Sub-kHz lasing of a CaF_2 Whispering Gallery Mode Resonator Stabilized Fiber Ring Laser

TL;DR

This paper demonstrates a fiber ring laser stabilized by a calcium fluoride whispering-gallery-mode resonator, achieving sub-kHz linewidth and high frequency stability at 1530 nm, with potential applications in precision measurements.

Contribution

It introduces a novel stabilization technique using a CaF_2 whispering-gallery-mode resonator for fiber lasers, achieving linewidth below 650 Hz.

Findings

Linewidth below 650 Hz achieved

Frequency stability of 3.3 x 10^(-12) over 16 microseconds

Effective linewidth characterization using three-cornered hat method

Abstract

We utilize a high quality calcium fluoride whispering-gallery-mode resonator to stabilize a simple erbium doped fiber ring laser with an emission frequency of 196 THz (wavelenght 1530 nm) to a linewidth below 650 Hz. This corresponds to a relative stability of 3.3 x 10^(-12) over 16 \mus. In order to characterize the linewidth we use two identical self-built lasers and a commercial laser to determine the individual lasing linewidth via the three-cornered hat method.