Quantum correlation between longitudinal-mode intensities in a multimode squeezed semiconductor laser.

Abstract

The intensity-noise properties of a constant-current-driven multimode semiconductor laser were studied theoretically and experimentally. It was shown that the total intensity noise of a pump-noise-suppressed multimode semiconductor laser was reduced to below the standard quantum limit even though the intensity noise of each individual mode had large excess intensity noise. This discovery stems from negative quantum correlations between longitudinal-mode intensities.