Setting of an adaptive optics system with partial correction at visible wavelenght

Adaptive optics are now installed on many giant telescopes around the<br />world, but they remain costly systems and time-consuming to implement.<br />Several years ago a project started to equip the interferometer GI2T of the<br />Calern Observatory (France) with an adaptive optics assuming partial correction<br />and working in the visible wavelenghts. The specifications led us to the<br />realization of a system of 31 sub-pupils with a sampling frequency of 2500Hz. To<br />respect our budget we developed a new curvature wavefront sensor far cheaper<br />than habitually used equipment.<br /><br />Preliminary studies were done for the choice of the various elements, and we<br />present in this thesis the tests of characterization. After the description and<br />characterization of the system we present the different steps of the tuning<br />of the system which brought about the working of our new wavefront sensor.<br /><br />The real-time calculator was inherited from a development made by ONERA and the<br />Shaktiware company. We have had to modify the controler to make it work<br />with 31 sub-pupils. We propose a study of the transfer function of our system<br />and the possible optimizations for the choice of the algorithms of control.<br /><br />Our adaptive optics is not limited to its use in the framework of the<br />GI2T interferometer and we completed a study and began its installation on the<br />Laser-Lune telescope of 1.5 meters in the Calern Observatory.<br /><br />The series of laboratory tests has shown the good working of our system,<br />but we haven't assessed the performances of the servo loop control at high<br />frequency. Simulations predict a Strehl ratio of 0.15 at 635nm for a<br />telescope of 1.5 meter in average conditions.