Corkscrew optics yield direct line to electronics

https://spectrum.ieee.org/optical-computing-picosecond-gates

by mfiguiere • 4 years ago

74 21 4 years ago

spectrum.ieee.org

Actual paper: https://www.science.org/doi/10.1126/sciadv.abq8246

- "The new gates performed at speeds of less than 100 femtoseconds, which is roughly 1 million times as fast as electronic gates"

Electronic gates switching at 10 MHz?

amelius• 4 years ago

1 femtosecond = 1e-15 seconds.

perihelions2• 4 years ago

Right, so 100 fs = 1e-13 seconds. And a million times slower than that would be 1e-7 seconds, or (10 MHz)^{-1}.

oh_my_goodness3• 4 years ago

Yeah, they're off by a factor of 1000.

There are other serious technical errors in the piece too. For example they say "because photons move at the speed of light and electrons don't" ... which is irrelevant because electronic signals do move at the speed of light.

The most serious problem is missing context. It's been known for decades that you can build shockingly fast optical switches and even amplifiers. A hundred fs is fast but not unique. The problem is how to connect these devices in a complicated circuit without putting nanoseconds of waveguide in between. Unfortunately 1 ns is 1,000,000 fs.

So in telecom, where you're just going a long way in one direction, optical amplifiers with multi-THz bandwidth have dominated transport since the 1990s. But in computers, no.

blep_• 4 years ago

Electronic signals also do not move at the speed of light: https://en.wikipedia.org/wiki/Velocity_factor

teleforce2• 4 years ago

I think you're missing the bigger picture. While they're both EM but they're significantly different i.e. photon are much more desirable than electron.

For starter, for electron you have contention in the form of collision but there's no collision for photon. Imagine you have vehicles that can go pass through each other without any collision, they will be exponentially faster than the one's without this capability.

photochemsyn2• 4 years ago

Probably just a miscommunication. The actual improvement is more like 10K times, but this moves from the 'gigahertz range' to the 'petahertz range' which differ by 1e6.

"Since light oscillates so fast (roughly a few hundred million times per second), using light could speed up electronics by a factor of roughly 10 000 as compared to computer chips,” says Tobias Boolakee, a laser physicist in Peter Hommelhoff’s group at the FAU and the first author of a study in Nature on the new gate." (2022)

https://physicsworld.com/a/logic-gate-breaks-speed-record/

oh_my_goodness3• 4 years ago

Light oscillates much, much faster than a few hundred million times per second. Take 1 micron wavelength. At a speed of 3e8 m/s, 1 micron light oscillates 3e8/1e-6 = 3e14 times per second. Three times ten to the fourteenth power.

For anybody who doesn't juggle large numbers every day, a hundred million is 1e8. Ten to the eighth.

tiagod2• 4 years ago

I remember this exact issue in the last HN front-page article about optical gates, weeks ago...

airstrike• 4 years ago

Do you have a link? Would love to read that

naturedivine• 4 years ago

Perhaps we can use fewer optical gates and serialize the use of gates, using pipelining at gate level.

mikewarot• 4 years ago

The problem I see is that at these types of speeds, timing skew is going to be a crucial issue. Latency will dominate the design. I can see a design much like early computers with delay lines used as RAM. You could keep a series of packets in a fiber, and then operate on it at the appropriate time.

hoc• 4 years ago

I always found circular polarisation with its "natural" complexity one of the most fascinating aspects of generally available optics. Really happy about this practical use case and application of its properties.

Might sound a bit odd, but sometimes there is some kind of beauty in a certain design or basic approach.

Corkscrew optics yield direct line to electronics

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