2 Light entering the core reflects internally and stays inside it.
3. 3 Fibres are bundled into cables and terminated with precision connectors.
4. 4 Cables are routed between racks, halls and buildings.

3. Inputs and outputs

Made of

Ultra-pure silica glass, protective coatings, cable structure and connectors.

Takes in

High-purity glass preforms and drawing capacity.

Produces

The physical network linking every accelerator in a cluster.

4. Where it gets stuck

The glass itself is rarely the constraint. Connector density, installation labour and the physical routes through a building usually are.

A general statement about the technology. It is not a claim about any named project — where T2C can evidence a specific delay, it appears in the intelligence ledger with its source.

5. Where it sits in the chain

1. Materials
2. Wafers
3. Chips + HBM
4. Photonics
5. AI Factory
6. Accepted
7. Revenue

T2C tracks the delivery end of this chain. An upstream stage is shown as having happened — capacity cannot be billing unless the parts were made — and simultaneously as untracked, because no supplier, order or shipment record sits behind it.

6. Public companies in this area

These companies make the components this stage depends on. Except where a row states a named agreement or a disclosed order, no document links them to any operator, site or contract T2C tracks — making a component is not the same as having been awarded work, and this table never implies otherwise.