Microchips and Components

Long coils of optical waveguides—any structure that can guide light, like conventional optical fiber—can be used to create a time delay in the transmission of light. Such photonic delays are useful in military application ranging from small navigation sensors to wideband phased array radar and communication antennas. Although optical fiber has extremely low signal loss, an advantage that enables the backbone of the global Internet, it is limited in certain photonic delay applications. Connecting fiber optics with microchip-scale photonic systems requires sensitive, labor-intensive assembly and a system with a large number of connections suffers from signal loss.

DARPA-funded researchers have developed one of the world’s largest and most complex computer chips ever produced—one whose architecture is inspired by the neuronal structure of the brain and requires only a fraction of the electrical power of conventional chips.

Many essential military capabilities—including autonomous navigation, chemical-biological sensing, precision targeting and communications—increasingly rely upon laser-scanning technologies such as LIDAR (think radar that uses light instead of radio waves). These technologies provide amazing high-resolution information at long ranges but have a common Achilles heel: They require mechanical assemblies to sweep the laser back and forth. These large, slow opto-mechanical systems are both temperature- and impact-sensitive and often cost tens of thousands of dollars each—all factors that limit widespread adoption of current technologies for military and commercial use.

By combining complementary mindsets on the leading edges of electronic and radiofrequency device engineering, a pair of researchers in DARPA’s Young Faculty Award program have devised ultratiny, electronic switches that approximate inter-neuron communication. These highly adaptable nanoscale switches can toggle on and off so fast, and with such low loss, they could become the basis of not only computer and memory devices but also multi-function radiofrequency (RF) chips, which users might reprogram on the fly to behave first like a cell-phone’s signal emitter but then, say, as a collision-avoidance radar component or a local radio jammer.

Solid-state electronics began to overtake vacuum tubes in radios, computers and other electronic and radio frequency gadgetry more than 60 years ago. Now we live in a Silicon Age. Even so, vacuum electronic devices, whose origins date to the 19th century, touch our lives every day.