Jongmin Lee, Grant Biedermann, Hayden McGuinness, Daniel Soh, Justin Christensen, Roger Ding, Patrick S. Finnegan, Gregory A. Hoth, Will Kindel, Bethany Little, Randy R. Rosenthal, Joel R. Wendt, Tony Lentine, Matt Eichenfield, Michael Gehl, Ashok Kodigala, Aleem Siddiqui, Erik J. Skogen, Gregory A. Vawter, Aaron Ison, David Bossert, Kyle H. Fuerschbach, Daniel Paul Gillund, Charles A. Walker, Dennis J. De Smet, Connor Brashar, Joseph Berg, Prabodh M. Jhaveri, Tony G. Smith, Shanalyn A. Kemme, Peter Schwindt, Sandia National Laboratories

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Abstract:

We report the current progress in the development of a compact, deployable cold atom interferometry sensor platform towards atomic PNT (position navigation time) sensors. A simplified, reliable atomic sensor head with diffractive optics, alignment-free optical packages, and photonic integrated circuits (PIC) compatible laser architecture [1] are essential for its compactness and deployability. This cold atom sensor platform can be generally applied to gravimeters, accelerometers, gyroscopes, clocks and magnetometers, and the sensor platform includes significant engineering efforts of grating-mirror MOTs (magneto-optical trap), vibration immune mechanical structure design, custom titanium (Ti) vacuum package with passive pumping, silicon photonics multi-channel on-chip IQ modulators, and feedforward control with cosensors. We generated a rubidium grating-mirror MOT (GMOT) [2] with Sandia-fabricated grating chips and explored the atomic coherence of GMOT with Rabi oscillation and Ramsey interferometry. Sub-Doppler cooling process and high data rate measurement [3,4] were demonstrated in a custom Ti vacuum chamber. In addition, we performed atom interferometry experiments and measured gravity with Doppler-sensitive Raman beams with the PIC-compatible COTS (commercial off-the-shelf) photonic components such as IQ modulators, semiconductor optical amplifiers, and second harmonic generators, which minimizes optical channels and requisite components. In addition, there are significant efforts in the development of integrated photonics chips for the cold atom sensor platform with silicon photonics, III-V amplification, and second harmonic generation. We demonstrated silicon photonics four channel on-chip IQ modulators with a high extinction ratio and a high carrier-injection modulation [1], which can dynamically control laser frequencies and intensities during the experimental sequence of cold atom interferometers. Software-based modulator bias controller regulates the drift of cascaded dual-parallel Mach-Zehnder IQ modulators. We envision in a fully integrated system, which thirty on-chip IQ modulators can be applied to 6 degree of freedom (DOF) matterwave IMU (inertial measurement unit). The on-going efforts toward a compact, deployable cold atom interferometry sensor platform will enable matterwave inertial navigation sensors in a high dynamic environment and GPS-denied environments. References [1] A. Kodigala, M. Gehl, C. T. DeRose, D. Hood, A. T. Pomerene, C. Dallo, D. Trotter, P. Moore, A. L. Starbuck, J. Lee, G. Biedermann, and A. L. Lentine, CLEO 2019, pp. STh4N.6 (2019). [2] J. Lee, J. A Grover, L. A. Orozco, S. L. Rolston, J. Opt. Soc. Am. B Vol. 30, pp.2869 (2013). [3] Akash V. Rakholia, H. McGuinness, G. W. Biedermann, Phys. Rev. Applied 2, 054012 (2014). [4] H. McGuinness, A. V. Rakholia, G. W. Biedermann, Appl. Phys. Lett., 100, 011106 (2012). Acknowledgement This work is supported by the Laboratory Directed Research and Development program at Sandia National Laboratories, a multi-mission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525. This paper describes technical results and analysis. Any subjective views or opinions that might be expressed in the paper do not necessarily represent the view of the U.S. Department of Energy or the United States Government.