STABILITY ANALYSIS OF EVEN AND ODD WAVES OF SYMMETRICAL NONLINEAR PLANAR OPTICAL WAVE-GUIDES

In terms of the known surface wave stability characteristics of the simpler single-interface problem, we have explained the known stability behavior of antisymmetric and symmetric solutions of a linear core sandwiched between two nonlinear media. Our method considers the lateral shift of the nonlinear surface wave on one interface caused by the wave on the second interface. The appearance of complex growth rates in the case of the antisymmetric solution is explained by using this method. We show that the antisymmetric wave is stable at high values of the propagation constant, in contrast to the symmetric wave. We give simple physical explanations for the difference in stability results for the symmetric and the antisymmetric states in terms of a general physical principle, according to which a particle combination with less energy than the sum of the energies of its constituent states is stable.