Abstract : This thesis is devoted to the study of current correlation of single-electron beams in a ballistic quantum conductor. A mesoscopic capacitor is used as an on-demand single electron emitter to emit single charges in a quantum Hall effect edge channel. When driven by a large high-frequency excitation voltage, the source periodically emits a single electron followed by a single hole, thus generating a quantized AC current in units of 2ef_0, where f_0 is the drive frequency. We have measured the autocorrelation of the current fluctuations emitted by the source, putting into light a fundamental high-frequency noise limit, called quantum jitter, which is the signature of single particle emission. The measurements are in excellent agreement with both a heuristic model describing the mesoscopic capacitor as a perfect emitter, and more sophisticated time-dependent scattering model. We have also measured the autocorrelation of the current fluctuations after partition by a quantum point contact acting as an electronic beam-splitter. This geometry is the electronic analog of the quantum optics Hanbury-Brown and Twiss experiment, allowing to characterize the accuracy of single-particle emission. In a ballistic conductor, this geometry furthermore allows to measure the number of excitations generated per cycle, as well as to measure their energy distribution. These two experiments are the first realizations of single-charge electron quantum optics experiments, paving the way to more complex experiments such as two-particle collisions and single charge tomography.