AI data centers ran out of copper. Moving 800 gigabits between racks now means moving light, and every one of those links needs a laser, a module, a photonic chip, and the glass in between. Five layers, from the companies that make photons to the instruments that certify them.
Everything downstream starts with a photon. Lumentum and Coherent build the lasers and optical pumps that feed transceiver modules; IPG Photonics builds the high-power fiber lasers used in industrial and defense systems.
The pluggable optics that convert electrical signals to light and back at 400G, 800G, and 1.6T. This is the layer AI data centers are consuming fastest, and where Coherent, Lumentum, and Applied Optoelectronics compete directly. Fabrinet is the contract manufacturer that physically builds much of the industry’s output.
Putting optical functions onto silicon. Broadcom and Marvell ship the DSPs and optical engines inside modules and switches; Corning supplies the optical fiber and glass that the light travels through.
The boxes and switches that carry traffic between and inside data centers. Ciena builds coherent optical transport for long-haul and data-center interconnect; Arista and NVIDIA build the switching platforms that consume optics by the millions of ports.
The compound-semiconductor substrates the lasers are grown on, and the instruments that qualify every module before it ships. AXT supplies indium phosphide and gallium arsenide wafers; Keysight and Viavi build the optical test and measurement systems.
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