The US Defence Advanced Research Projects Agency (DARPA) has announced the Robust Optical Clock Network (ROCkN) program to create optical atomic clocks to improve time synchronization. The program aims to develop practical, super-accurate optical atomic clocks with low size, weight, and power (SWaP) that yield timing accuracy and holdover better than GPS atomic clocks and can be used outside a laboratory.
ROCkN will leverage DARPA-funded research over the past couple of decades that has led to lab demonstration of the world’s most precise optical atomic clocks. ROCkN clocks will not be as precise as the best lab optical clocks, but they will surpass current state-of-the-art atomic clocks in both precision and holdover while maintaining low SWaP in a robust package.
The program will consist of two separate phases. The first phase will involve developing a robust, high-precision small portable optical clock that can fit on a fighter jet or satellite. The portable optical clock should be capable of providing picosecond (trillionth of a second) accuracy for 100 seconds. Also, it will need to withstand temperature, acceleration, and vibrational noise for use onboard aircraft, vehicles, or satellites.
The second phase will focus on building a larger but still transportable optical clock with unprecedented holdover performance. This clock should fit on a Navy ship or in a field tent to provide GPS-equivalent, nanosecond precision for 30 days in the absence of GPS.
ROCkN is a four-year program consisting of two two-year phases. At the end of the program, synchronization between stationary, mobile, and airborne clocks will be demonstrated with timing precision sufficient for 100 GHz distributed coherence.
“The goal is to transition optical atomic clocks from elaborate laboratory configurations to small and robust versions that can operate outside the lab,” said Tatjana Curcic, program manager in DARPA’s Defense Sciences Office. “If we’re successful, these optical clocks would provide a 100x increase in precision, or decrease in timing error, over existing microwave atomic clocks, and demonstrate improved holdover of nanosecond timing precision from a few hours to a month. This program could create many of the critical technologies, components, and demonstrations leading to a potential future networked clock architecture.”