Complete characterization of supercontinuum coherence properties

Supercontinuum (SC) generated in highly nonlinear fibers exhibit unique spectral, temporal and spatial coherence [1] which impacts directly the intended application. It is therefore important to be able to evaluate the coherence properties of SC light in a systematic way. The first attempt to describe the coherence of SC pulses was reported by Dudley and Coen who have introduced the modulus of a normalized second-order coherence function averaged over a finite bandwidth [2]. Here, we reconsider the shot-to-shot fluctuations of SC by using standard two-time and two-frequency correlation functions of second-order coherence theory of non-stationary light. This allows us to (i) explicitly define unambiguous measures of temporal and spectral coherence and (ii) show that SC light can be decomposed into a sum of quasi-coherent and quasi-stationary contributions.