This article describes a newly developed physics-based approach to calculating the optical properties of III-V semiconductor heterostructures for active photonic device modeling. The consistent microscopic formulation of the complex permittivity in bulk and quantum well layers, in combination with the rigorous solution of the light propagation in absorbing multilayer structure with uniaxial anisotropy, provides a powerful tool for the design and simulation of the real life devices. As modeling examples, InP-based edge-emitting and vertical cavity laser structures are analyzed regarding free carrier effects on their optical properties.