Nonclassical number-phase correlation in semiconductor lasers

Summary form only given. Optical phase is conjugate to the photon-number in quantum optics and therefore is important for nonclassical states in which the photon-number operator is reduced below the semiclassical shot noise limit, i.e., for photon-number squeezed states. Nonclassical emission from semiconductor lasers has the added facet that excess phase fluctuations are correlated with fluctuations in the photon-number through the nonlinear gain, and this correlation extends below shot noise. In this experiment, quantum-limited number-phase correlations are examined using an external-cavity semiconductor laser with heavily suppressed (>40 dB) side modes and near ideal single-mode laser characteristics. A feedforward gain matching condition is found to limit the observation of a strong nonclassical effect.