Unveiling delay-time-resolved phase noise dynamics of narrow-linewidth laser via coherent optical time domain reflectometry

Abstract

Laser with high spectral purity plays a crucial role in high-precision optical metrology and coherent communication. Thanks to the rapid development of laser frequency stabilization, the laser phase noise can be remarkably compensated, allowing its ultra-narrow linewidth subject to mostly quantum limit. Nevertheless, the accurate characterization of phase noise dynamics and its intrinsic linewidth of a highly coherent laser remains ambiguous and challenging. Here, we present an approach capable of revealing delay-time-resolved phase noise dynamics of a coherent laser based on coherent optical time domain reflectometry (COTDR), in which distributed Rayleigh scattering along a delay fibre essentially allows a time-of-flight mapping of a heterodyne beating signal associated with delay-time-dependent phase information from a single laser source. Ultimately, this novel technique facilitates a precise measurement of ultra-narrow laser linewidth by exploiting its delay-time-resolved phase jitter statistics, confirmed with the analytical modelling and numerical simulations.

References in corpus (8)

• A sub-40 mHz linewidth laser based on a silicon single-crystal optical cavity
• 1.5 $\mu$m lasers with sub 10 mHz linewidth
• Integrated Waveguide Brillouin Laser
• Sub-Hz Linewidth Photonic-Integrated Brillouin Laser
• Experimenting an optical second with strontium lattice clocks
• Ultra low frequency noise laser by locking to an optical fiber delay line
• Observing the intrinsic linewidth of a quantum-cascade laser: beyond the Schawlow-Townes limit
• Quantum cascade laser frequency stabilisation at the sub-Hz level