Research And Implementation Of Quantum Weak Coherent Single Photon Source

With the advancement and development of science and technology,quantum communication and single-photon source technology in its key technologies had been paid more attention.The single-photon source with quality and stability was a key factor.The single photon source used in quantum communication was generally obtained by strong attenuation through weak coherent light,but in the attenuated optical pulse,it was inevitable that there would be a multiphoton component,and the single photon component was less.The quantum information was easily eavesdropped.Therefore,a more accurate and stable photonic preparation scheme,temperature,drive and bias voltage design schemes were required to ensure the stability and consistency of the optical pulse,as well as the system's code rate and count rate.In order to solve the eavesdropping problem,a decoy mode scheme was adopted,and a decoy state light pulse was prepared in a novel manner to meet the needs of practical applications.The development of quantum communication and single photon were described in this paper.Then the single photon characteristics discussed,single photon preparation schemes were introduced,and the principle of decoy state was analyzed.Through the use of different performance of the driver chip,through the precise control of the logic and the host computer software,the data was analyzed and processed to achieve the highspeed control signal delay and processing,so as to obtain the required narrow pulse drive signal.The preparation of the decoy state was based on the principle of electroabsorption modulation,and its principle circuit was integrated into a new type of laser.The key signals output by the processed laser driver circuit,the key parameters such as frequency,pulse width,drive current and bias current satisfy the requirements,the pulse width range was adjustable,and the decoy circuit can simultaneously prepare the signal state and the decoy state light.The pulse,which satisfied the signal state light intensity as three times of the decoy state,solved the problem of photon number separation attack used by the eavesdropper on quantum information distribution in quantum key distribution.The single photon preparation scheme designed in this paper satisfied the precise requirements of the quantum key distribution for the light source,making the subsequent quantum information transmission and processing safer and more convenient.