Traveling wave electrode simulation for integrated lithium niobite electro-optic modulators

With the improvement of information transmission rate and the progress of semiconductor process technology, Lithium Niobite on insulator (LNOI) electro-optic modulators have received more and more attention. The LNOI modulators have high linearity and extinction ratio that silicon-based modulators do not reach, so it can be used to support high-speed and long-distance optical communication. In the LNOI modulator, the traveling wave electrodes with coplanar waveguides (CPWs) structure are used. We mainly consider the impedance matching of microwave transmission, the velocity and loss of microwave and optical wave to obtain high-speed modulation devices. By means of Simulation, we get the optical waveguide single-mode condition and analyze the characteristic impedance, microwave effective refractive index and 3dB bandwidth of the electrode under that condition. The electrode with bandwidth of 70GHz and 𝑆11 about -25dB is obtained.