Optical Information Sensing And Its Application Based On Single Photon Detection

Compared with traditional photoelectric detection technology,single photon detection technology has higher detection sensitivity,which can greatly improve the sensing accuracy of optical information.This thesis realizes the sensing of intensity,phase,polarization and other information of light based on single-photon detection,and further apply this sensing technology in the monitoring of optical fiber health status,the feedback control of phase in fiber interferometer,and the feedback control of polarization state of photon propagating in fiber.The main contents in this thesis are as follows:Firstly,the effects of laser and detector parameters on the dynamic range and spatial resolution of Photon Counting Optical Time-Domain Reflectometry(PC-OTDR)are theoretically analyzed,based on establishing a simulation platform of PC-OTDR.With the results in theoretical simulation,an experiment test system of PC-OTDR is established by using single-photon detection in 850 nm wavelength band,gain-switched semiconductor pulsed laser and time-to-digital converter.In this system,a fiber optical time-domain reflectometry with dynamic range of 15.21 d B and spatial resolution of0.045 m has been built.The strong reflection phenomenon in PC-OTDR also is preliminary investigated for the suppression of the adverse effects of strong reflection in the future.Secondly,a systematic analysis of the phase stability of the unbalanced fiber interferometer is implemented,and a proportional-integral-derivative(PID)feedback control method of phase is proposed and demonstrated based on of superconducting nanowire single photon detection.By using weak coherent light with narrow bandwidth as reference light,the phase of an unbalanced fiber Michelson interferometer with arm length difference of ?1 m is stabilized.The jitter of relative phase difference after stabilization is less than 0.042 rad.Based on the stabilized interferometer,single-photon interference is observed and the measured visibility of fringe reaches 99.83±0.02%.Thirdly,in order to overcome the stochastic variation of polarization state of photons after the propagation in single-mode fiber link,an experiment setup for searching and feedback controlling the polarization state is established based on electrical polarization control,polarization beam splitting,and single photon detection.The long-time evolution of polarization state of photons in a 20 km long fiber link are measured in laboratory under the case with and without feedback control.The measurement results show that the feedback control scheme in this thesis can effectively realize the stabilization of polarization state of photons in the above fiber link.