Photonics, Optics and Lasers

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.

High-energy lasers (HEL) have the potential to benefit a variety of military missions, particularly as weapons or as high-bandwidth communications devices. However, the massive size, weight and power requirements (SWaP) of legacy laser systems limit their use on many military platforms. Even if SWaP limitations can be overcome, turbulence manifested as density fluctuations in the atmosphere increase laser beam size at the target, further limiting laser target irradiance and effectiveness over long distances.

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.

Find a way to replace a large, heavy and expensive technology with an equivalent one that’s a lot smaller, lighter and cheaper and you have a shot at turning a boutique technology into a world changer. Think of the room-sized computers of the 1940s that now are outpowered by the run-of-the-mill central processing unit in laptop computers. Or the miniaturized GPS components that contribute geolocation smartness in cell phones. DARPA program manager Joshua Conway has another shrinking act in mind: packing the light-catching powers of bulky lens-filled telescopes onto flat, semiconductor wafers that are saucer-sized or smaller, featherweight and cheap to make.

The Defense Advanced Research Projects Agency (DARPA) Microsystems Technology Office (MTO) is hosting a Proposers Day to provide information to potential proposers on the objectives that will be specified in an anticipated Broad Agency Announcement (BAA) of the Modular Optical Apertures Building Blocks (MOABB) program. The MOAB program aims to develop advanced technologies that could catalyze the creation of ultracompact light detection and ranging (LIDAR) systems.