| In electronics industry, silicon has been served as an enabling material for a few decades. Recently, by taking advantages of ultrahigh bandwidth in the optical domain, silicon photonics has attracted a lot of attention. More importantly, advances in silicon photonics have potentially paved the way for the design and construction of a CMOS-compatible optoelectronic integration system. In the first part of this dissertation, we design high-contrast grating hollow-core waveguide for linear systems, polarization rotator and splitter for integrated polarization diversity system. Dispersion and nonlinearity properties of silicon waveguide are tailored using different structures and materials for different communications and signal processing applications. A scheme for generating ultrawideband monocycle pulse in a silicon waveguide is experimentally demonstrated.;Fueled by the ability to transmit long distance, optical fiber communications will undoubtedly continue to grow. One of the critical issues in optical communications research is the challenge of meeting the needs of the inevitable growth in data transmission capacity. Besides wavelength, polarization, amplitude, phase of the optical field, researchers start to multiplex data channels carried by different and orthogonal spatial modes. In the second part of this dissertation, we propose and analyze the use of orbital-angular-momentum modes for spatial multiplexing in the ring fiber. As2S3 ring PCF is proposed and designed for supercontinuum generation or vortex modes, making OAM modes very promising in many optical signal processing applications. Moreover, we demonstrate mode-division and wavelength-division multiplexing of OAM modes through 1.1-km of vortex fiber. |
