In datacenters people use optics for longer distances (10m to 2km). Within a rack it is almost always copper. The reason is that for short distances lasers are too expensive, unreliable, and consume too much power. We think microLED based links might replace copper at short distances (sub 10m). MicroLEDs into relatively thick fiber cores (50um) are much easier to package than standard single mode laser based optics.

on the distance - exactly right. The real bottleneck now in AI clusters is the interconnect within a rack or sub 10m. So that is the market we are addressing.

On your second point - exactly! Normally people think LEDs are slow and suck. That is the real innovation. At Avicena, we've figured out how to make LEDs blink on and off at 10Gb/s. This is really surprising and amazing! So with simple on-off modulation, there is no DSP or excess energy use. The article says TSMC is developing arrays of detectors, based on their camera process, that also receive signals at 10Gb/s. Turns out this is pretty easy for a camera with a small number of pixels (~1000). We use blue light, which is easily absorbed in silicon. BTW, feel free to reach out to Avicena, and happy to answer questions.