Self-trapped bidirectional waveguides in a saturable photorefractive medium.

A time-dependent model for the generation of joint waveguides by counterpropagating light beams in photorefractive crystals is introduced. Depending on initial conditions and parameter values, the beams form stable structures or display periodic and irregular dynamics. Steady-state solutions nonuniform in the direction of propagation are found, representing a general class of self-trapped waveguides that include counterpropagating spatial vector solitons as a particular case.