Technologies based on quantum mechanics promise to revolutionize
the collection, processing and communication of information.
However, due to the fragility of quantum coherence, complex
quantum states can only exist in highly isolated and stable
environments. One suitable environment is that of a quantum
photonic chip. Quantum integrated photonics seeks to generate,
process and detect complex quantum states inside a photonic
chip. This thesis presents theory and experimental verification
of novel approaches for the integration of various
functionalities
into quantum photonic chips in a scalable way. As such, this
thesis encompasses a broad area of physics including quantum
optics and nonlinear photonics.
The results presented in this thesis have applications in the
areas of quantum enhanced measurement, communication and
information processing. In particular we develop the theory and
experimentally demonstrate flexible on-chip sources of spatially
entangled photons, the state of which can be reconfigured
alloptically.
We show how such techniques could enable the realization
of simple cluster state quantum computing algorithms
using spatially encoded two-photon states. Furthermore, we
suggest new and practical approaches for the efficient
characterization
of mass produced nonlinear quantum photonic chips.
Finally we develop and experimentally demonstrate a scalable
method for the full quantum state tomography of multi-photon
states on-chip. Importantly this technique only requires a
linearly
increasing number of single photon detectors relative to
the number of photons in the state being characterized, and is
also highly compatible with on-chip single photon detectors
