Generation, manipulation and detection of NIR and MIR entangled photon pairs

The PhD thesis work here presented was carried out within the SiQuro project at the Nanoscience laboratory of the University of Trento. The project started in September 2013 and lasted four years. It was funded by the Provincia Autonoma di Trento (PAT). SiQuro’s goal was to bring the quantum world into integrated photonics by using the silicon platform and, therefore, permitting the integration of quantum photonics with electronics. The vision was to have low cost and mass manufacturable integrated quantum photonic circuits for a variety of different applications in quantum computing and secure communications. It must be said that SiQuro was a challenging and ambitious project, nevertheless important achievements in the quantum photonics arena were reached. My thesis is concentrated on the generation, manipulation and detection of quantum states of light. On one side, this was carried on in strained silicon waveguides, with the final goal to generate MIR entangled photon pairs via SPDC. Alongside, the generation and manipulation of correlated photon pair sources by means of spontaneous FWM in traditional silicon waveguides and microring resonators at telecom wavelength was also investigated. For the detection of MIR photon pairs, a suitable detection unit was developed as well. Moreover, even though the long-term goal of the project was the realization of a silicon quantum photonic circuit, I also implemented free-space quantum optical experiments. For this, I exploited a bulk nonlinear crystal, namely lithium niobate (LiNbO3), which has a well-known sizeable χ(2) nonlinearity.