Fundamental And Application Studies Of Nonlinear Optics In Three Types Of Optical Waveguides And Structures

Nonlinear optics is the science that investigating the interactions between light and matters, which has been under sustainedly and fast development since the inception of laser and became one of the elementary branches of modern optic physics. Particularly, on one hand, by exploring the nonlinear light-matter interactions, people have found effective tools to probe the intrinsic structures and features of various matters. On the other hand, the light-matter interactions also convey people a viable methods to modify and control light fields, based on which optical signal processing technology was born and developed. Meanwhile, thanks to the rapid progress of material science and fabrication technology, novel materials and structures constantly appear, providing new platforms, mechanisms and methodologies for the studies and applications of nonlinear optics.This dissertation focus on the fundamental studies and practical applications of nonlinear optics in several types of optical waveguide structures, including: highly nonlinear optic fibers, slow-light silicon photonic crystal waveguide, and microring resonators constructed with silicon wire waveguide. The innovative results achieved in this dissertation are summarized as follows.The first is about the soliton dynamics in Silicon photonic crystal waveguide(PhCW) under the effects of both Kerr and free-carrier nonlinearities. The contents and innovations include:(1) The first experimental verification of the s4 slow-light scaling of free-carrier effects in PhCW.(2) The first experimental observation of soliton temporal acceleration and spectrum blueshift. Particularly, 2.3 ps wide input pulse is tunably accelerated by 2.6 ps in a 1.5 mm PhCW.(3) The first experimental observation of asymmetric spectrum broadening of higher order soliton induced predominately by free-carrier dispersion(FCD).(4) The first analysis of soliton dispersive wave perturbed by FCD in Silicon waveguide.(5) The first experimental characterization of the stability of FCD induced continuum generation in Silicon PhCW, using dispersive-Fourier transformation technology.(6) The first demonstration of free-carrier induced coherent wave-mixing and its unique features.We believe these original studies of ultra-short pulse dynamics in PhCW could provide very useful information for further design and applications of Silicon photonic devices.The second is about the dynamics of Kerr frequency comb in micro- resonators. Main contents and innovations include:(1) The first analysis of the stability of dissipative cavity solitons(DCS) in Kerr frequency comb, using the Lugiato-Lefever equations(LLE). Several key effects that disturb DCS in micro-resonators are pointed out and carefully discussed.(2) The first propose and experimental demonstration of Kerr comb phase-locking using phase-modulated pump. Particularly, using phasemodulated pump with ~200 mW average power, a phase-locked Kerr comb spanning more than 300 nm is generated in a 400 micron diameter Si3N4 microring resonator, and temporal oscillating pulse-train with less than 300 fs temporal width are also generated at the repetition rate of more than 100 GHz. The mechanism of pump phase-modulation scheme for comb phase-locking is thoroughly analyzed using LLE model.(3) The first characterization of FWM in Silicon microring resonator under the influence of dual-pump thermal dynamics, and a synchronous pump scanning method are proposed and experimental demonstrated to have the best efficience of FWM in micro-resonators.The third part is about the nonlinear optical effects in highly nonlinear fibers(HNLF) and their functionalities in all-optical signal processing technology and all-optical networkings. The contents and innovations include:(1) The propose and demonstration of a optimization scheme for FWM based all-optical amplitude reshaping in HNLF. Particularly, the scheme utilize Kerr nonlinear phase shift to control the phase-matching and generating efficiency of FWM idlers, so that to construct favorable power-transfer function for amplitude reshaping. In the reshaping demonstrations for real 10 Gbps OOK signal, extinction ratio of the reshaped signal is improved as much as 360%, the quality-factor improved by 290%, and the BER-free receiving sensitivity improved by more than 3.0 dB compared with the degraded signals.(2) The propose and demonstration of 3-input all-optical reconfigurable logic gate for frequency-shifted keying(FSK) optical signal, using FWM in HNLF. In the experimental validation, all 8 logic operations of three 20 Gbps FSK signals are demonstrated, output resulting signals are with good quality;(3) The propose and demonstration of a wavelength-correlating(WC) receiving scheme for OCDMA system. The proposed scheme using FWM to all-optically discriminate the autocorrelation peaks of decoded OCDMA codes. Based on the theoretical BER calculation, the proposed WC receiving scheme possesses much better receiving reliability than conventional OCDMA receiving schemes that rely on optical-electrical conversion and electrical power thresholding;(4) the demonstration of an optical packet switching system using multiple optical-orthogonal code labels.