"This fellowship proposal aims at the development of Dr. Bruno Chazelas's young career in the direction of instrumentation in astrophysics. The fellow, has a background in optical instrumentation applied to astrophysics. The objectives of this project are to expand his experience in new instrumentation domains, to develop his research background in astrophysics, and to acquire the experience of practical astronomical observation. The research experience of the applicant, was centered on the direct detection and spectroscopy of the atmosphere of extra-solar planets via nulling interferometry (DARWIN, ESA mission). The subject of this project is to make decisive technological advances in the radial velocity detection technique (most productive current detection method) that will permit to discover the firsts earth-like planets. The applicant will work on these subjects at the Geneva Observatory, a top level research group in extra-solar planet detection and characterization. This team thanks to its access to the most advanced radial velocities instruments (CORALIE, HARPS) and their large experience in that field will offer the applicant a perfect environment to develop his competencies. The fellow will also participate to the ongoing research programs via his observational work. Two of the known limiting factors of the current radial velocity instruments are the calibration and the light feeding into the spectrometer. These two issues will be addressed during this project, in order to obtain the required 10 cm.s¯¹ precision that is needed to detect earth like planets (1 earth mass in the habitable zone i.e., 1 au for a sun-like star). In order to enlarge the fellow experience in instrumentation he will participate to the PRIMA astrometric instrument commissioning and to some of the following observational programs dedicated at the search and characterization of extra-solar planets."