Phase conjugation in stimulated Brillouin scattering (SBS) from an optical waveguide is studied numerically, using a Cartesian two-dimensional propagation code (BOUNCE) that includes pump depletion. The simulations show that light scattered back through a phase aberrator produces a far-field profile closely matching that of the incident beam; however, the near-field intensity exhibits large and rapid spatial inhomogeneities across the entire aberrator, even for conjugation fidelities <i>H</i> as high as 98%. This effect can be only partially removed by spatial-filtering techniques. The dependence of <i>H</i> on SBS gain, scattering length <i>L</i>, and the average intensity <i>Ī</i> and angular divergence θ<sub><i>D</i></sub> of the pump beam is first studied in the low-reflectivity regime (i.e., ignoring pump depletion). For amplitude gains ≳<i>e</i><sup>10</sup>, <i>H</i> decreases monotonically with the factor <i>Ī</i>/θ<sub><i>D</i></sub> that is due to a small-scale intensity pulling effect. This result appears to be independent of whether θ<sub><i>D</i></sub> arises entirely from the aberrator or from a combination of the aberrator plus curvature introduced by a lens. In all cases, pump depletion is found to enhance the fidelity by inhibiting the small-scale pulling effect. Under appropriate conditions, this can actually reverse the intensity dependence of <i>H</i> seen in the absence of pump depletion.
R. H. Lehmberg, "Numerical study of phase conjugation in stimulated Brillouin scattering from an optical waveguide," J. Opt. Soc. Am. 73, 558-566 (1983)