Quantum physics has deeply changed the scientific perception of reality. The physical realization of quantum states is a vast resource for humankind: it can be used for a surprisingly large manifold of purposes; among those, the generation of truly random numbers, the possibility of distributing a shared private key for cryptography, or new ways to perform computation. Today, the most practical approach of creating and manipulating quantum states relies on playing with photons, i.e. light. Indeed most of quantum information processing experiments are accomplished via optical means. This situation is the consequence of the extraordinary development of photonic tools over the last decades, in terms of sources (lasers, quantum dots...), processing (optical fibers, filters, multiplexers, crystals, waveguides...), and detectors (photodiodes, superconducting nanowires, transition edge sensors...). "In this manuscript we present some (modest) contributions to the field, done during a PhD in the group of applied physics at University of Geneva (Switzerland)".