Light-based computers in development
1–10 of 16 posts
Re: Light-based computers in development
#2The main problem is still getting strong optical nonlinearity to build optical only transistors. Right now best case 1 in 100 photons will be affected by most "switches". There's been some research using various resonators to enhance the nonlinearities, but that's really the big problem to solve right now.
There's also scaling issues - we have 20nm electrical switches, which is almost 50 times smaller than the wavelength of visible light, so you either need to go to deep UV or confine light to area much smaller than the free-space wavelength, which presents its own challenges.
My personal interest in optical computing is mainly in building optical quantum computers, in which case the cost/size/power of solving these challenges could be well worth it due to the scaling advantages of multi-qubit entanglement. Classical optical computing does not really seem that worth it if we need to build computer chips that are 1000 times bigger and run each operation on average 10^8 times to get a valid result, although the clock speed and power benefits would be nice.
Re: Light-based computers in development
#3The main problem is still getting strong optical nonlinearity to build optical only transistors. Right now best case 1 in 100 photons will be affected by most "switches". There's been some research using various resonators to enhance the nonlinearities, but that's really the big problem to solve right now. There's also scaling issues - we have 20nm electrical switches, which is almost 50 times smaller than the wavele…
This is what gets my juices going: http://arxiv.org/abs/1207.1619
All-optical Reservoir Computing
Re: Light-based computers in development
#4> The key advantage of light, made of photo[n]s, is it’s the fastest thing you can use to transfer information according to the professor.
I wish people would stop spreading this exaggeration. ~~Electrons~~ Electronic signals move at 0.66c. In practice 1c is unlikely to provide the most significant gains.
The key benefit is actually the energy efficiency that the article barely mentions, as well as massive reduction of interference within circuits (which is why you have to up the CPU voltage when you overclock).
Re: Light-based computers in development
#5> The key advantage of light, made of photo[n]s, is it’s the fastest thing you can use to transfer information according to the professor. I wish people would stop spreading this exaggeration. ~~Electrons~~ Electronic signals move at 0.66c. In practice 1c is unlikely to provide the most significant gains. The key benefit is actually the energy efficiency that the article barely mentions, as well as massive reduction…
I have to nitpick because that's a very frequent misconception as well: electrons, in fact, move very slowly in metals and semiconductors (a few cm/s at best). It's the electromagnetic waves that move so fast (depending on the material, it's going to be anywhere between 0.5c and 0.9c in most everyday appliances), but the electrons themselves are really slow.
Re: Light-based computers in development
#6> The key advantage of light, made of photo[n]s, is it’s the fastest thing you can use to transfer information according to the professor. I wish people would stop spreading this exaggeration. ~~Electrons~~ Electronic signals move at 0.66c. In practice 1c is unlikely to provide the most significant gains. The key benefit is actually the energy efficiency that the article barely mentions, as well as massive reduction…
I have to nitpick because that's a very frequent misconception as well: electrons, in fact, move very slowly in metals and semiconductors (a few cm/s at best). It's the electromagnetic waves that move so fast (depending on the material, it's going to be anywhere between 0.5c and 0.9c in most everyday appliances), but the electrons themselves are really slow.
Thanks, edited to clarify.
Re: Light-based computers in development
#7Earlier quoted context omitted.
I have to nitpick because that's a very frequent misconception as well: electrons, in fact, move very slowly in metals and semiconductors (a few cm/s at best). It's the electromagnetic waves that move so fast (depending on the material, it's going to be anywhere between 0.5c and 0.9c in most everyday appliances), but the electrons themselves are really slow.
Thanks, edited to clarify.
You're welcome :).
Re: Light-based computers in development
#8The main problem is still getting strong optical nonlinearity to build optical only transistors. Right now best case 1 in 100 photons will be affected by most "switches". There's been some research using various resonators to enhance the nonlinearities, but that's really the big problem to solve right now. There's also scaling issues - we have 20nm electrical switches, which is almost 50 times smaller than the wavele…
If efficiency is vastly improved, we can stack the layers and increase frequency by quite a bit. Even if the processor becomes a 10cm x 10cm x 10cm cube, it's okay as a proof of concept.
It's an interesting approach to overcome the inherient limitations of electron based circuits.
Re: Light-based computers in development
#9> The key advantage of light, made of photo[n]s, is it’s the fastest thing you can use to transfer information according to the professor. I wish people would stop spreading this exaggeration. ~~Electrons~~ Electronic signals move at 0.66c. In practice 1c is unlikely to provide the most significant gains. The key benefit is actually the energy efficiency that the article barely mentions, as well as massive reduction…
I have to nitpick because that's a very frequent misconception as well: electrons, in fact, move very slowly in metals and semiconductors (a few cm/s at best). It's the electromagnetic waves that move so fast (depending on the material, it's going to be anywhere between 0.5c and 0.9c in most everyday appliances), but the electrons themselves are really slow.
I always went with this:
Principle of physics is that Light and Electricity are the SAME THING. Electricity is just Light guided along wires. [http://scienceline.ucsb.edu/getkey.php?key=2910]
Than the following link shows that electricity moves about 1/100 the speed of light in wires:
Light travels through empty space at 186,000 miles per second. The electricity which flows through the wires in your homes and appliances travels much slower: only about 1/100 th the speed of light. Part of the reason is that light is massless; it has no weight, whereas the electricity flowing in the wires is made up of a stream of electrons, all of which have some small amount of weight. In addition, the electrons flowing through the wires constantly bump into the atoms of the wire, which slows them down considerably. If you were to take the electrons out of the wire and make them flow through space (which is essentially what you do when you make a spark), they can move faster, but no matter what, they cannot move as fast light. [Light travels through empty space at 186,000 miles per second. The electricity which flows through the wires in your homes and appliances travels much slower: only about 1/100 th the speed of light. Part of the reason is that light is massless; it has no weight, whereas the electricity flowing in the wires is made up of a stream of electrons, all of which have some small amount of weight. In addition, the electrons flowing through the wires constantly bump into the atoms of the wire, which slows them down considerably. If you were to take the electrons out of the wire and make them flow through space (which is essentially what you do when you make a spark), they can move faster, but no matter what, they cannot move as fast light. [Light travels through empty space at 186,000 miles per second. The electricity which flows through the wires in your homes and appliances travels much slower: only about 1/100 th the speed of light. Part of the reason is that light is massless; it has no weight, whereas the electricity flowing in the wires is made up of a stream of electrons, all of which have some small amount of weight. In addition, the electrons flowing through the wires constantly bump into the atoms of the wire, which slows them down considerably. If you were to take the electrons out of the wire and make them flow through space (which is essentially what you do when you make a spark), they can move faster, but no matter what, they cannot move as fast light.[http://scienceline.ucsb.edu/getkey.php?key=2910]]
Re: Light-based computers in development
#10> Light-based computers in development, to be millions of times faster
When will we see this millions time faster computers commercially available?
Maybe around the time when the thousands-times faster internet and 100 times larger batteries from articles I read years ago are available...