Ultra-compact Optical Modulator Based on Silicon Photonic Crystal Waveguide

Nanophotonics promises to have a revolutionary impact on the landscape of photonics technology. Due to the maturity of sub-micron silicon CMOS technology, nanophotonics on silicon is anticipated to play a critical role in future nano-system integration. In this program, we propose an innovative approach to building ultra-compact silicon Mach-Zehnder(MZ) modulators. The proposed structure consists of carefully designed photonic crystal waveguides(PCW) in conjunction with a metal-oxide-semiconductor(MOS) "capacitor," which utilizes plasma dispersion effect to achieve high-speed modulation. Incorporating the PCW nanostructure provides an unprecedented opportunity to enhance the modulation efficiency of silicon based MZ modulators, and a reduction of electrode length by 100 times is expected. The ultra-short electrode length associated with the highly dispersive PCW nanostructure brings such exclusive advantages as low power consumption, high bandwidth, and potential for high-density integration of modulator arrays, which promises to outperform existing silicon guided-wave devices by at least one order of magnitude. To prove the feasibility of the proposed idea, photonic crystal waveguide based silicon MZ modulators will be designed, fabricated, and characterized in Phase I. The dispersion of the photonic crystal waveguides and the modulation characteristics of the MOS structure will be carefully investigated.