SAN FRANCISCOIntel Corp. is studying optical interconnects with an eye toward replacing chip-to-chip electrical interconnects in order to overcome looming bandwidth issues as microprocessors with an increasing number of cores usher in the era of tera-scale computing.
Ian Young, an Intel Fellow and director of the No. 1 semiconductor company's advanced circuits and technology integration project, presented a paper at the IEEE's International Solid State Circuits Conference (ISSCC) here Wednesday (Feb. 11) describing progress in integrating the waveguides, detectors and modulators needed for integrating photonic interconnects directly onto CMOS chips.
Intel Corp. Fellow
Young described the performance of an eight-channel, 90-nm device that has demonstrated transmission and reception speed of up to 10Gb/s. The company's longer-term goal is to make optical components that can achieve higher bandwidth of between 100GB/s to 1 TB/s, Young said.
Sending information via photons as opposed to electrons offers inherent advantages in terms of higher speed and lower power consumption. But monolithic integration of the required photonic and electro-optic components within CMOS chips presents a host of challenges.
In his presentation to the ISSCC Monday, Mark Bohr, Intel senior Fellow and director of process architecture and integration, described interconnect as one of the five major challenges facing IC scaling to the 32-nm node and beyond. Bohr said optical interconnects could be the solution "if technologies can be developed that cost effectively integrate photonics with silicon logic."
A recent panel of experts at the Photonics West show in San Jose, Calif. acknowledged that the computer industry wants optical interconnects in its future multicore processors, but agreed that there is no clear light source to drive on-chip optics and said the technology needs to get to significantly lower heat, power and cost to be viable.
Light has been used to transmit data for decades. In telecommunications, fiber optic systems have been in use since the 1970s. Photonic technology is also used in computer networks and is increasingly displacing electronic transmission for shorter and shorter distance communications.
For Intel's prototype chip, a microprocessor, the photonics are placed on top of the CMOS die, which does not compromise the performance of the device's transistors, Young said. "Because we are on top of the die, it's easy to get light on and off the chip," Young said.