  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.
