Laser stabilization to a cryogenic fiber ring resonator

The frequency stability of lasers is limited by thermal noise in state-of-the-art frequency references. Further improvement requires operation at cryogenic temperature. In this context, we investigate a fiber-based ring resonator. Our system exhibits a first-order temperature-insensitive point around 3.55 K , much lower than that of crystalline silicon. The observed low sensitivity with respect to vibrations ( < 5 ⋅ 10 − 11 m − 1 s 2 ), temperature ( − 22 ( 1 ) ⋅ 10 − 9 K − 2 ), and pressure changes ( 4.2 ( 2 ) ⋅ 10 − 11 m b a r − 2 ) makes our approach promising for future precision experiments.