Organic Polymer Electro-optic Modulator To Optimize The Design

The electro-optic modulator which changes the electrical signal to the optical signal plays an important role in the optical fiber communication system. Firstly, the current development and trends of the polymer electro-optic modulator at home and abroad were introduced. Secondly, the structural characteristics and the characteristic parameters of the electro-optic modulator are described in detail based on the basic physical theory of modulation, and this dissertation makes an intensive study of waveguide and electrode.Start with the theory of optical waveguide, the transmission modes of waveguide were analysis theoretically. Combined with the advantage of organic polymer materials, the theory analysis, the modeling and simulation of the organic polymer rib waveguides were achieved by using Matlab Language based on the theory of EIM: the waveguide mode field were simulated under the different variable sizes of core layer thickness of the organic polymer waveguides, ridge high and ridge width. The influence of these variables on the effective refraction index was analysis in detailed, and the single-mode transmission conditions of the organic polymer ridge waveguide were obtained. Simulating the optical field of the waveguide structure which meets the condition of single-mode transmission through the OptiBPM Analyzer, we found that simulation results is single-mode transmission and the central area is limited to ridge area.Based on the theory of BPM and the structure of Y branch, the theory of cosine type Y branch waveguide bend was analysis and its' model was simulated by using Matlab Language. The relationship between branch height, waveguide width, the length of the transition zone and loss were analysis. The final optimized Y-branch waveguide parameters are obtained by modeling and simulation the cosine respectively symmetric and asymmetric Y branch waveguide bend through the software of OptiBPM Analyzer.In the end, a new electrode structure is designed, which has the advantages both of the traditional coplanar waveguide electrode and the in-plane coplanar waveguide electrode. It is improved the electro-optic effect and the difficult of the design of the electrode region. Secondly, the factors which impact the impedance, loss and half-wave voltage are analysed. Finally, three different transition structures of electrode are designed and compared, and found that transition of an elliptical asymptote bend makes the transition of electrode smooth and continuous. The 3dB modulation bandwidth value is also obtained using the elliptical asymptote bend.