Research On Detecting Precision Of Photon Polarization Based On Fore Path Gm-APD Detectors

Radar detection in the widely used military-industrial detection, meteorological observation and scientific research and other fields. With the improvement of application requirements, requirements can accurately detect and identify further, smaller targets, detecting such targets the echo signal often has only a few photons. Traditional radar due to power and detection sensitivity is limited, can’t response so weak signal or extract the photon nature of echo signal. Based on four way of Gm-APD photon polarization detection system using Gm – APD can realize the photon magnitude of polarization detection signal strength. It has the vital significance of small target detection and recognition at a distance. Because the signal strength level has reached the single photon, the surroundings and the noise of the system will greatly affect the precision of detection, this paper mainly analyzes the factors that influence the system precision and improve detection precision of the method is given.At first, this paper researches present situation of the photon polarization detection and analyzes the photon polarization research progress in the field of quantum communication in order to determine the research content of this article. Photon polarization using quantum description and photons through of optical element are given. We establish quantum stokes parameters and the relationship between the classical stokes parameter. Four-way photon polarization detection system are analyzed and photon polarization algorithm is given. Scaling in the detection system and preliminary experiments, experiments prove the feasibility of numerical algorithms and calibration algorithm.Secondly we analyzes by non-ideal device effects on detection accuracy and mainly analyses the insufficient NPBS, wave plate dichroism. The results show that beam splitter spectral inequality and polarization sensitive influence the detecting result. Beam splitter model is set up for this phenomenon, and restoration algorithm is given. The results show that the algorithm can effectively decrease the error of polarization detection.Finally semaphore system is analyzed and under the condition of single photon optical element model is established, and obtaining the relationship between semaphore and the detection accuracy. The simulation results show that when the signal is larger than 1000, The detection precision can meet the requirements. The fiber coupling efficiency and quantum efficiency of probe is can lead to larger detection error. We analyze the influence of shot noise of noise on the detection accuracy, designing the photon polarization detection system based on vacuum injection system. The results show that the vacuum injection can effectively reduce the error of stokes parameters so as to improve detection precision.