IBM has announced that its researchers have built a device capable of delaying the flow of light on a silicon chip, which could lead the further development of using light instead of electricity to transfer data. Researchers have known that the use of optical instead of electrical signals for transferring data within a computer chip might result in significant performance enhancements since light signals can carry more information faster. The engineering challenge is buffering data on the chip, which is difficult given light's speed. Thus, a means of using light effectively is to delay its travel.

Long delays can be achieved by passing light through optical fibers. IBM scientists were able to delay light by passing it through a new form of silicon-based optical delay line built of up to 100 cascaded "micro-ring resonators," built using current silicon complementary metal-oxide-semiconductor (CMOS) fabrication tools. When the optical waveguide is curved to form a ring, light is forced to circle multiple times, delaying its travel. The optical buffer device based on this simple concept can briefly store 10 bits of optical information within an area of 0.03 square millimeters. This advancement could potentially lead to integrating hundreds of these devices on one computer chip, an important step towards on-chip optical communications.