Optical domain self-heterodyne microwave subcarrier generation and modulation

There is mounting interest in applying photonic techniques in telecommunication applications. This thesis concerns the optical domain generation of a frequency agile microwave carrier with sophisticated modulation capabilities. Specifically, an optical time delay self-heterodyne (TDSH) arrangement has been considered and demonstrated for microwave signal generation and modulation. The approach is suitable for Radio-over-Fiber (RoF) applications as it eliminates the microwave circuitry from the transmitter, and provides the complex modulated microwave subcarrier directly in the optical domain. The generated signal can be directly routed optically to remotely located antenna stations.;The signal generation concept is studied analytically with different modulation formats. The phase noise analysis of the transmitter is performed based on the laser's optical spectrum and the spectral properties of the fiber induced phase noise. It is shown, that the high-pass phase noise filtering characteristic of the TDSH provides for inherent frequency stability of the heterodyned microwave signal, therefore stable frequency operation can be provided without external feedback.;Proof of concept experiments focus on the experimental verification of the theoretical analysis. For these experiments a bulk electro-optically tunable Nd:YVO4 microchip laser is used as tunable optical source, and the rest of the optical system is realized by means of fiber optic components and LiNbO3 based phase and intensity modulators. The experiments demonstrate the principle of operation of the TDSH device and the optimization of the setup using presently available components.;Unlike many other complicated signal generation techniques, the simplicity of this arrangement and the common substrate material of the used components provides for the potential of photonic integration based on standard LiNbO 3 technology. The feasibility of photonic integration and the expected improvements are detailed.