Theory of natural fluctuations of the intensity and frequency of radiation from multimode injection lasers

Analytic expressions are derived for the spectral densities of fluctuations of the intensities and frequencies of individual modes, and also of fluctuations of the total radiation intensity of a multimode injection laser. Graphs are plotted for ten lasing modes and typical values of the laser parameters. It is shown that some features of the spectra due to multimoding are most clearly observed in the absence of a correlation between the sources of fluctuation of the individual modes.