A Precision and Integrated Microwave Kerr Frequency Comb, Stablilized to Strontium (Sr) Clock Oscillator

ABSTRACT: We propose to create a compact laser system suitable for a Sr lattice clock application. The system includes a diode laser stabilized to an ultrahigh-Q 698-nm microcavityto achieve 1x10-14 frequency instability at 1 second integration as well as generation of a Kerr frequency comb having the same frequency instability level. This advancement is based on state-of-the-art measurements and preliminary results by our team, enabled by the highest quality factor optical resonators measured to-date. Our program consists of two integrated tasks: (1) self-injection phase and frequency locking of a cavity-laser and noise cancellation beyond the thermal noise limit with ultrahigh-Q microcavities (cold microcavity Q>1010) and(2) second-stage stabilization through thermal division by the microcavity frequency comb for frequency instability better than 10-14 at 1 second. The comb will be centered at the 698-nm optical frequency suitable for the divalent Sr 1So-3Po clock transition interrogation. BENEFIT: The optical resonator developed in this Project will have far superior performance to any other advanced fieldable resonators with comparable size, power consumption, and cost. The examined 698-nm resonator is directly compatible with the long-term stable Sr1So-3Po clock transition, allowing the world"s best timing and frequency standard in a compact realization. We expect that this Project will result in a visible-frequency resonator clock and comb prototype that will be ready for transition to both military and civilian applications. The resonator will dramatically enhance the performance of a wide range of DOD systems, and civilian products. While the resonator has multiple applications, we will focus our efforts on its usage for compact all-optical atomic clocks, being of interest to DoD.