Compact Plug and Play Optical Frequency Reference Device Based on Doppler-Free Spectroscopy of Rubidium Vapor

Abstract

Compactness, robustness and autonomy of optical frequency references are prerequisites for reliable operation in mobile systems, on ground as well as in space. We present a standalone plug and play optical frequency reference device based on frequency modulation spectroscopy of the D2-transition in rubidium at 780 nm. After a single button press the hand-sized laser module, based on the micro-integrated laser-optical bench described in [J. Opt. Soc. Am. B 38, 1885-1891 (2021)], works fully autonomous and generates 6 mW of frequency stabilized light with a relative frequency instability of 1.4×10 −12 at 1 s and below 10 −11 at 10 5 s averaging time. We describe the design of the device, investigate the thermal characteristics affecting the output frequency and demonstrate short-term frequency stability improvement by a Bayesian optimizer varying the modulation parameters.