1/10

If you are studying CPO, NPO, silicon photonics, or AI optical networking,

you will keep seeing one term:

CW Laser

But before discussing $LITE, $COHR, or the optical supply chain,

we need to understand one basic question:

What does a CW Laser actually do?

This is a beginner-friendly explainer. 2/10

CW Laser = Continuous Wave Laser.

The core idea is simple:

It does not blink on and off to send data.

It continuously emits a stable beam of light.

Think of it like a light source that stays on.

1/9

The market is talking about “glass” again.

But this is not the same glass story.

Glass core helps stabilize advanced chip packages.

Glass cloth is used inside materials that become server PCBs.

Same word.

Different layer.

Different suppliers.

Different bottleneck.

Before interpreting the latest supply and pricing headlines, we need to understand where each one sits. 2/9

Start with a simplified AI server stack:

Silicon die / AI chip

↓

Package substrate

↓

PCB / motherboard

↓

AI server system

A chip does not simply connect directly to the large system PCB.

A much finer package substrate sits between the chip and the PCB.