MIT Researchers Make Advance Toward Photonic Circuits 55
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Unknown Lamer
from the look-into-the-light dept.
from the look-into-the-light dept.
MrSeb writes with this excerpt from an article in Extreme Tech: "Light-emitting diodes are a cornerstone of consumer tech. They make thin-and-light TVs and smartphones possible, provide efficient household, handheld, and automobile illumination, and, of course, without LEDs your router would not have blinkenlights. Thanks to some engineers from MIT, though, a new diode looks set to steal the humble LED's thunder. Dubbed a diode for light, and crafted using standard silicon chip fabrication techniques, this is a key discovery that will pave the path to photonic (as opposed to electronic) pathways on computer chips and circuit boards. The diode for light — which is made from a thin layer of garnet — is transparent in one direction, but opaque in the other. Garnet is usually hard to deposit on a silicon wafer, but the MIT researchers found a way to do it."
The MIT article is much better... (Score:5, Informative)
It doesn't go off and start talking about LEDs and WDM which just confuses the issue.
http://www.mit.edu/newsoffice/2011/optical-computing-diode-1123.html [mit.edu]
Re:Interesting concept (Score:4, Informative)
Well, much of the leaking in traditional electronic transistors is due to quantum mechanical effects, which would still apply to photonic devices. (With differences arising from such things as spin.) Some people are using evanescent fields from thin fibre lines to actually couple the signals in the line to other devices.
Re:I have lots of questions (Score:5, Informative)
Fortunately, the kids at ExtremeTech were good enough to at least link the original which isn't nearly as confusing.
Re:I have lots of questions (Score:4, Informative)
It's not a Light Emitting Diode, it's basically a Light Diode. Light can only pass through in one direction. The way this is normally done is by rotating the polarization of light through two polarizers. [wikipedia.org] Any light of the wrong polarization cannot return back to the light source. This is usually used to protect laser sources and their modulators from return loss reflections in fiber optic systems that make use of polarization maintaining fibers.
Anyway, a 'true' optical transistor can be fashioned out of this if coupled with an optically controlled gain medium. If you have optical transistors, you can create optical NOR or NAND gates, and all basic logic functions can be created solely from these gates.
Just skimming the actual Nature paper itself, it appears they've basically created an optical isolator on a planar optical waveguide circuit.
To answer your last question: no.
You'd be better off with black construction paper for that.