Silicon photonics

Optical waveguides and silicon nanophotonics pave the way to energy-efficient supercomputers


The Photonics group is working in close cooperation with related IBM teams on several innovative projects aimed at integrating optics on chips. One project involves using silicon nanophotonics to integrate optical functionality into processors on the nanometer scale. First devices demonstrate the potential to achieve data transmission rates in the range of terabits per second. In the future, processors will be comprised of several layers: a logical layer of transistors, a storage layer and a layer of nanophotonic components that exploit the excellent optical conducting qualities of silicon. This technology is known as “CMOS integrated silicon nanophotonics”. The high integration density of optical and logical components in a 3-D design will increase the bandwidth density and improve the energy efficiency of these new chips significantly. Although such miniaturized optical components would be more costly to produce, this can potentially be compensated by using standard CMOS fabrication lines.

First prototypes of this technology are already functional in a laboratory setting, and could go into standard testing within the next ten years. Based on the current trend toward ever more powerful high-end computers, it is expected that supercomputers comprising nearly 100 million computation modules and featuring exaflop performance rates, i.e. one trillion (1018) operations per second, will be developed within that timeframe. Without improved energy efficiency on all levels, however, a future supercomputer would require its own dedicated power plant.

The Photonics research group will profit greatly from the Nanotechnology Center opened in the spring of 2011. The infrastructure is ideal for our prototype fabrication. The cutting-edge cleanroom facilities are a considerable improvement over the laboratory conditions available up to now. In the new facilities, we can perform the entire fabrication process. For the further development of optical transmission technologies, IBM has entered into several joint research projects with commercial partners. Moreover, for fundamental research in the field of silicon nanophotonics, IBM is collaborating with scientists from the Swiss Federal Institute of Technology in Zurich (ETHZ). This renowned university is IBM's partner and co-operator of the new Nanotechnology Center as part of a strategic joint venture in the nanosciences.