Photonics, Optics and Lasers

Microelectromechanical systems, known as MEMS, are ubiquitous in modern military systems such as gyroscopes for navigation, tiny microphones for lightweight radios, and medical biosensors for assessing the wounded. Such applications benefit from the portability, low power, and low cost of MEMS devices. Although the use of MEMS sensors is now commonplace, they still operate many orders of magnitude below their theoretical performance limits. This is due to two obstacles: thermal fluctuations and random quantum fluctuations, a barrier known as the standard quantum limit.

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.

In the 1940s, researchers learned how to precisely control the frequency of microwaves, which enabled radio transmission to transition from relatively low-fidelity amplitude modulation (AM) to high-fidelity frequency modulation (FM). This accomplishment, called microwave frequency synthesis, brought about many advanced technologies now critical to the military, such as wireless communications, radar, electronic warfare, atomic sensors and precise timing.

The Direct On-Chip Digital Optical Synthesizer (DODOS) program seeks to create a technological revolution in optical frequency control analogous to the disruptive advances in microwave frequency control in the 1940s.

Free-space optics today requires a telescope, bulk lasers with mechanical beam-steering, detectors, and electronics. The Modular Optical Aperture Building Blocks (MOABB) program seeks to design all of these components into a single integrated device. In what would be deemed as the most complex electronic-photonic circuit ever fashioned, the program’s performers will work to create a wafer-scale system that is 100x smaller and lighter than conventional systems and can steer the optical beam 1,000x faster than mechanical components.