Light and the Future of Computing

February 1928. A professor of physics at Calcutta University discovers that when light traverses a transparent material, some of the light that is deflected changes in wavelength. The prof is Dr. Chandrasekhara Venkata Raman. And his discovery, the Nobel Prize winning Raman Effect.

February 2005. Semiconductor giant, Intel announces that it has successfully deployed an all-silicon laser using the Raman Effect to carry data over light waves. Computing at the speed of light? Nay, more…

The Next Big Thing. Yes, four to five years from now, your PC could well be harnessing light instead of electrical currents to shuttle your bits and bytes to and fro. Apart from a leap-frogging computing speeds, the implication of this marrying of silicon chip technology with optical lasers, is that it could also lead to a drastic cut in costs for high-speed, high-bandwidth telecommunication systems, medical devices and defence equipment.

Behind Intel's Silicon Raman Laser breakthrough lies photonics. Photonics (derived from photon, a fundamental information carrier) is the science of generating, controlling, and using light to carry information. The advantage of carrying data over photons, or light, on optical fibre is that these generate less heat than electrons, the signal carriers on copper wire. And heat dissipation is one of the foremost problems that chip designers face. Since optical fibre can transmit greater volumes of data, it also means a reduction in cabling and the internal volume of computers. However, traditional optical components require exotic materials like indium phosphide and gallium arsenide, are difficult to manufacture and assemble, and consequently expensive. The cost limits the use of these photonic devices to special applications like long-haul telecommunications.

Intel's remarkable achievement is that it has miniaturised the Raman Effect so that it can be produced within a silicon chip, instead of employing costly optical components and bulky lasers. Intel has created a standard volume CMOS silicon chip containing eight continuous Raman lasers by using fairly standard silicon processes, rather than expensive materials and processes required for making lasers today. The lasers emit a continuous stream of light that can be modulated into a stream of impulses to represent data.

Thanks to our good Doc, the best in computing is yet to come…