Coherent-mode representation of supercontinuum.

We apply the coherent-mode expansion to correlation functions used to describe the coherence properties of supercontinuum generated in nonlinear fibers. We show that the leading term of the expansion represents the quasi-coherent part of the field while the quasi-stationary part is embedded into the higher-order modes. The evolution of the modal expansion and the number of modes needed to describe the supercontinuum field are also discussed.

Second-order coherence of supercontinuum light.

We analyze the coherence properties of supercontinuum generated in photonic crystal fibers by applying the second-order coherence theory of nonstationary light. Using an ensemble of simulated realizations, we construct two-frequency cross-spectral density and two-time mutual coherence functions. This allows us to introduce measures of temporal and spectral coherence.

Distinguishing between deterministic and stochastic pulse broadening.

Two mechanisms can cause similar broadening of pulses in a pulse train: variable temporal/spectral phase in a train of identical pulses (a deterministic mechanism) and partial correlations between different frequency components of the pulses (a stochastic mechanism). We discuss methods to distinguish between these two fundamentally different mechanisms. We show that their roles can be separated, at least for an important class of fields known as Gaussian Schell-model pulses, using time-resolved intensity measurements of pulses passing through Michelson's interferometer.