Performance Analysis Of Wavelength Conversion By Four Wave Mixing In Silicon On Insulator Waveguides

This thesis is dedicated to study optical wavelength conversion by Four Wave Mixing (FWM) in silicon-on-insulator (SOI) waveguides with an emphasis on third-order nonlinearities. The intention is to understand the nonlinear effects inside SOI waveguides, the possible applications of SOI waveguides, devices manufactured using this technology and the inherent obstacles this structure faces for some of the fruitful applications. Silicon-on-insulator nanoscale optical waveguides can have transverse dimensions substantially smaller than the wavelength of the infrared light they carry. This extreme confinement provides very strong dispersion, which can be greatly controlled by specifying the waveguide geometry. The confinement also enhances silicon's already considerable Kerr nonlinearity (whereby refractive index increases with optical intensity), allowing for nonlinear optical phenomena with record-breaking small powers. It then focuses on some examples of nonlinear phenomena inside silicon on insulator waveguides, including a theoretical discussion of four wave mixing and using it for all optical wavelength conversion. The "Four Wave Mixing" process in SOI waveguides is discussed with an emphasis on the effects of two-photon absorption and the consequent free-carrier effects. We describe the optimization of wavelength conversion and the effect of different parameters on conversion efficiency. The theoretical work is given first followed with our simulation results that show successful all-optical wavelength conversion using single pulsed pump light. The ending chapter deals also with the losses due to two photon absorption and free carrier absorption, and how to decrease these losses in our simulations with SOI waveguides.