March 18, 2008, Yorktown Heights, NY--IBM scientists took another significant advance towards sending information inside a computer chip by using light pulses instead of electrons by building the world's tiniest nanophotonic switch with a footprint about 100X smaller than the cross section of a human hair.
The switch is an important building block to control the flow of information inside future chips and can significantly speed up the chip performance while using much less energy. "This new development is a critical addition in the quest to build an on-chip optical network," said Yurii Vlasov, manager of silicon nanophotonics at IBM's TJ Watson Research Center. "In view of all the progress that this field has seen for the last few years it looks that our vision for on-chip optical networks is becoming more and more realistic."
Once the electrical signals have been converted into pulses of light, this switching device performs the key role of "directing traffic" within the network, ensuring that optical messages from one processor core can efficiently get to any of the other cores on the chip. The IBM team demonstrated that their switch has several critical characteristics which make it ideally suited to on-chip applications. First, the switch is extremely compact. Second, the device is able to route a huge amount of data since many different wavelengths or "colors" of light can be switched simultaneously. With each wavelength carrying data at up to 40 Gb/s, it is possible to switch an aggregate bandwidth exceeding 1 Tb/s--a requirement for routing large messages between distant cores. Last but not least, IBM scientists showed for the first time that their optical switch is capable of operating within a realistic on-chip environment, where the temperature of the chip itself can change dramatically in the vicinity of "hot-spots," which move around depending upon the way the processors are functioning at any given moment. The IBM scientists believe this temperature-drift tolerant operation to be one of the most critical requirements for on-chip optical networks.
Additional information on this development as well as on the IBM's nanophotonics project can be found at www.research.ibm.com/photonics.