VCs Bet on AI Chips That Use Light Instead of Electronics

When Nvidia CEO Jensen Huang in March said his company would release hardware that lets an AI data center chip send information directly over optical cables instead of needing to convert to optical from electrical signals, it was a shot in the arm for optics developers that have long wanted a bigger role in data centers.

Using light to send information over fiber optic cables is well-established, but attempts to use light for computation in data center servers have struggled. Some investors now think the time is right to use optical technology for active computation in the chips themselves, instead of just using it to ferry data between chips.

The idea is that light can encode information in its wavelength, amplitude and phase. By bouncing light off a clever arrangement of mirrors and other devices, for instance, and allowing the beams of light to interact, the light can perform addition and multiplication—essentially replacing traditional electronic chips. 

Compared to moving electrons in copper wires or transmitting radio waves over the air, sending light through fiber optics “is both very contained, very fast, and a piece of fiber is like the size of a strand of hair,” said Bill Long, chief strategy officer at Zayo, which provides fiber optic connections, including to AI data centers.