IBM builds world's smallest photonic switch

Stephen Withers
Tuesday, 18 March 2008 02:29

Your IT - Home IT

Scientists at IBM's TJ Watson Research Center have created a nanophotonic switch so small that 2000 of them could fit into an area as small as one square millimetre. The development has implications for future multicore processor designs.

Current technology connects multiple CPU cores with electrical currents flowing along copper wires. This approach is fine for small numbers of cores, but chip designers are looking beyond current two and four core processors to a future that may involve hundreds of cores. In such an arrangement, copper interconnections would consume too much power as well as being too slow.

On-chip optical connections could be 100 times faster yet use one-tenth as much power.

Apart from its small size, an advantage of IBM's design is that the device can switch multiple wavelengths simultaneously with an aggregate bandwidth of over 1Tbps.

Another important achievement is that not only has the switch has been shown to operate at temperatures experienced on processor chips, it also continues to work properly when the temperature fluctuates according to the work actually being done by a CPU.

The silicon-based switch is the latest in a series of IBM developments towards the creation of on-chip optical networks. Previous steps include the creation of an optical buffer and a tiny device to convert electrical signals into light.

"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 the 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."