Dr. Joe Campbell and his students have developed high-speed detectors for optical signals. The integration of these building blocks is illustrated in Figure 2. This and other research has resulted in the development of optical devices that send and receive tiny laser beams. The laser's beam travels down waveguides and through various holographic elements that perform like small and precise mirrors, lenses and prisms. This layer, as indicated in Figure 2, can be added to the traditional multilayered circuit board from which a network of waveguides and holographic elements can be crafted.
Light signals travel in both directions throughout the network.
Fanning out the laser beam is the holographic grating coupler. It provides an optical connection port between light traveling within a waveguide and the device that requires the signal. As an example of the application of this research, the Optical Interconnects Group has been working on a circuit board for the Cray T-90, one of the world's most powerful supercomputers. The speed of the T-90 has begun to push the limits of the ability of its electronic circuits to transmit and receive crisp and clean timing signals across the circuit board. For proper operation of the computer, all signals must reach all the separate devices at the same time.