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Optical PCIe 7.0 connection hits 128 GT/s

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204 points WithinReason | 1 comments | 17 Jun 24 11:42 UTC | HN request time: 0.26s | source
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yjftsjthsd-h ◴[18 Jun 24 00:02 UTC] No.40712649[source]▶
So I guess what this makes me wonder is: Why are we using electrical signals to connect the data lanes between components and computers these days, rather than moving everything to optical for data movement (obviously power would stay electrical, but that's already on separate lines)? I assume there's an element of cost, and once the photons get where they're going they have to be turned back into electrical signals to actually be used until such time as we get around to getting pure light based computers working (someday but not yet...), but that must not overwhelm the advantages or we wouldn't be looking at this being developed.
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1. hinkley ◴[18 Jun 24 17:29 UTC] No.40720156[source]▶
I know when silicon photonics were brand new, they had a big limitation because they only had designs that fired out of the plane of the chip, not across it. That limits you to interconnects and not cross-chip signaling. And since for a CPU you need a heat sink on top that means you have to fire down, toward the motherboard.

Also it turns out the speed of light in glass is not that impressive. So encoding and decoding at the ends eats up the speed advantage. That’s my impression as to why a lot of high profile articles on optical logic came out shortly thereafter. What if we just keep it as light for longer?