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New Optical Switch Up to 1000x Faster Than Transistors

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Re: New Optical Switch Up to 1000x Faster Than Transistors

#81

Post by BenjiWiebe »

vbezhenar wrote: post #61
jrootabega wrote: post #59

Earlier quoted context omitted.

So they were right about computers the size of entire buildings, they were just off by 100 years?

1 GHz allows for photon to move 3 m per cycle in vacuum. 10 GHz is 30 cm. Even less in fiber cable. I think that's a fundamental restriction of a size of an individual computing module. Of course you can stack modules in entire buildings just like you can stack cpus in servers in data center now.

Perhaps I'm misunderstanding your comment, but the frequency doesn't change the speed of light.

Re: New Optical Switch Up to 1000x Faster Than Transistors

#82

Post by WithinReason »

SmooL wrote: post #78
WithinReason wrote: post #73

Earlier quoted context omitted.

This makes me wonder if transmitting data optically would help with the gradual lowering of the data/compute ratio over time: https://sites.utexas.edu/jdm4372/files/2016/11/Slide16.png

We already transmit data optically, that's what fiber optics is.

I'm talking about between chips and RAM of course because that's where the data/compute ratio is shrinking, not between Tokyo and New York.

Re: New Optical Switch Up to 1000x Faster Than Transistors

#83

Post by tremon »

wnkrshm wrote: post #51
dogber1 wrote: post #5

In reality, all-optical computing is mostly a terrible idea: fundamentally, it cannot reach the integration density of electronics. It boils down to the elementary differences between Fermions (electrons, neutrons, etc.) and Bosons (photons, etc.). Their intrinsic behavior determines the interaction with matter, i.e. conductive/absorptive properties. As a result, optical wires (waveguides) have to be sized roughly at…

The flipside is switching speed, optically you can reach THz and more apparently, while heat/capacitance/crosstalk limit electronic transistors IIRC.

Yes, signal (non-)interference is a big upside to optical communication. Photon streams don't interact even when passing through the same waveguide, so you can superimpose many bits/streams/connections in the same transmission channel at the same time (using varying wavelengths or polarisation), and two optical channels running side-by-side don't exert a magnetic force on each other either.

The main upside for optical processing (photonics) is in signal switching then, as in this case. Having to receive the multitude of optical signals, converting them to electrical, doing the signal routing and processing in the electrical domain, then converting back to optical for transmission is a lot of busywork.

Re: New Optical Switch Up to 1000x Faster Than Transistors

#84

Post by tremon »

BenjiWiebe wrote: post #81
vbezhenar wrote: post #61

Earlier quoted context omitted.

1 GHz allows for photon to move 3 m per cycle in vacuum. 10 GHz is 30 cm. Even less in fiber cable. I think that's a fundamental restriction of a size of an individual computing module. Of course you can stack modules in entire buildings just like you can stack cpus in servers in data center now.

Perhaps I'm misunderstanding your comment, but the frequency doesn't change the speed of light.

They're talking about wavelengths ("per cycle"). But I'm not sure it makes more sense knowing that, since there's a fundamental disconnect between the signal frequency and the carrier frequency. I think QAM can even be used on a signal rate that's higher than the carrier frequency (as long as the carrier frequency is known), but I'm not 100% sure.

Re: New Optical Switch Up to 1000x Faster Than Transistors

#85

Post by adgjlsfhk1 »

WithinReason wrote: post #82
SmooL wrote: post #78

Earlier quoted context omitted.

We already transmit data optically, that's what fiber optics is.

I'm talking about between chips and RAM of course because that's where the data/compute ratio is shrinking, not between Tokyo and New York.

the hard part is that currently electrical to optical conversions take a fair amount of space which would make them hard to do on CPU. it might be practical for storage to ram though, which would be really cool.

Re: New Optical Switch Up to 1000x Faster Than Transistors

#86

Post by marcosdumay »

dogber1 wrote: post #5

In reality, all-optical computing is mostly a terrible idea: fundamentally, it cannot reach the integration density of electronics. It boils down to the elementary differences between Fermions (electrons, neutrons, etc.) and Bosons (photons, etc.). Their intrinsic behavior determines the interaction with matter, i.e. conductive/absorptive properties. As a result, optical wires (waveguides) have to be sized roughly at…

Well, good thing that the proposed application is about multiplexing/demultiplexing, and not about general computing.

Light has many inherent advantages over electricity for multiplexing/demultiplexing. Also, optical amplification works quite well too, and people use it on every long distance data cable nowadays.

Re: New Optical Switch Up to 1000x Faster Than Transistors

#87

Post by rasguanabana »

Goz3rr wrote: post #46
rasguanabana wrote: post #39

Earlier quoted context omitted.

It’s not all about computing. It’s about avoiding conversion from electrical to optical signal (and back) at every network node, which is costly.

Don't you need a certain amount of computing at each network node anyways to see what to do and where to send the optical signal next? In additional to error correction/amplifying the signal?

Often it might be as simple as routing right wavelength through right path, as in WDM systems. Optical amplifiers, such as EDFA [0] are interesting thing, too.

[0]: http://www.fiber-optical-networking.com/the-application-of-e...

Re: New Optical Switch Up to 1000x Faster Than Transistors

#88

Post by anfilt »

dogber1 wrote: post #5

In reality, all-optical computing is mostly a terrible idea: fundamentally, it cannot reach the integration density of electronics. It boils down to the elementary differences between Fermions (electrons, neutrons, etc.) and Bosons (photons, etc.). Their intrinsic behavior determines the interaction with matter, i.e. conductive/absorptive properties. As a result, optical wires (waveguides) have to be sized roughly at…

While for most things density is good. However if you can have a certain task take advantage of this insane switching frequency there could be reasons to build a room or multi-room sized specialized computer. Not everything needs to be tiny for every application.

Also path delay is not an issue if you have a task that can be pipelined for raw through put. Latency is less of issue in such scenarios.

So claiming there is no use for such things seems a stretch. It certainly can have niche uses. Bigger problem with a lot these papers is their tech needs to be at least reasonable to manufacture to have niche uses.

Re: New Optical Switch Up to 1000x Faster Than Transistors

#89

Post by beebeepka »

georgeburdell wrote: post #26
dogber1 wrote: post #5

In reality, all-optical computing is mostly a terrible idea: fundamentally, it cannot reach the integration density of electronics. It boils down to the elementary differences between Fermions (electrons, neutrons, etc.) and Bosons (photons, etc.). Their intrinsic behavior determines the interaction with matter, i.e. conductive/absorptive properties. As a result, optical wires (waveguides) have to be sized roughly at…

You can't directly compare optical and electrical compute through looking at the difference in feature densities. Optical compute will most likely take the form of analog waveforms that contain many bits of information, whereas electronics for computing is inherently binary.

Isn't digital just an abstraction on top of analog anyway? Pretty much all electronics isime that

Re: New Optical Switch Up to 1000x Faster Than Transistors

#90

Post by beebeepka »

BenjiWiebe wrote: post #81
vbezhenar wrote: post #61

Earlier quoted context omitted.

1 GHz allows for photon to move 3 m per cycle in vacuum. 10 GHz is 30 cm. Even less in fiber cable. I think that's a fundamental restriction of a size of an individual computing module. Of course you can stack modules in entire buildings just like you can stack cpus in servers in data center now.

Perhaps I'm misunderstanding your comment, but the frequency doesn't change the speed of light.

Point is that interconnect between floor 1 and 5 might pose considerable challenges, thus greatly minimizing the potential advantages of having massive building sized computers
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