This thesis is devoted to the study of optical parametric emission from resonantly excited semiconductor microcavities. These systems are formed by multiple quantum wells embedded in an optical microcavity. The parametric light they produce under resonant excitation shows interesting properties. We studied this emission both from one dimensional cavities, or photonic wires, and multiple coupled planar cavities. Using such structured samples we can observe parametric beams, signal and idler, perfectly intensity-balanced under normal incidence of the pump beam. These features are very interesting in view of possible future applications. We studied the properties of the parametric beams produced by one dimensional microcavities with a Hanbury Brown and Twiss interferometer. This setup allows us to measure the second order coherence properties of parametric emission. Specifically we measured the photon statistic of each parametric beam and their mutual correlations. The study of parametric emission in coupled microcavities evidenced a spontaneous symmetry-breaking and pattern formation in the optical parametric oscillation regime. We showed also different methods of optical control of these patterns, for example changing the direction of the pump linear polarization or adding a second beam, in a pump-probe experiment. This study points out a fundamental analogy between microcavity OPOs and macroscopic OPOs
