Micro atomic clock : development of an operating thermal model and experimental validation

This report deals with the development of a thermal model of the physical package of a micro atomic clock. Several fields of the daily life such as the GPS navigation system or telecommunication now depend on atomic clock. These clocks, based on the energy transition of the cesium atom 133, allow obtaining a very stable and accurate temporal signal. The physical package of an atomic clock is the part of the structure which contains the cesium gas and a laser (VCSEL in the case of an atomic clock). This laser allows questioning the cesium atoms. Nevertheless, the laser and the cesium gas temperatures have an influence on the clock stability. In order to obtain the most stable clock as possible, the temperatures of these two parts need to be as stable as possible. The internship purpose is to develop a thermal model of the physical package containing the laser (VCSEL) and the cesium gas. To develop this model, I have used the simulation software Simulink from Matlab. In order to have a model as accurate as possible, I have used the software COMSOL Multiphysics and experimental results. Those experimental results have been obtained after having implemented different experiments. The thermal model is operational and results are quite in line with experimental results for the steady state. For the dynamic regime, some improvements must be implemented in order to validate the model.