Spectral Noise Correlations of an Ultrafast Frequency Comb

TL;DR

This paper introduces a method combining cavity-based noise detection and ultrafast pulse shaping to analyze spectral amplitude and phase noise correlations in an ultrafast frequency comb, revealing underlying noise modes.

Contribution

It presents a novel spectral correlation measurement technique and provides a complete description of comb dynamics through classical noise matrices and eigendecomposition.

Findings

Identified decoupled noise modes governing comb dynamics

Measured spectral noise correlations against the quantum limit

Deduced macroscopic noise properties from noise matrices

Abstract

Cavity-based noise detection schemes are combined with ultrafast pulse shaping as a means to diagnose the spectral correlations of both the amplitude and phase noise of an ultrafast frequency comb. The comb is divided into ten spectral regions, and the distribution of noise as well as the correlations between all pairs of spectral regions are measured against the quantum limit. These correlations are then represented in the form of classical noise matrices, which furnish a complete description of the underlying comb dynamics. Their eigendecomposition reveals a set of theoretically predicted, decoupled noise modes that govern the dynamics of the comb. Finally, the matrices contain the information necessary to deduce macroscopic noise properties of the comb.