Considerations of optimum electrode structure for lumped constant type LN optical modulator in the microwave band with electromagnetic field simulator

We have developed micro-wave band (3.4-7GHz) lumped constant type LN optical modulators for voice and video program transmission. However, what type structures are the most suitable for sensitivity and operation at higher frequencies has not been discussed enough. In this paper, we considered the optimum electrode structure for our developed LN optical modulators operating at higher band (10GHz) with an electromagnetic field simulator. As a result, it was found that there is an optimum modulation electrode structure for both increased frequency and sensitivity; that bends in the electrode should be smooth in order to create a uniform refractive index for the optical waveguide along the length of the modulation electrode, and increase sensitivity; and that making the crystal substrate thinner is an effective way to increase the self-resonant frequency.