A Versatile Testbed for CubeSat Atomic Clock Development: EOM vs Laser Current Modulation

Zachary Warren, Michael Huang, Hunter Kettering, Andrew Stapleton, James Camparo

Abstract:	Atomic clock applications for CubeSat missions require low size, weight, and power (SWaP), while maintaining high stability and accuracy. This puts “large” microwave cavity clocks at a disadvantage, and encourages all-optical schemes of clock signal generation such as coherent population trapping (CPT). Two alternatives for optical pumping in compact atomic clocks are 1) electro-optic modulation (EOM) or 2) injection-current modulation (ICM) of the pump laser. CPT contrast and signal-to-noise ratio (SNR) are both influenced by the efficiency of sideband generation and suppression of the carrier frequency, which can vary between EOM and ICM methods. Light shift effects in CPT are also increased by asymmetry in the sideband intensities, a feature of ICM that can impair clock performance. The testbed we are developing enables reconfiguration of components in order to quantify compact-clock signal generation techniques and sensitivities, and their effects on CPT. This paper describes preliminary results from our testbed analysis of the EOM-based and ICM-based optical sideband generation schemes for compact CubeSat clocks.
Published in:	Proceedings of the 49th Annual Precise Time and Time Interval Systems and Applications Meeting January 29 - 1, 2018 Hyatt Regency Reston Reston, Virginia
Pages:	100 - 106
Cite this article:	Warren, Zachary, Huang, Michael, Kettering, Hunter, Stapleton, Andrew, Camparo, James, "A Versatile Testbed for CubeSat Atomic Clock Development: EOM vs Laser Current Modulation," Proceedings of the 49th Annual Precise Time and Time Interval Systems and Applications Meeting, Reston, Virginia, January 2018, pp. 100-106. https://doi.org/10.33012/2018.15610
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