This PhD thesis describes the realization of integrated optical components in Silicon-on-Insulator (SOI) material. In particular, the thesis is focused on the realization of Mach-Zehnder delay interferometers (MZ-DI) in 4µm SOI technology. As an example, the ability of MZ-DI for the demodulation of phase-modulated data signals is investigated. The thesis considers in detail the design of the basic components for the realization of MZ-DIs in SOI technology. These components are single-mode waveguides and multi-mode interference (MMI) couplers. Following simulations and iterations of the fabrication, these components can be realized with high-performance. Based on these components, the performance of the MZ-DIs is investigated. Typical extinction ratios are in the range of 30 dB. The polarization-dependent frequency shift (PDFS) is reduced to about 0.2 GHz. Furthermore, the hybrid integration of active InP components on SOI platform is shown. Based on flip-chip technology, this includes the realization of an integrated optical DPSK receiver and an integrated all-optical wavelength converter.