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Next-generation optical atomic clocks and quantum sensors are currently being investigated for positioning, navigation, and timing (PNT) applications such as navigation in GPS-denied environments and multi-static synthetic aperture radar (SAR) as well as commercial applications in 5G-and-beyond wireless communication, satellite synchronization, and geodetic sensing. These sensors have optical, electrical, and mechanical requirements for field deployability that are more challenging than those of prior industrial laser developments. These challenges can include broad optical spectral coverage and/or challenging narrow linewidth requirements of laser sources, low-noise laser driver and feedback electronics, high-bandwidth microwave detection and generation, thermal management and precision temperature control, and environmental ruggedness including passive and active vibration suppression. The laser systems used in current experiments require unacceptably large size, weight, and power designs and are sensitive to thermal and acoustic fluctuations. In this effort, we focus on an optical clockwork that will facilitate both civilian and military applications on a path to eventual deployment in GPS-denied environments. Two key optical subsystems necessary for next-generation field-deployed timekeepers include optical frequency combs (OFCs) and ultranarrow linewidth (UNL) lasers that are suitable for the interrogation of ultranarrow clock transitions. Vescent has developed a radiation-hardened-by-design optical frequency comb and is miniaturizing and ruggedizing these comb systems to eventually be deployed on satellites. The Technology Readiness Level of these OFCs has been tested at level 6 without any appreciable performance degradation and will be discussed. A summary of how OFC and UNL systems can be integrated into potential optical atomic clock systems will be presented.
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