Three-demensional Entanglement On A Silicon Chip

Entanglement is a counterintuitive feature of quantum physics and is at the heart of quantum technology.High-dimensional quantum states have unique quantum proper-ties and offer advantages in certain quantum information and quantum computation tasks compared to the traditional techniques.For example,quantum communication have a larger transmission capacity,quantum computing and quantum simulation have stronger parallel capabilities.Photon,as a carrier of information,have many advantages such as various degrees of freedoms(DOFs),integration compatibility,and strong coherence,etc.Moreover,phton have inherent adavantages on generating useful entanglement state.Tranditional optical path is huge,and often the stability of optical phase is a big challenge.The integration technology not only reduces the size of the device,but also enables miniaturization and integration,and provides stable phase and ideal scalability.Integrated photonic chips have recently become a leading platform for the generation,manipulation and detection of entangled photons.Here,we report a silicon photonic chip that uses novel dual interferometric resonance-enhanced photon-pair sources(DMZR),spectral demultiplexers and high-dimensional reconfigurable circuitries to generate,manipulate and analyse path-entangled three-dimensional states,namely,qutrits.By minimizing on-chip electrical and thermal cross-talk,we obtain high-quality quantum interference with visibilities above 96.5%and a maximumly entangled qutrit state with a fidelity of 95.5%.We further explore the fundamental properties of entangled qutrits to test quantum nonlocality and contextuality and to implement quantum simulations of graphs and high-precision optical phase measure-ments.Our work paves the way for the development of multi-photon high-dimensional quantum technologies.The main study content of the thesis is following:(1)Studying the working principle of the DMZI source,we calculate the transmission spectrum by the method of transmission matrix and chain matrix,and then discuss and analyze under what circumstances it can achieve the optimal working state.And it is compared with the traditional resonant ring structure,which shows its superiority as a source of integrated entangled photons on the chip.Then we verify this inference through experiments,give the experimental optimization of the adjustment of the light source,and calculate the relevant parameters to verify that it can work effectively.(2)We theoretically studied the conceptual scheme of forming an entangled source by correlating photon pairs generated by spliting pump laser in the case of qubit,and then gave the experimental scheme to extend it to high-dimensional situation.Figure.The the relationship between the path entangled state and the sources indis-tinguishabilities are theoretically analyzed.Accordingly,the method of optimizing the high-dimensional entangled source in quantum experiments is given.The process of optimization and thereby the generation of the maximumly entangled state are shown.Quantum state tomography is employed to characterize the quantum state.In addition,we also show our the experimental details about minimizing the electric and thermal crosstalk.(3)With the generated high-dimensional entanged state,we have carried out the measurement of high-dimensional Bell inequality and verified the local hidden variable model.Quantum incontertextuality without compatibility loophole is also investigated.We also use this state to demonstrate the feasibility of quantum simulation experiments for graph theory,and the sensitivity of phase measurements over traditional three-path interferometers.