This work aims to studying the possible design of an all optical router compatible with intensities and wavelengths which are present in optical telecommunication networks. This implies studying the physics of photorefractive self-focusing and spatial solitons in  Iron doped Indium Phosphide (InP:Fe) which was chosen for its speed and its sensitivity to telecommunication wavelengths The first part is devoted to characterizing our samples through conventional photorefractive two wave mixing to measure the resonance intensity around which, the literature says, self-focusing is expected to happen. The second part is thus devoted to the experimental study of spatial soliton formation and propagation in InP:Fe. We have there evidenced a build up time shorter than 1 ms. Parallel theoretical studies have been conducted on the basis of the transport equations taking into account the two carrier types characteristic of semi-conductors. Our analytical derivations have shown a link between two-carrier semi-conductors and one-carrier doped insulators. Numerical simulations with less approximations have confirmed these results. We have thus explained successfully our experimental observations, while showing the need for a partial re-thinking of the existing theory. and help to understand the experimental observations, both through analytical studies and numerics. Theses studies have led to partially reconsidering existing theories.