IBM Details Superfast Optical Chipset
April 2, 2007 Timothy Prickett Morgan
The future of computing is, for many reasons, probably going to be optical because of the blazing speed and high bandwidth of optical circuits compared to electronic components. The U.S. Defense Department, which helped fund some advanced research by IBM certainly believes so, and both are pleased about a prototype optical chipset that Big Blue detailed at the 2007 Optical Fiber Conference in Anaheim, California, last week. Getting electronic signals off of chips and into networks requires a lot of energy, and it takes considerably more energy to move electrons, the basic unit of electricity, than it does to move photons, the unit of energy that makes up light. This is why telephone companies a long time ago moved to fiber optic cables and some day, if we are all lucky, we’ll have fiber optic links coming right into our homes, giving us a huge increase in bandwidth. The advances that researchers from IBM’s T.J. Watson Research Center detailed last week will allow fiber optic networks to link more smoothly into electronic components like processors and digital signal processors. The innovation with the prototype optical chipset that IBM is showing off comes from creating an optical transceiver (with both signal driver and receiver circuits) using the current CMOS technologies that IBM uses to make its Power and PowerPC chips. To this, IBM adds other optical components using indium phosphide and gallium arsenide circuits, which are more efficient than silicon circuits but which are more expensive to produce given the exotic nature of the materials. The whole chipset measures only 3.25 by 5.25 millimeters, and it can deliver an astounding 160 Gigabits per second. That’s eight times the bandwidth of experimental optical chipsets created by IBM. To put that into a human perspective, IBM says that this increase in bandwidth is enough to allow a high definition, feature-length file to download in a second instead of the 30 minutes it can take today on what are characterized as high-speed networks. IBM says that the compactness of the chipset design, the number of communication channels (in this case, 16), and the bandwidth in each channel is the highest that anyone has ever shown with optical circuits to date. IBM does not expect commercial applications of the optical chipset much before 2010, but has hinted that it could be used in its servers as well as in switches and routers.
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