The use and extent of today's fiber optics networks is now self evident. Aside from the fiber itself, mastering the end-of-fiber compoments is a key issue in optimising those networks, whether it be from the emitter or receptor side. One of the major issues is the shaping pf ligt pulses, both spatially and temporally. spatial shaping requires the realisation of the optical systems at the interface between laser source and optical fiber. These components are often called micro-lenses. In the PHD work, we propose a novel model of the growth and optical properties of a new type of microlens, which we may call " optical micro-tip". It is grown out of the photopolymerisation of an organic material drop deposited on top of the cleaved fiber end. ...