The Research On Several Problems Of Quantum Network Based On Fiber Channel

Quantum information is an interdisciplinary subject combining quantum physics and information science.It has been developed for more than 30 years and its great advantages over classical information have been demonstrated on some problems,such as theoretically unconditionally secure quantum communication and parallel comput-ing with exponential speed-up compared to the classical counterpart.The global quan-tum network is an important platform for quantum fundamental theoretical research and quantum information technology application.In the picture of the global quan-tum network,quantum bit and quantum entanglement are basic resources.With the aid of quantum teleportation,quantum swapping,quantum memory and so on,the global quantum network can establish the quantum repeater,and complete security informa-tion transmission,quantum computing and high-precision quantum measurement tasks.This thesis focuses on the related problems in the optical fiber quantum network.The complex structure of quantum networks means complex physical processes and quantum properties.The first research work of the thesis is about the experimental demonstration of quantum non-bilocality via entanglement swapping.In the local hid-den variable models,when the entanglement sources are independent,we can assume that there exist a local hidden variable for each source,reasonably.And the research group of Gisin puts forward a bilocal inequation based on the assumption.we present an experimental realization of a five-node quantum network.We closed the measurement independence,locality,and quantum source independence loopholes simultaneously,and demonstrated violation of bilocal inequality in a quantum network.This experi-mental realization is not only quantum fundamental research,but also valuable for the design and implementation of future quantum networks,or maybe can appled in device independent quantum random number generator and device independent quantum key distribution.Quantum computing is the important part of quantum information.In the early development of quantum computer,due to the complexity and cost of the systerm,only large enterprises or research institutes will be able to own quantum computers.The clients delegate computational tasks to the powerful quantum servers based on the quan-tum network platform via blind quantum computing technology.In the second work of this thesis,we propose a remote blind qubit preparation(RBQP)protocol based on de-coy state,and we experimentally verify a key step of RBQP—quantum nondemolition measurement by using the quantum teleportation method in the field test over 100 km of fiber.This work is important for universal blind quantum computing and cloud quantum computing over long distance.Realizing long-distance entanglement swapping with independent sources in the real-world condition is important for future quantum networks.In the third part of the thesis,we introduce our experiment on 103 km entanglement swapping.We success-fully implement a field test of entanglement swapping over an optical fiber link of more than 100 km with loss of 29 dB.We exploit two independent 1 GHz-clock sequential time-bin entangled photon-pair sources to improve the system count rate.We develop several automatic stability controls to improve system stability.Our result verifies the feasibility of long-distance quantum networks.