Ray tracing technique and its verification for the analysis of highly multimode optical waveguides with rough surfaces

A novel hybrid ray tracing technique for the analysis of signal propagation in highly multimode optical waveguides with rough surfaces and its verification in part is presented. The technique combines geometrical optics with a light scattering model, based on wave optics by applying a Monte Carlo method. While the light scattering model takes mode coupling caused by surface irregularities into account, the ray tracing technique provides the analysis of light propagation in highly multimode waveguides with arbitrary shapes. The verification is obtained by calculating wave propagation within a slab waveguide with rough surfaces applying the well known coupled power theory, which provides the power of the guided modes versus the axial coordinate of the waveguide. Therefore, the ray tracing results are transformed into the discrete waveguide modes in order to compare the results.