Omni-junction silicon modulators of unequal proportions for high-speed datacom

Abstract

Doping profiles are always a key factor in the design of silicon modulators. As the doping in the waveguide cross-section is limited by the compact footprint, three-dimensional complex optimization presents itself as a viable option for improved performance. This work proposes two different types of unequal-proportioned omni-junction modulators obtained by the linear-decline weight particle swarm optimization algorithm with appropriate figure of merits (FOM). With FOM targeting at overall performance, the obtained modulator composed of unequal-proportioned vertical and lateral junctions has high bandwidth of 40 GHz with the VπL of 1.07 V cm. With FOM for higher modulation efficiency, the modulator composed of unequal-proportioned U-shaped and L-shaped junctions demonstrates low VπL of 0.72 V cm and bandwidth maintaining over 36 GHz. The algorithm together with the 3D design method provides greater flexibility in improving the device performance.