Ultra-narrow Linewidth Lasers for Deployed Quantum Timing Applications

Vescent Photonics, LLC (Vescent) in collaboration with the Massachusetts Institute of Technology Lincoln Laboratory (MIT-LL) proposes to develop a compact ultra-narrow linewidth laser based on photonic integrated chip (PIC) technology for next-generation fieldable quantum sensor applications including optical atomic clocks, two-way time transfer, and precision inertial force and gravity sensing.nbsp; Atomic clocks represent the most precise and accurate instruments developed by scientists to date and enable applications including the measurement of weak gravitational fields in near-zero gravity as well as accurate positioning, navigation, and timing (PNT) onboard a spacecraft. However, high-performance optical atomic clocks, including Sr+ trapped-ion clocks, currently only exist in laboratory settings due to constraints on the size, weight, power, and cost (SWaP-C) and environmental susceptibility of critical technology subsystems. One of the key subsystems so far hindering the transition of these high-performance optical clocks outside the laboratory is the ultra-narrow-linewidth (lt; 100 Hz) laser required to interrogate the atoms. The solution proposed here for the development of an ultra-narrow linewidth laser is an extension to the initial demonstrations by Dr. William Loh at MIT-LL with fiber-based stimulated Brillouin scattering (SBS) lasers which have been demonstrated in an operating Sr+ trapped-ion clock, resulting in an ADEV of 3.9E-14/(Tau)^(0.5). Using these fiber-based results as a baseline, recent measurements conducted by the MIT-LL team have shown an evolution toward PIC-based waveguide cavities that can support ultranarrow-linewidth lasers via SBS. The effort proposed here seeks to integrate necessary chip-scale components to move towards a design where the entire ultra-narrow-linewidth laser system is contained on a chip-scale device.nbsp;