Lightwave circuits for integrated Silicon Photonics

This thesis work covers scientific and technological advancements in integrated silicon photonics circuits aimed at developing an All-On-Chip device for quantum photonics experiments. The work has been carried out within the framework of project SiQuro, where the Silicon-On-Insulator platform is chosen to integrate all the components of an optical bench necessary for a quantum experiment into a single chip. The problem of generating photon pairs have been addressed by studying second order polarisation effects in strained silicon with the aim to realize a bright photon pairs source based on Spontaneous Down Conversion. The study revealed that processes other than the Pockels effect are responsible for the non-linearity coefficients previously measured, suggesting to look for other candidate processes for the generation of photon pairs, as third order non-linear processes. To provide with the bright coherent source necessary to enable non-linear processes the integration of a hybrid III-V-silicon mode-locked laser has also been studied. During this study, technological novelties have also been developed by modelling the wedge profile obtained during the wet etching of silicon glass materials to engineer 3D structures. In parallel, the physics of whispering gallery mode resonators, both in silicon and in silicon glass materials, have been addressed. Silicon nitride Ultra High-Quality resonators have been demonstrated by using a strip-loaded configuration, while relative tuning of resonant modes has been demonstrated in an all-optical experiment exploiting the thermo-optic effect. This work represents a step forward in the study of the physics and applications of silicon-based lightwave circuits for integrated photonics.