DODOS: Direct On-Chip Digital Optical Synthesizer

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. 

That early development ushered in a new era for microwave technology, transformed modern warfare, and has since been enabling a multitude of Department of Defense (DoD) and civilian capabilities, including radar, navigation technologies, and satellite and terrestrial communications. 

Extending frequency control to the optical regime is anticipated to greatly extend the technology base for the next generation of warfighter and other capabilities.

Since the first demonstration of optical frequency synthesis using self-referenced optical combs in 2000, demonstrations of novel civilian and defense applications for the technology have emerged worldwide. Due to the large size, relative fragility, and high cost of these components and systems, however, precise optical frequency synthesis has been limited to lab-scale experiments. 

DODOS aims to leverage recent breakthroughs in chip-scale mode-locked lasers and microresonators to enable self-referenced optical frequency combs in compact integrated packages. The program proposes to draw on recent progress in heterogeneous photonic integration to arrange all of the necessary components, including widely tunable laser sources, optical modulators, non-linear photonic elements, and CMOS radiofrequency (RF) and control circuitry onto a chip with a volume of less than 1 cm^3 and power consumption of less than 1 Watt. 

The DODOS chip will act as a gearbox to directly translate the stability and accuracy of an RF signal to the optical domain, producing laser light at frequencies above 200 terahertz with relative accuracy of one part in 10^15.

New generations of optical frequency control technology could enable a wide range of applications in optical spectroscopy, gas sensing, LiDAR, portable atomic clocks, high-bandwidth and secure communications, and intrusion detection, among other areas. 

The DODOS program also aims to spur research in octave-spanning microcombs, high-efficiency chip-scale lasers, high-efficiency on-chip frequency doubling, and CMOS-compatible integration technology.