Modal gain in coupled-stripe lasers

Using an effective index model, we calculate the eigenvalue equation for a large array of evanescent-wave-coupled multistripe lasers. The special cases of symmetric and antisymmetric modes for both the index- and gain-guided lasers are treated in detail. The main findings are 1) weak index-guided coupling, with small differences in optical confinement factors, and 2) stronger gain-guided coupling, with parameter-dependent selection of the mode symmetry having higher gain.