IBM has devised an optical switch that it says could one day allow processor cores to exchange large files rapidly, the company plans to announce Monday.
The component, which is still in the experimental stage, is the latest piece of technology in the field of optoelecronics. Currently, signals inside chips gets passed on electrons running on microscopic wires. Compared with photons (particles of light), electrons are slow, and they generate heat. In optoelectronics, researchers hope to take technology from fiber-optic communication and shrink it to the chip level. Ideally, these miniaturized components can be produced inexpensively on silicon, increase computing performance, and reduce power consumption. IBM estimates that a chip connected with optical technology rather than wires would use a tenth of the power and 100 times more data could be shuttled between the cores per second than with today's chips.
The switch essentially directs data traffic between cores. The component can handle multiple wavelengths of light and has a potential aggregate bandwidth of one terabit per second, far more than what conventional input-output communication systems between chips can do today. Greater bandwidth would reduce latency between cores. It is also small enough to fit inside computers: 2,000 of them could fit into a square millimeter.
IBM also ran tests in harsh, high-temperature environments that simulate the inside of a functioning computer and it continued to work.
A number of companies--IBM, Intel, and start-ups like Primarion--have been experimenting with silicon lasers, waveguides, and other components for making optoelectronics a reality for about eight years. One of the coolest is a device that IBM came up with to slow down light to make it easier to encode with data. These components, however, won't show up in computers for at least a few more years.
IBM has come up with a technology that could one day let different cores on a processor exchange signals with pulses of light, rather than electrons, a change that could lead to faster and far more energy efficient chips.
The device, known as a silicon Mach-Zehnder electro-optic modulator--converts electrical signals into pulses of light. The trick is that IBM's modulator is 100 or more times smaller than other small modulators produced by other labs. Eventually, IBM hopes the modulator could be integrated into chips.
Electrons in, photons out.
(Credit: IBM)Here's how it works. Electric pulses, the yellow dots, hit the modulator, which is also being hit with a constant beam of light from a laser. The modulator emits light pulses to correspond to the electrical pulses. In a sense, the modulator is substituting photons for electrons.
Since the beginning of the decade, several companies--Intel, Primarion, Luxtera, IBM--have been coming up with components that, ideally, will let chip designers replace wires in computers and ultimately chips with optical fiber. Wires radiate heat, a big problem, and the signals don't travel as fast as light pulses. (The research in this area is known as silicon photonics and optoelectronics.)
The problem with optical technology, however, is making it small. Optical components historically have been tricky to produce and tend to be fairly large. Computer makers need components that measure only a few millimeters on a side. The idea is to come up with a way to produce modulators, lasers, waveguides and other devices on silicon manufacturing lines.
Right now, it remains an open question when these products will come to market. Still, the plethora of prototypes is a strong indication that progress is moving along well.
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