Semiclassical dynamics of excess quantum noise - art. no. 043801

A semiclassical theoretical framework is presented to describe the essentia l features of the excess quantum noise that occurs in systems with nonortho gonal eigenmodes. Excess noise is shown to be always spectrally colored, in stead of white, so that the Petermann excess noise factor is best written a s K(w) instead of K. The consequences of this spectral coloring are analyze d for lasers, both below and above the lasing threshold.