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The characteristics of the polymer modulator are determined by many interrelated physical phenomena. The key issue of this paper is to find out the optimum device parameters and corresponding conditions by taking into account all the related factors. The optical field in ridge waveguides is calculated using the FEM software with MATLAB and then fit to a Gauss function. The parameters such as half-wave voltage, bandwidth are calculated using the FEM software with FORTRAN language. In the calculating results, the comprehensive characterization of the polymer modulator with 1.21v half-wave voltage, 91GHz bandwidth is presented, electro-optic interaction length is 20mm, electro-optic coefficient is 55pm/V, and wavelength is 1.319μm. These results fit the 0.8v half-wave voltage, electro-optic interaction length is 30mm reported on Science perfectly. More important, five structures of polymer modulators are presented all together and are compared of the merits and shortcomings. One of them is a combination of CPW and microstrip lines. The characterization of this structure is like that of the microstrip lines with single arm electrode on one arm of the waveguide, but it solves the problem of microstrip-coaxial transition and corona polarization.

The characterization of Z-cut LiNbO 3 optical modulators with novel complex electrode are discussed by using the finite-element method (FEM) and studied experimentally in this paper. The calculation results show that the configuration of the electrode can realize microwave-optical velocity match easily and reduce microwave electrode losses drastically, so the modulators with such electrode are candidate devices for future ultra-high-speed optical fiber transmission systems. The traveling wave electrode consists of upper and lower parts. Because the thickness of the hot electrode can be thicker, the microwave attenuation coefficient of the traveling-wave electrode (alpha) 0 is able to be less than 0.35 dB/(cm GHz 1/2 ). The configurations of the electrode are optimized by criteria of the ratio of 3dB optical bandwidth to drive power. The results of optimization show that the properties of the modulators can be improved by increasing the electrode gaps. An electro-optic modulator with bandwidth 100 GHz, half wave voltage 6V is designed. The modulator is being fabricated in our laboratory. Some experimental results of the traveling- wave electrode are obtained. The characteristic of low microwave transmission loss of the electrode is demonstrated. The attenuation coefficient (alpha) 0 measured by microwave network analyzer is as low as 0.35 dB/(cm GHz 1/2 ).