Semiconductor laser stabilized by a photonic integrated 4 meter coil-waveguide resonator

We stabilize a semiconductor laser to a photonic-integrated, Si
³
N
4
, 4 meter coil resonator, achieving thermorefractive-noise-limited frequency noise. The laser exhibits a record low
$87\ \text{Hz}\ 1/\pi$
and 2.1 kHz
$\beta$
-separation integral linewidth and
$2.6\times 10^{-13}$
fractional frequency stability. © 2022 The Author(s)