Theory of polarization-dependent amplification in a slab waveguide with anisotropic gain and losses

We analyze the waveguiding properties of a semiconductor slab waveguide amp lifier in which the gain (i.e., the permittivity) in the quantum well (QW) is taken to be anisotropic. Losses may be present simultaneously in the cla dding layers. Using scattering theory, a rigorous integral equation is deri ved, Our model incorporates the two main causes of polarization sensitivity of the amplification, viz,, 1) waveguiding and 2) the anisotropic light-ma tter interaction in the QW, It is determined how much anisotropy is needed in the QW to get a polarization-insensitive amplification. Also, reflection coefficients and TE/TM mixing are studied. A comparison between the exact results and the Born approximation is made. A Green's tensor for a layered structure with losses is derived.