Light vs Copper

The blinking box on your wall is a slow optical module. The 800G ones filling switch faceplates in an AI cluster are the same symmetric signal chain, just run a few dozen times faster.

Networking has its own Moore's law, and AI's appetite for bandwidth outruns it. Copper's loss climbs with frequency while fiber's loss ignores speed but charges a fixed conversion toll — the two cost lines cross, and every generation the crossover slides toward shorter distances.

Kevin compresses nearly two centuries of wired communication into three shifts. Copper losing to glass was settled by physics; the fifty years since have been the boundary between them moving toward the chip, one step per speed generation.

Pluggable, LPO, NPO, CPO, OIO — five packaging schemes that are really one siting problem, how close to the office tower to build the courier depot. The optical DSP is the module's brain and its biggest power draw, and it sits at the center of the fight.

From a glass fiber pulled over an alcohol burner in 1976 to seven of the world's top ten module vendors, China built its optical industry in reverse order — cable first, then equipment, then modules, and only now the chips at the top. The module business is won; the high-end silicon above it still isn't.