Research On Local Light Scattering Of Highly Multimode Optical Waveguides With Rough Surfaces

With the development of science and technology, optical interconnects are gradually replacing electrical interconnects. As well-known, optical interconnects have replaced electrical interconnects in the long-distance communications. However the requirement of data rates of internet switches and high-end computers makes it important to use optical interconnects to over come the evident high-speed interconnection bottle-neck. It leads to a broad development of the technology of board-level optical interconnects: electrical-optical circuit board (EOCB).So there is a huge need for modeling and simulation algorithms and tools of the optical multimode waveguides which is the most important component of the EOCB. However, due to the huge number of modes leading to a huge numerical complexity, established numerical methods for the analysis of optical waveguides like beam propagation method (BPM),finite-element method (FEM) and FDTD method are not applicable. Professor Elmar Griese presented a new method which was based on geometrical optics: ray tracing methods.Ray tracing, which is based on the classical laws of geometrical optics, can be used whenever the waveguides' geometrical size is much larger than the optical wavelength. But the classical ray tracing requires sufficiently smoothed dielectric interfaces and tracks only one trajectory throughout the waveguide simultaneously. Due to the manufacturing process of the waveguides, surface roughness will lead to scattering, so the classical ray tracing has to be extended in order to consider the reflection and transmission behavior of rough dielectric interfaces. In this paper, we implemented the model that local light scattering of highly multimode waveguides with rough surface. A large number of experiments have been carried out based on our analyzing program of the algorithm. Then a further analysis of the simulative results was taken, and we obtained many transmission characteristics of highly multimode waveguides. In order to solve the borderline condition problem of ray tracing method, we demonstrate how to use a statistical method with Monte Carlo theory to specify the track of the ray. Therefore, an extended ray tracing algorithm has been used to simulate and analyze the highly multimode waveguides with rough surface.