A new method is proposed for semiconductor quantum well (QW) shape optimization in respect to the electro-optic coefficients. It relies on iterative solving of the system of coupled Schrödinger equations, which determine the wave functions of relevant states, and of Euler–Lagrange equations derived by applying the variational calculus to the target functional, with the starting potential supplied by the simulated annealing. Due to the combined use of the two methods, one may expect to get the globally optimal QW profile. Numerical example is presented for an AlxGa1−xAs based structure.