Palm-sized, vibration-insensitive, and vacuum-free all-fiber-photonic module for 10<sup>-14</sup>-level stabilization of CW lasers and frequency combs

Abstract

Compact and robust frequency-stabilized laser sources are critical for a variety of fields that require stable frequency standards, including field spectroscopy, radio astronomy, microwave generation, and geophysical monitoring. In this work, we applied a simple and compact fiber ring-resonator configuration that can stabilize both a continuous-wave laser and a self-referenced optical frequency comb to a vibration-insensitive optical fiber delay-line. We could achieve a thermal-noise-limited frequency noise level in the 10 Hz-1 kHz offset frequency range for both the continuous-wave laser and the optical frequency comb with the minimal frequency instability of 2.7 x 10(-14) at 0.03-s and 2.6 x 10(-14) at 0.01-s averaging time, respectively, under non-vacuum conditions. The optical fiber spool, working as a delay reference, is designed to be insensitive to external vibrations, with a vibration sensitivity of sub-10(-10) (1/g) and a volume of 32 ml. Finally, the ring-resonator setup is packaged in a palm-sized aluminum case with 171-ml volume with a vibration-insensitive spool, as well as an even smaller 97-ml-volume case with an ultracompact 9-ml miniaturized fiber spool.