Yuanjie Semiconductor Technology — AI supply-chain exposure

Yuanjie designs and fabricates the tiny laser chips that sit at the heart of an optical transceiver — the indium phosphide diodes, including distributed-feedback types, that turn electrical signals into the light pulses carrying data between switches and servers. It is part of China's effort to localize a component long supplied by a handful of Western and Japanese specialists, moving the country up from merely packaging transceivers toward making the laser itself.

Inside an AI cluster, the fabric that lashes accelerators together runs on optics, and every optical link needs a laser. The laser chip is the scarce, high-value core of the module — hard to make, yield-sensitive, and built on indium phosphide rather than ordinary silicon. That places Yuanjie on a specialised upstream rung: not central to the whole build-out, but exposed to the relentless growth in optical connections that larger training clusters demand, and to Beijing's push to source those lasers at home.