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Researchers build optical transistor out of silicon, provide path to all-optical computing
The speed of light is the universal speed limit, so naturally, optical technologies appeal when trying to construct speedy computational devices. Fiber optics let us shoot data to and fro at top speed, but for the time being our CPUs still make their calculations using electronic transistors. Good news is, researchers from Purdue University have built an optical transistor out of silicon that can propagate logic signals -- meaning it can serve as an optical switch and push enough photons to drive two other transistors. It's constructed of a microring resonator situated next to one optical line that transmits the signal, and a second that heats the microring to change its resonant frequency. The microring then resonates at a specific frequency to interact with the light in the signal line in such a way that its output is drastically reduced and essentially shut off. Presto, an optical transistor is born. Before dreams of superfast photonic computers start dancing in your head, however, just know they won't be showing up anytime soon -- the power consumption of such transistors is far beyond their electronic counterparts due to the energy inefficient lasers that power them.
Optical 'diode' lends hope to photonic computing, rayguns
The trouble with pesky Photon, at least as far as ultra-fast optical computing is concerned, is that he keeps coming back. If a data-carrying beam of light collides with reflections bouncing around between the components of a chip, it can suffer enough interference to make people yearn for the good old days of electrons. What's needed is the optical equivalent of a diode, which only allows light to pass one way, and that's exactly what researchers at Caltech and the University of California claim to have developed. As you'll see in the photo after the break, their metallic-silicon optical waveguide allows light to travel smoothly from left to right, but it breaks up and dissipates any photons traveling in the opposite direction. This is all good, because there's no point having futuristic 50Gbps optical interconnects if our CPUs lag behind. Light up the source link for a fuller explanation.
