The processor giants research labs are exploring ways to use silicon photonics—on-chip components that use light to transmit data—to replace electrical interconnects using copper wiring and simultaneously speed up vital connections that move data into and out of processors.
Intel thinks that electrical interconnects will continue to be used for some time to come, but that optical eventually will win out as it becomes more difficult to wring performance out of copper wires.
Creating bus that can move more data is vital to Intel as the chip maker moves deeper into the realm of multicore chips. Intel recently introduced dual-core Pentium desktop processors, which have two individual processor cores inside a single slice of silicon, where previous chips had only one.
It will begin rolling out dual-core notebook and server chips later this year. It follows that future generations of its processors will grow to have four, eight or more cores. Intel must come up with a data pipeline to meet those needs.
"The potential here is for silicon photonics to be used as the technology to underpin future optical busses" for multicore PC processors, said Manny Vara, a technology strategist at Intel Corp.s research and development labs.
When it comes to designing computers with a chip that sports a large number of cores, "the problem is feeding [the chip] … so its not sitting there doing nothing," Vara said. Not to mention, "once its done with the data, how do you get it out? How do you connect it with other components, because those are getting faster as well?"
Silicon photonics could be an ideal because of its potential to offer very high bandwidth—Intels already got gear running at 10 gigabits per second in its labs—and its ability to be designed directly into the chip itself, Vara said.
Others, including Startup Luxtera Inc., are also working on silicon photonics gear. Luxtera, which is working on a light modulator that works to convert light signals into data, hopes to build it into silicon next year. The company has been working with Freescale Semiconductor Inc.
But Intel believes it can do it all—manufacturing all of the necessary components, including lasers, in-house using its standard chip-manufacturing techniques. That result, aside from helping to lower costs, is the ability to add the connections directly to its own chips, thus creating desktop, notebook and server processors with optical busses built-in, Vara said.
Its working now to create prototype silicon photonics interconnects that can link racks of servers. Intel believes these rack-to-rack interconnects could appear first, within about three to five years.
Circuit board-to-circuit board connections would arrive next. Chip-to-chip connection would arrive last, likely in five years or more, somewhere in the 2010 or later time frame, according to documents published by Intel.