Nonlinear optics in silicon photonic wires: Theory and applications

Silicon photonic wires (SPW) are deeply scaled silicon waveguides with transverse dimensions much less than 1 mum. Integrated silicon photonic devices based on SPW generally have very small footprint and very strong light confinement, which lead to many advantageous physical properties: capability for dispersion engineering, high optical-field density, enhanced effective nonlinearity, and intrinsically short carrier lifetime.; Third-order nonlinearities, dispersion effects up to the third-order and carrier effects are the three major contributors to the rich pulse dynamics in SPW. In this thesis, various nonlinear optical processes in SPW such as stimulated Raman Scattering (SRS), self-phase modulation (SPM), cross-phase modulation (XPM), modulation instability (MI), and third-order dispersion (TOD) induced soliton-radiation effect are studied theoretically and experimentally.; After a brief introduction of silicon photonics, I first present a comprehensive theoretical model developed from Maxwell's equations and the Lorentz reciprocity theorem for describing pulse dynamics in high-index-contrast and anisotropic waveguides. Chapter 3 focuses on exploring the capability of "engineering" the optical dispersion, which enables the control of phase matching of nonlinear pulse dynamics and is important to the development of nonlinear optical functionalities of SPW. In linear regime, SPW is shown to support wavelength-division multiplexing (WDM) transmission at an ultra-high-data-rate of 300 Gb/s for intra-chip optical network.; SPM is the result of optical Kerr effect, which manifests as an intensity-dependent refractive index change. In Chapter 4, SPM of optical pulses with temporal widths in both picosecond and femtosecond regimes is studied experimentally and theoretically. In the femtosecond regime, the interplay of nonlinear effects, group-velocity-dispersion (GVD) and TOD results in soliton-like pulse propagation in SPW. TOD-induced soliton radiation was demonstrated both numerically and experimentally.; Two-pulse interaction is the focus of Chapter 5. We experimentally demonstrated XPM using two femtosecond pulses and studied the time-resolved phase modulation as a manifestation of walk-off between these two pulses. XPM is also utilized to optically compress a weak 200-fs pulse propagating in the anomalous GVD regime. MI is a four-wave-mixing (FWM) process that is phase-matched by SPM. We demonstrated that strong MI can be observed in silicon photonic wires with lengths of only a few millimeters using numerical simulation. Our results suggest that MI can be employed to design on-chip optical sources with a highly tunable repetition rate.; SRS-based optical amplification in silicon waveguide is a significant functionality. In order to understand the detailed physical process of SRS in SPW, we use the model developed in this thesis to study numerically SRS-mediated pulse dynamics, such as Stokes pulse generation from noise and Raman amplification of Stokes pulse.; This work provides a comprehensive presentation of many fundamental nonlinear processes and dispersion effects in silicon photonic wire. It introduces the basis for developing compact active and passive functional devices for integrated silicon photonic circuits.