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Light-emitting transistor uses light to transfer an electrical signal
physorg.com — In one of the early discoveries of the current "silicon electrophotonics era," scientists from Hitachi, Ltd. in Tokyo have built a light-emitting transistor (LET) that transfers, detects and controls an electrical signal all on a single nanometer-sized chip. Using a silicon-on-insulator (SOI) substrate, the group could optically connect the LET ..
aaaz- 321 diggs
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- vertinox, on 10/12/2007, -9/+3Very interesting. Hopefully it will lead to better solar technology.
But please slow down on submissions aaaz.- gianttacommk, on 10/12/2007, -1/+4Vertinox, he's just contributing to the digg community. This is very informative article.
- geminitojanus, on 10/12/2007, -0/+7Don't think it's going to do so much for the photovoltaics industry, but it might be a huge part of future photonic-based computers (which use silicon lasers instead of electrons to transfer information around the chip).
- BlackLineFish, on 10/12/2007, -6/+2Yes, it was interesting.
But please slow down on comments Vertinox...
http://digg.com/users/vertinox/commented
(just kidding, sort of)
--gh
- noouch, on 10/12/2007, -0/+4Isn't this esentially what an optocoupler does, just smaller?
- HappyScrappy, on 10/12/2007, -0/+3Yep,it appears to be just the world's smallest optocoupler.
Although I dunno if it isolates as well as a regular optocoupler because both signals are on the same substrate.
- HappyScrappy, on 10/12/2007, -0/+3Yep,it appears to be just the world's smallest optocoupler.
- fly40r, on 10/12/2007, -0/+0What's cool about this is, the same fabrication process and materials can be used to optically couple circuits on the same substrate, whereas (if I understand correctly) the process and materials used to make an LED are different than those typically used for logic circuits. Also seems to be faster, and allows for electrical isolation between circuits e.g. potentially less noise from substrate currents etc.
m - Heiios, on 10/12/2007, -0/+1Wow this is actually going to be a tremendous leap forward for electronic geeks. I wish more people understood how important this is.
- deepsub, on 10/12/2007, -2/+2As others have mentioned, this is just a glorified opto-coupler/isolator.
http://en.wikipedia.org/wiki/Opto-coupler
Light cannot transfer 'electrical signals'.... The whole point of using light to transmit signals is to eletrically isolate the involved elements.
Photons != Electrons
Light can -control- electrical signals.
/move on nothing to see here- geminitojanus, on 10/12/2007, -0/+2"Light can't transfer 'electric signals'"
Light is used almost every day to send signals (information) from point A to point B, I'm guessing you've never heard of Fiber Optics? The problem is designing a light-based "transistor", or switch element, which at current can't be done. This is the in-between step that can help unite silicon and light-based technologies; yes, it is a glorified half of an opto-coupler (it doesn't have two circuits; in an opto-coupler, you have one circuit connected to an LED and a second circuit connected to a photodiode, in this device you have a PNP-like transistor that emits light whenever it receives electricity at its junction. If you imagine how an opto-coupler works, it's the photo-diode side they've engineered, only with the reverse action of a normal photo-diode).
Some day in the future, using this technology combined with silicon lasers and MEMS/Nano Electro-Mechanical Systems (NEMS), we will be able to build optical-based computers like those in Star Trek, and this technology is an important step in that direction. Optics is a huge win over electrical based systems because light can travel through which there is no medium and thusly doesn't cause heat nor propagation delays, nor resistance/wire delay. Optical-based computers will also be better for space exploration, as electrical systems are more prone to pick up stray electromagnetics, whereas an optical computer simply can't pick up stray optics (because light travels in a straight line, using visible optics and a dark plastic you can shield the computer from solar radiation; the light simply can't enter the system).
So there's plenty to see here. Please don't move along, stay awhile, read the article.
- geminitojanus, on 10/12/2007, -0/+2"Light can't transfer 'electric signals'"
- TheWedge, on 10/12/2007, -0/+2While this is nice, having electrons involved in the transistor process at all is still going to be a bottleneck. An all optical transistor would be considerably faster considering that light travels significantly faster than electrons.
- inmatarian, on 10/12/2007, -0/+2Yeah, kind of. I seem to remember the speed of an electron being 99.9995% of light. So, yes, light is faster. :)
- TheWedge, on 10/12/2007, -0/+2If electrons in MOSFET channels moved at 99.9995% the speed of light, processor speeds would most definitely not be capped around 3 point something GHz. Newer, HEMT designs with near ballistic transport in the wires/channels can theoretically be clocked at 150 GHz (excluding any correction for multiple gate delays). Pure light transistors could probably be clocked anywhere in the terahertz to petahertz range (a pure guess - this depends on many factors).
- Yeyui, on 10/12/2007, -0/+3[edit: failed to reply to the right post because the login page doesn't send you back to where you came from...]
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