Silicon photonics

Silicon photonics means building optical components using the same manufacturing methods as ordinary silicon chips, rather than assembling them from discrete optical parts. It matters as the substrate underneath everything else in the optics layer: scaling module volume and driving cost down increasingly depends on integrating the optics onto silicon so they can be made at wafer scale. As demand for high-speed links climbs, manufacturability — not raw performance — becomes the deciding factor in which optics technology can actually be produced in the quantities the buildout needs.

The hard part is integration, particularly coupling lasers to the silicon; limits there cap both volume and yield. That makes this a quiet gating layer beneath the flashier generation numbers. The firms working this substrate — Jabil, POET Technologies, Lightmatter, foundry Tower Semiconductor, STMicroelectronics and materials supplier Shin-Etsu — are positioned on whichever integration approach proves it can scale cleanly.