This thesis starts with an investigation of the local oxidation of silicon (LOCOS) technique to fabricate submicron-size photonic waveguides. Next, the thesis shifts the focus theme from fabrication technology to device designs. The first class of silicon devices that was investigated in this thesis is microring resonator (MRR)-based devices, two of which are targeted for label-free evanescent field sensing. The last MRR-based device proposed is an all-optical switch using a ring-assisted Mach-Zehnder interferometer (RAMZI), which is the essential building block for on-chip silicon photonic circuits. The second class of silicon photonic devices investigated in this thesis is subwavelength grating (SWG) structures for polarization management. The SWG structure features the unique engineering capability of the waveguide effective index. The third class of silicon photonic devices investigated in this thesis is taper-based devices. The taper-based devices are first applied in polarization management. One design is a polarization rotator (PR) using a tapered amorphous silicon layer, which can effectively reduce the insertion loss; while the second design is a PSR based on a taper-etched directional coupler (DC). The thesis also presented a two-mode (de)multiplexer using a simple taper-etched DC, where the fabrication tolerance was greatly improved by the tapered design. All the devices mentioned above were thoroughly examined through numerical simulations. A selective set of devices were fabricated experimentally. For example, the LOCOS wire waveguides were fabricated at the Carleton University MicroFabrication Facility; the MMI coupled slotted MRRs and the TE-pass polarizer based on SWG waveguides have been fabricated using deep ultraviolet (DUV) lithography by the OpSIS and IMEC foundry services through the CMC Microsystems.