Design And Transmission Properties Analysis Of SOI Optical Waveguide Device

Now with the development of integrated circuit to smaller size, the electrical interconnection, which has become the main bottleneck of IC industry, can hardly meet the requirement. So using optical interconnection in place of metallic interconnection has become a practical and feasible solution. In this paper, we design and analyze the SOI waveguide devices in optical interconnection. It mainly includes the following research works.Firstly, based on the effective index method(EIM), the mode characteristics of the ridge shaped SOI waveguide are studied. In order to determine the single-mode working conditions, we compute the effective index of slab waveguide with different thickness by using both geometrical optics and two dimensional beam propagation method(BPM). The result shows that there is little difference between them, about 10-6. Based on this, the structure parameters are determined. The excess loss of the waveguide is only 0.02 d B when its length equals 10000μm.Secondly, with three dimensional BPM, multiple types of Y-branch waveguides are designed and optimized. The results show that the straight branch type, whose excess loss increases dramatically with the increase of branch angle, can only be applied to small angle. For the S-type Y-branch waveguide, the excess loss can be reduced by introducing bias to the waveguide junctions and increasing the radius. Then we draw a conclution that the excess loss of the three types of S-type Y-branch waveguide has an order of Cos-S<Arc-S<Sin-S when both the longitudinal transmission distance and branch spacing are the same. Based on these, the minimum excess loss can be only 1.86 d B when the branch angle is 10o.Thirdly, we design several types of multi-mode interference(MMI) optical couplers. With three dimensional BPM, we correct the result of traditional guided mode transmission method, based on which we design three types of MMI optical couplers, especially the symmetric type which has a smaller size. After optimized by fixing the output waveguide position and inserting tapered waveguide, the excess loss and uniformity drop respectively to 28% and 5% as small, which reach respectively only.33 d B and 0.00209 d B, and in C band and L band, its performance is greatly improved as well. In addition, the tolerance of the multimode waveguide width expands to 39.6μm-41.0μm with the same standard.At last, we design and optimize the SOI optical switch. Based on the electro-optic modulation mechanism, the electrical structure is simulated with ISE-TCAD. The result shows that we can improve the modulation efficiency by increasing the doping concentration and depth as well as reducing the distance between the doping area and ridge area. Then we design three types of optical switch including 1×1type, 2×2type and 1×4 type, whose excess loss are all below 1.55 d B.