Defense Advanced Research Projects AgencyTagged Content List

Photonics, Optics and Lasers

Science and technology dealing with the transmission and manipulation of light

Showing 13 results for Photonics + Integration RSS
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.
Only a few decades ago, finding a particular channel on the radio or television meant dialing a knob by hand, making small tweaks and adjustments to hone in on the right signal. Of course, we now take such fine tuning for granted, simply pressing a button to achieve the same effect. This convenience is enabled by radio frequency synthesis, the generation of accurate signal frequencies from a single reference oscillator.
Parallelism – or the act of several processors simultaneously executing on an application or computation – has been increasingly embraced by the microelectronics industry as a way of sustaining demand for increased system performance. Today, parallel computing architectures have become pervasive across all application domains and system scales – from multicore processing units in consumer devices to high-performance computing in DoD systems.