Photonic circuits for wireless applications in the microwave, millimeter wave and terahertz bands
(English) This thesis focuses on the emission, processing and detection of electromagnetic radiation in applications where the use of established technologies may limit the achievable frequency or bandwidth. Leveraging hybrid photonic-electronic approaches, different technologies allowing unique acc...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2022 |
| País: | España |
| Institución: | CBUC, CESCA |
| Repositorio: | TDR. Tesis Doctorales en Red |
| OAI Identifier: | oai:www.tdx.cat:10803/692046 |
| Acceso en línea: | http://hdl.handle.net/10803/692046 https://dx.doi.org/10.5821/dissertation-2117-413480 |
| Access Level: | acceso abierto |
| Palabra clave: | Àrees temàtiques de la UPC::Enginyeria de la telecomunicació 621.3 |
| Sumario: | (English) This thesis focuses on the emission, processing and detection of electromagnetic radiation in applications where the use of established technologies may limit the achievable frequency or bandwidth. Leveraging hybrid photonic-electronic approaches, different technologies allowing unique access to extremely high frequencies and bandwidths are studied in this thesis. Considering the world wide use of optical communications, Microwave Photonics (MWP) filtering stands as a technology that can potentially transform the signal distribution leveraging the existing optical fiber infrastructure. An in depth analysis of Chromatic Dispersion (CD) effects on Microwave Photonic Filter (MPF) filters is presented, offering strategies to increase the MPF stopband attenuation. Phased Array Antenna (PAA) are widely extended for wireless communications, radar, radio-astronomy and many other applications, and are also identified as a field that can benefit from photonic technologies, as typical electronic implementations may restrict the usable bandwidth and received power, introduce frequency or bandwidth dependent distortions in the radiation pattern, usually related to issues implementing wide-band true time delays. MWParises as a promising solution whose advantages and disadvantages are elaborated. Looking at more advanced applications of antenna arrays, Aperture Synthesis (AS) is a technique used to recover the brightness distribution observed by an antenna array through interferometric measurements, which has attracted considerable developments in the field of MWP as photonic correlators can provide key advantages. We review the State of the Art of photonic correlators for AS, and develop an alternative implementation of a single baseline photonic correlator which substitutes the optical filtering stage by leveraging CD frequency-to-time mapping. A multiple baseline photonic correlator is also developed, allowing to compute many correlations simultaneously, introducing high scalability and avoiding the pitfalls of other similar developments, such as optical phase stabilization and extremely demanding spatial precision requirements. This multiple baseline photonic correlator has culminated in a patent submission. Our research also deeps in extending the frequency range up to the THz, where Photoconductive Antenna (PCA) based THz Time Domain Spectroscopys (THz-TDSs) stand out as a very popular research platform. However, challenging alignment requirements impact on such systems, typically limiting its use to a single setup configuration (e.g. transmission or reflection spectroscopy setups) and influencing the emission characteristics. Optimization and alignment of a THz-TDS system is deeply addressed, identifying different causes affecting the emitted pulse and its beam characteristics. We develop and test a simple yet powerful method to characterize THz emissions from PCAs, with promising applications for PCA development, THz-TDS imaging, THz Arbitrary Waveform generation (AWG), etc. We apply our method to characterize 12 different PCAs using a meticulous alignment procedure and signal post-processing, with experimental results showing the spatial beam distribution, frequency power spectrum, polarization measurements and Laguerre-Gauss modal analysis. To the best of our knowledge, this represents the larger amount of PCAs characterized in a study. The data obtained with our characterization method is used to demonstrate THz AWG through beam transformations with transmission masks. Modification of THz-TDS is further explored, with different setup configurations developed and analyzed to improve the measurements through customization for different types of samples and measurement requirements, including a THz interferometer. |
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