The development of all-optical devices operating entirely with light promises significant advances in communication technologies. Control of light by light can be realised in nonlinear materials with optical properties dependent on light intensity. For example, the self-action of beams can result in suppression of diffraction spreading and formation of spatial solitons. Interacting solitons co or counter-propagating can enable passive or active optical components such as optical routers, reconfigurable interconnects and perform all-optical computations. The dynamic creation of waveguides in photorefractive semiconductors (InP:Fe, Sn2P2S6) is investigated in the case of a longitudinal soliton-like propagation of a self-focused near-infrared wave. The corresponding response time of the self-focused waveguide is of the order of tens of microseconds at telecommunications intensities. Systematic measurements of the fast photorefractive self focusing as a function of the beam intensity, the electric field applied and the temperature show two different characteristic time scales : one around the tens of Μs related to the transient regime and one of the order of several ms related to the steady state regime. A theoretical model simulating the temporal dynamic of the self focusing is developed and checked against experimental results. In the case of an exact balance between the diffraction and the nonlinear optical effect, the beam propagates as a spatial soliton and by interactions, simple or more complex optical functions as X or Y couplers can be realized. An other interesting application concern the self-alignment between a laser diode and an optical fiber by using counter-propagating solitons interactions. In such a case or for a photorefractive material in a laser cavity, the control of spatio-temporal instabilities is of practical interest.