Experimental Study Of Quantum Random Number Generation

The combination of quantum mechanics and information science leads to the birth of a new discipline—quantum information,which includes quantum computation and quantum communication.Quantum communication can provide an unconditionally secure way of communication in theory and has come to the practical stage after several decades of rapid development.In the development of quantum communication systems,key devices and technologies play a vital role.In fact,the fierce international competition in the field of quantum communication has evolved into the competition in the development of key devices and technology such as single photon detection and random number generation.In the random number generation technology,the one which generates the true random number based on the basic principle of quantum mechanics is called quantum random number generator(QRNG),where the randomness comes from the objective randomness of the quantum physics system.Since the quality of the random number used in the quantum communication system is directly related to the security of the overall system,QRNG has more advantages compared to others and naturally became the key devices and technology of quantum communication.The main work of the author is experimental study of QRNG,which is mainly foced in the development of practical usage and the security under realistic conditions.In the practical aspect,we researched high-speed QRNG technique based on different schemes including photon arrival time measurement,laser phase fluctuation measurement,and developed a real-time high-speed QRNG module.These works provide feasible solutiones for quantum random number demand of future ultra high speed quantum communication system and promote the practical process of QRNG.In the security aspect under realistic conditions,we experimentally realized a measurement-device-independent(MDI)QRNG(MDI-QRNG)for the first time,which can effectively solve the problem of the min-entropy estimation error caused by the measurement of QRNG under realistic conditions as well as the resulting security risk.In the thesis,we introduce the concept,principle,scheme of QRNG and the author's experimental study works of QRNG during his doctoral period.In the study of QRNG based on photon arrival time measurement,a practical and fast quantum random number generator based on the measurement of the timing of single-photon detection relative to an external reference is proposed and realized.The distribution of the raw data is uniform and the raw random bit rate can reach 109 Mbps.In the study of QRNG by measuring laser phase fluctuations,we experimentally realizate a 68 Gbps QRNG.Compared to the fastest QRNG previously,the rate is increased by an order of magnitude.To meet the requirement of a stable interferometer.active feedback instead of common temperature control is developed for the phase stability.To close the gap between experimental demonstration and practical usage,we developed a fully integrated 3.2 Gbps QRNG module and implemented a pipeline extraction algorithm based on Toeplitz matrix hashing in a high-speed field-programmable gate array(FPGA).In the security aspect under realistic conditions,we experimentally demonstrate a measurement-device-independent(MDI)QRNG(MDI-QRNG)based on time-bin encoding to achieve certified quantum randomness even when the measurement devices are uncharacterized and untrusted.With a clock rate of 25 MHz.the MDI-QRNG generates a final random bit rate of 5.7 kbps.Such implementation with an all-fiber setup provides an approach to construct a fully integrated MDI-QRNG with trusted but error-prone devices in practice.