Advanced silicon photonic modulators

Abstract

Various electrical and optical schemes used in Mach-Zehnder (MZ) silicon plasma dispersion effect modulators are explored. A rib waveguide reverse biased silicon diode modulator is designed, tested and found to operate at speeds up to 13 GHz with a V"L of 1.2 Vcm. MOS capacitor modulator designs are investigated as an alternative, but are not found to offer significant advantages. Modulators are also designed for fabrication in an actual CMOS process -a crucial step in the quest for low-cost integration with modern electronic devices. Photonic crystal structures, which promise smaller footprint sizes and lower power requirements, are also investigated, but it proves difficult to obtain a physically feasible design. Finally, a linearization scheme for Mach-Zehnder modulators is proposed to significantly improve signal fidelity in analog applications. Simulations are used to demonstrate the effectiveness of this scheme for reverse biased silicon diode modulators.