Analysis and Design of a New Type Polymer Modulator Based on Asymmetric Mach-Zehnder Structure

An asymmetric path ridge waveguide for an organic polymer Mach-Zehnder modulator was designed to make the initial phase difference between the two arms be π/2. The mode characteristic is analyzed and the ridge waveguide is designed with effective index method (EIM). Optical field distribution has been simulated by Beam Propagation Method (BPM). Aiming at a smaller conductor loss and better impedance match, the structural parameters of electrode are also optimized. Combining with the parameters of the ridge waveguide and the electrode, velocities match between lightwave and microwave can be achieved. We showed that the thickness of the additional layer on the electrode must be taken into account because there is a significant change in the characteristic impedance. For our design, the estimated bandwidth of the asymmetric Mach- Zehnder modulator is over 150GHz.