In this thesis a reliable and robust single atom detector is presented, characterised and applied to measure the fluorescence emission of single atoms. The detector consists of a tapered single mode excitation fibre and a multi mode detection fibre, both integrated on an atom chip. Single neutral 87Rb atoms propagating freely in a 1D magnetic guide can be detected with an efficiency of 66% due to highly selective excitation and matched detection region. The detector allows to identify the statistical distribution of the atoms, which, for the current experiments, was proven to be Poissonian. Non-classical correlations in the photon emission from a single atom have been measured, showing a perfect photon anti-bunching. Rabi oscillations of the correlation function have been observed and proven to be in excellent agreement with theoretical expectations. The detector presented here is conceptionally much simpler than comparable integrated detectors employing cavity assisted detection and can be produced by using only commercially available lithographic techniques. With this detector single atom sensitivity is reached without the need for cavity assisted detection or localization of the atoms