Study Of Polymer Themo-optical Switch Based On Silicon

In this dissertation, we first introduce the development of the thermooptical(TO) switches, and then we introduce the basic principle of the thermooptical effect and the advantage of fabricating thermooptical devices by the polymer.The integrated optical chips we designed in the dissertation are the 1x2 multi-mode interferometer, the Mach-Zehnder TO phase modulator, the Y-branch switch and the total internal reflection(TIR) TO switches. In the design of the switches, taking into account the experimentation condition and process in our laboratory, we choosed the oversized rib waveguide structure. Because the cross-section of the oversized rib waveguide we fabricated by wet-etching was trapeziform, we analyzed the transmission of oversized rib waveguide by combining effective refractive-index method. The influence of some factors on the optical transmission loss, such as material structure, the height of rib waveguide, and the thickness and refractive index of waveguide layer and up-layer of polymer material, was analyzed. By thermal conducting method and the finite difference method, we also analyzed the heat diffusion in different material structures. According to the result of analysis and the fabricating technique of our lab, we designed the parameters of oversized rib waveguide and devices on the polymer/silicon material and simulated the behaviour of the devices by using the BPM method simulation soft named "BeamProP". According to the working principle of thermo-electrode , we demonstrate the structure of enlarged reflection area and the structure of step broaden waveguide to improve the switch's performance and bring down the driving power.According to the fabricating condition of our lab, we proposed simple wet-etching method to fabricate the oversized waveguides and peeling-off method to fabricate the electrode. We did much effectiveness researches in fabricating polymeric hull on silicon, and have obtained many useful process parameters.On the basis of the theoretical analysis, design and the study on the fabricating technique, the relationship between hull height and writhe speed, the output light which proves the single-mode condition, and the split peculiarity of output light ,was gotten.Through the work in this dissertation, the theoretical analysis, design and the study of the fabricating technique on the polymer/silicon-based integrated TO optical chip are all made certain achievements, which will be the basis for the development of the practical chip.