Generating, manipulating, distributing and analysing light's quantum states using integrated photonic circuits

• Main Author: Wang, Jianwei
• Published: University of Bristol 2015
• Subjects: 621.36
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.702227

The emergence of integrated quantum photonics is revolutionising the field of photonic quantum information science and technology. Quantum photonic waveguide platforms, capable of integrating single photon sources, quantum optical circuits and single photon detectors on semiconductor chips by exploring mature micro- or nano-fabrication technology, greatly promise unprecedented complexity, miniaturisation, scalability and robustness for advanced quantum information applications, including quantum communication, sensing, simulation, machine learning and computing. This thesis is to continually enlarge the scope of integrated quantum photonics technology by developing new materials, devices and systems for new functionalities including generation, manipulation, transmission, distribution, interconversion and measurement of photonic quantum states. Gallium arsenide waveguide quantum circuits are first developed to manipulate photons, demonstrating two-photon quantum interference in integrated beamsplitters and manipulation of photon number entanglement in optical interferometers utilising the linear electro-optic effect of gallium arsenide. We also demonstrate a chip-to-chip quantum photonic interconnect, by demonstrating high-fidelity entanglement generation, manipulation, transmission, distribution and measurement across two separate integrated silicon quantum photonic chips. A highfidelity interconversion of path and polarisation encoding preserves coherence across the full interconnected chip-to-chip system. This would allows quantum information encoding, processing and analysing on chips and quantum information transmission and distribution across chips, towards the multi-chip and multi-core quantum systems. We report on-chip generation of high-purity orbital angular momentum states and the fast-speed reconfigurability and switch-ability using an ultra-compact integrated silicon microring resonator embedded with angular diffractive gratings. Quantitive and qualitative measurements are performed to analyse the orbital angular momentum states from the chip. This might allow a high-capacity quantum interconnectivity of free space and integrated quantum circuits for many quantum information prototypes. This thesis demonstrates the capabilities of on-chip encoding, controlling, transferring and analysing quantum states in photon's path, polarisation and spatial modes degrees of freedom, providing a new generation of integrated quantum photonics toolbox for future quantum information technology.