RF Frequency Doubling Using a Silicon p-i-n Diode-Based Mach–Zehnder Modulator

We demonstrate frequency doubling at 1 GHz using a new silicon Mach-Zehnder modulator (MZM). Modulation of the refractive index of silicon for an MZM action is achieved via the injection/depletion of electrons and holes in a p-i-n diode. The silicon MZM used in the experiment shows high phase-shift efficiency and a V_piL_pi of 1.88times10^-2Vldrcm which is nearly 350 times smaller than those of previously reported LiNbO₃-based MZM. Also, a theoretical analysis of frequency doubling in the time domain shows good agreement with the experimental results.