Today’s computer components are connected to each other using copper cables or traces on circuit boards. Due to the signal degradation that comes with using metals such as copper to transmit data, these cables have a limited maximum length. This limits the design of computers, forcing processors, memory and other components to be placed just inches from each other. Intel has announced an important breakthrough that could see light beams replace the use of electrons to carry data in and around computers, enabling data to move over much longer distances and at speeds many times faster than today’s copper technology.
The company has developed a research prototype it says represents the world’s first silicon-based optical data connection with integrated lasers. The link can move data at speeds of up to 50 gigabits per second – that’s the equivalent of an entire HD movie being transmitted each second. The achievement is another step toward replacing metal connections with extremely thin and light optical fibers that could radically change the way computers of the future are designed and alter the way the datacenter of tomorrow is built.
Future applications
Silicon photonics is expected to have applications across the computing industry. Intel says the data rates possible with the technology could enable wall-sized 3D displays for home entertainment and videoconferencing with resolutions so high that the actors or family members appear to be in the room with you. The company also imagines tomorrow’s datacenter or supercomputer may see components spread throughout a building or even an entire campus, communicating with each other at high speed, as opposed to being confined by heavy copper cables with limited capacity and reach. This will allow datacenter users, such as a search engine company, cloud computing provider or financial datacenter, to increase performance, capabilities and save significant costs in space and energy, or help scientists build more powerful supercomputers to solve the world's biggest problems.
50Gbps “concept vehicle”
While telecommunications and other applications already use lasers to transmit information, current technologies are too expensive and bulky to be used for PC applications.Justin Rattner, Intel chief technology officer and director of Intel Labs, demonstrated the Silicon Photonics Link at the Integrated Photonics Research conference in Monterey, Calif. The 50Gbps link is akin to a "concept vehicle" that allows Intel researchers to test new ideas and continue the company's quest to develop technologies that transmit data over optical fibers, using light beams from low cost and easy to make silicon, instead of costly and hard to make devices using exotic materials like gallium arsenide – a material used in the recent development of a device that can be used as an optical switch.
"This achievement of the world's first 50Gbps silicon photonics link with integrated hybrid silicon lasers marks a significant achievement in our long term vision of ‘siliconizing' photonics and bringing high bandwidth, low cost optical communications in and around future PCs, servers, and consumer devices" Rattner said.
Prototype components
The 50Gbps Silicon Photonics Link prototype is composed of a silicon transmitter and a receiver chip, each integrating all the necessary building blocks from previous Intel breakthroughs including the first Hybrid Silicon Laser co-developed with the University of California at Santa Barbara in 2006 as well as high-speed optical modulators and photodetectors announced in 2007.
The transmitter chip is composed of four such lasers, whose light beams each travel into an optical modulator that encodes data onto them at 12.5Gbps. The four beams are then combined and output to a single optical fiber for a total data rate of 50Gbps. At the other end of the link, the receiver chip separates the four optical beams and directs them into photo detectors, which convert data back into electrical signals.
Both chips are assembled using low-cost manufacturing techniques familiar to the semiconductor industry. Intel researchers are already working to increase the data rate by scaling the modulator speed as well as increase the number of lasers per chip, providing a path to future terabit/s optical links – rates fast enough to transfer a copy of the entire contents of a typical laptop in one second.
