IBM is among several companies betting big on optical computing as the next big thing to replace traditional electricity based computing. Optical computing is seen as a stepping stone for even more advanced computing technologies such as quantum computing.
In order to build a quantum computer, three key light-based components are needed: transistors to form a CPU, I/O equipment, and memory/storage media. IBM already has the I/O side well on the way, thanks to its advanced fiber optics research and switching breakthroughs. It has also seen great gains in memory and storage media. Finally, it could likely adapt its switching technology from the I/O research to form a transistor analog.
All the pieces are in place, though still in early stages, however; one critical component was missing -- something to make intense light pulses on a nanoscale. IBM needed a nanolaser and that's exactly what its researchers have created.
The new nanolaser will likely be analogous to the clock in a full nanocomputer, producing the driving impulses. Further nanolasers could convert electric signals from peripherals to laser impulses to be sent to the CPU. The system could also be used more modestly in a shrunk version of fiber optic network on traditional electric systems.
The breakthrough device utilizes a familiar friend -- the carbon nanotube. Carbon nanotubes, formed from interconnected hexagonal carbon rings, are also being studied as a material for traditional electric transistors, thanks to their great conduction, strength, and flexibility.
The new research, reported in the August 25 Nature Nanotechnology journal, uses a special nanotube-based field effect transistor to generate light impulses on a nanoscale. The light impulses are then routed by a pair of tiny nanocavity mirrors. By controlling the nanocavity mirrors, the wavelength of the optical emissions, the spectral and spatial distributions of the emitted light and the efficiency of the emissions could all be controlled.
An optical computer could theoretically perform computations at the speed of light (though only the speed of light in mediums such as glass, not the more commonly used speed of light in a vacuum). This would allow for faster computers. Also, the light impulses would likely generate less waste heat then electric circuits, which would allow for denser hardware.
A quantum computer could take these gains even farther, computing at faster than the speed of light, thanks to bizarre quantum effects such as entanglement. However, a quantum computer would require manipulation of single electrons, where an optical computer only would require larger light-controlling components.
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