Photonic Pulse Shaping Techniques for Arbitrary Waveform Generation

The motivation of this thesis is to explore the generation of arbitrary microwave waveforms through photonic means, showing the advantages they may offer. Some techniques will be presented for this purpose, as well as their applications. Firstly, the technique known as Direct Space To Time Mapping (DST) will be presen-+ted, which as the name properly says, turns the spatial profile into the time profile of the beam. Then, we will present the main technique of the thesis, which shows a great analogywith the DST. This technique is known as Frequency to Time Mapping (FTM) orDirect Fourier Transformation (DFT). In order to derive the expressions needed for the understanding of the DFT, dispersion theory in media will be explained starting from the macroscopic Maxwell equations derived in the appendix. It will be seen how combining spectrum shaping techniques along with the DFT we are able to generate an arbitrary radio-frequency waveform. After being mathematically derived, simulations will be performed to put numbers and further prove of the theory. The achievable time bandwidth product (TBWP) will also be derived and later compared to the one obtained by Matlab simulation. Furthermore, the DFT will then be applied for time reversal by photonic means. A microwave signal up to 10 nanoseconds long can be time-reversed using fibers, as it will be proved in theory and simulation. Applications related to these microwave generation techniques will also be explored, showing the research interest of this cutting-edge discipline