École Nationale Supérieure de
Techniques Avancées

Résumé

Long-baseline interferometry is a powerful tool to achieve high-angular resolution observations. GRAVITY, an infrared interferometer at the Very Large Telescope Interferometer, allows for narrow-angle astrometry. In a context of improving its performances, we propose to study the non common path aberrations occurring within one of its sub systems: the Fiber Coupler. We measured the optical aberrations on each Off-Axis Parabola of the Fiber Coupler, as they affect the metrology of GRAVITY. To verify the performances of the Fiber Couplers, we replicated a prototype and conceived a phase-shifting interferometry method to measure the aberrations along the whole optical path of the Fiber Coupler. Our study provides insights in the mitigation of the impact of non-common path aberrations on GRAVITY’s performances and suggests ways to improve them.