Modal analysis of a planar waveguide with gain and losses

In this study, we analyze the waveguiding properties of a planar waveguide amplifier in which losses and gain can be present simultaneously. It is found that the subsequent modes comprise both loss and gain modes. Also, the dependence of the gain on the state of polarization turns out to be significant for realistic dielectric structures. For strong losses or gain, the standard transfer matrix approach may become numerically unstable, therefore, a scattering matrices formalism is employed. A semiconductor-like gain profile enables us to study the gain as a function of ω for realistic laser amplifier structures