Optical Memory Could Speed Up the Internet 36
ananyo writes "Bits of data travelling the internet have a tough commute — they bounce back and forth between optical signal lines for efficient transmission and electrical signal lines for processing. All-optical routers would be more energy efficient, but their development has been hindered by a lack of optical memory devices. Now, researchers have developed just such a device (journal article abstract), paving the way towards a faster, more energy-efficient internet. The devices are based on optical cavities that can be switched between light-transmitting and light-blocking states to construct digital signals. Researchers have been working on such devices for several years, but previous versions used too much power and could not retain data long enough. The new memory cells use just 30 nanowatts of power, 300 times less than previous designs, and can retain data for one microsecond — long enough to support processing."
(See also this paper on all-optical swtiches by four of the same authors.)
Re:Nonsense (Score:4, Informative)
Re:Nonsense (Score:4, Informative)
Actual link latency doesn't effect throughput, while all the time spent going from optics->CPU->optics does. If you could build an all optical router, it would be theoretically capable of very good results. Also, fiber is frequently used for much shorter hops as well. We have hundreds of optical links at the place where I work, and that's all inside a very small room. If more of the infrastructure was 100% optical, that could improve things a lot over the next few years.
Re:Nonsense (Score:4, Informative)
Umm, do you know how fast the speed of light is? It's not speed that is the issue, it's the time requires to process the light which is the issue. If it takes 5ms to process light, that means that light has to be made in pulses of 5ms or else signal is lost. Longer pulses = longer travel time in a way. That is why processing purely in optical extremely important as conversion between optical to electron and back is slow in comparison to a pure optical router. When you have lots of routers between endpoints, speed is basically reduced down to switching speed which is the true bottleneck. Remove the switching and you remove the bottleneck. Now, it won't remove the switching speed at the endpoints but it does reduce the latency from switching that occurs in between.
Re:Lack of optical memory devices? (Score:4, Informative)
The researchers seem to have missed the huge leftover stock of photographic film. Stopping it completely provides indefinite storage while spinning it 1 mega frame / second satisfies microsecond processing needs.
I remember someone spinning a bit of metal at 10^6 rev/sec. It was the size of the period on a typewriter. At 1.5x10^6 or so it exploded. I suspect that the gelatin would spin off much earlier.