Photonic structures can be used to confine and guide light in semiconductors, greatly enhancing its interaction with the materials as well as the optical nonlinearities. In this work we exploit silicon resonators, in particular microring resonators and photonic crystal cavities, to enhance the third order optical nonlinearities of silicon. We show that these devices act as microscopic and integrated sources of quantum states of light.
We experimentally study classical and spontaneous four wave mixing, showing theoretically and experimentally there is a definite relation between the two processes. We also demonstrate, using time correlated measurements, that the signal and idler beams generated in the spontaneous process come in correlated pairs. Finally, we prove that the signal idler pairs are time-energy entangled in a Franson type experiment.