Effect of mode-partition noise on intensity squeezing in a two-mode laser

For a general class of two-mode lasers, simple analytic expressions are derived for the magnitude of, and the correlation between, the intensity fluctuations in the two modes. The mode-partition fluctuations and overall intensity dynamics are demonstrated to be almost decoupled, so that the former can be treated as a small perturbation to the standard description of intensity squeezing in a single-mode laser. An example is formed by polarization partition noise in vertical-cavity surface-emitting lasers (VCSELs). Mode-partition noise in general, and polarization fluctuations in VCSELs in particular, are thus predicted to have only a limited deteriorating effect on the attainable intensity squeezing.