Advanced photonic signal processing and hybrid integrated microwave photonic systems

In this thesis, we address the interdisciplinary research field known as “microwave photonics” (MWP), which has attracted considerable interest in scientific and industrial communities, and we investigate how integrated photonic technologies can be exploited to realize integrated microwave photonic systems. In brief, microwave photonics explores and develops methods and technologies to generate, process and distribute microwaves, millimeter waves and terahertz radiation via a photonic approach, i.e. in the optical domain. The main motivation for this approach is that systems based on microwave photonic technology can benefit from several advantages that are inherent to optical systems, such as high speed, low and frequency-independent propagation loss and reduced electromagnetic interference. However, although there is an indisputable and significant potential of microwave photonics, it has not yet been applied in real contexts. The main reason is that microwave photonics so far had to rely mostly on discrete components, which render according microwave photonic systems bulky, unstable and fragile. In order to overcome these limitations, while still taking advantage of the named, great opportunities, research and technology have begun targeting integration of microwave photonic systems, with the goal to enable the processing of microwave and millimeter waves via photonic chips.