Photonic excess noise and wave localization

Abstract

This is a theory for the effect of localization on the super-Poissonian noise of radiation propagating through an absorbing disordered waveguide. Localization suppresses both the mean photon current $\ifmmode \bar{I}\else \={I}\fi{}$ and the noise power P, but the Fano factor $P/\ifmmode \bar{I}\else \={I}\fi{}$ is found to remain unaffected. For strong absorption the Fano factor has the universal value $1+\frac{3}{2}f$ (with f the Bose-Einstein function), regardless of whether the waveguide is long or short compared to the localization length.