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204 points WithinReason | 1 comments | | HN request time: 0.195s | source
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yjftsjthsd-h ◴[] 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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AceJohnny2 ◴[] No.40713112[source]
> 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...)

You got it. We can't make optical transceivers as good as electrical ones. Not as small or power-efficient.

They require significantly different fabrication processes, and we don't know how to fab them into the same chip as electrical ones. I mean: you can either have photonics, or performant digital (or analog) electronics.

We've gotten really, really good at making small electronics, per the latest tech coming out of Intel & TSMC. We are... not that good at making photonics.

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1. alechammond ◴[] No.40717470[source]
> They require significantly different fabrication processes, and we don't know how to fab them into the same chip as electrical ones.

There are actually a few commercial fabs that will monolithically integrate the photonics, analog electronics, and digital electronics, all in the same CMOS process. See for example GF’s process:

https://www.cmc.ca/globalfoundries-fotonix-45spclo/

Integrating good optical sources in silicon remains a challenge, but companies like Intel have mastered hybrid bonding and other packaging techniques. TSMC too has a strong silicon photonics effort.