Theoretical Investigation On Quantum Enhancement Based On Phase Sensitive Optical Parametric Amplification

As Laser technology and nonlinear optics arisen,the optical parametric amplification and the corresponding fields are the projects of international advanced scale and cause wide attention.Phase-sensitive optical parametric amplification in quantum optic and nonlinear optics fields has a unique property of breaking the 3 dB quantum limit of the optical-amplifier noise figure(NF),which is demonstrated by experiments and theories.Therefore,the phase-sensitive amplification has been widely studied in applications of biological microscopy,remote sensing system and laser radar system.In this thesis,phase-sensitive image amplification is theoretically analyzed and numerically simulated.The thesis mainly includes the following sections:(1)First,we derive the equations of motion of the field operators in phase-sensitive and phase-insensitive optical parametric amplification using the Heisenberg equation,the phase mismatch is not ignored.Next,using the solutions of the derived equations,the quantum-mechanical noise figure and gain is evaluated.The results showed that phase-sensitive amplification can break the 3 dB quantum limit of traditional optical amplifier,and can improve the efficiency of nonideal photodetection.(2)We theoretically investigate that the squeezed light can break the shot-noise limit.When the squeezed light is used to the input of phase-sensitive amplification,the output of amplification remains a squeezed light.The squeezed parameter is increased with the gain of phase-sensitive amplification,and the squeezed angle change a little in the larger gain.Meantime,we driver a theoretical model with the image amplification of squeezed light,and the results showed the squeezed light in phase-sensitive amplification is less influenced by the phase mismatch compared the coherent light.(3)We investigate the amplified process of injected squeezed vacuum field in quantum-enhanced LADAR with deriving the theoretical model.The squeezed parameter and the phase angle are introduced to derive the gain of theoretical model.We demonstrate that the loss of gain caused by nonideal PSA can be restored to a negligible extent by adjusting the squeezed angle.Further,the noise spectrum of homodyne detection is obtained at the output of quantum-enhanced LADAR receiver,and the vacuum noise can be obviously suppressed by adjusting the squeezed angle with nonideal PSA.Finally,the simulation results of quantum-enhanced LADAR receiver show that SNR of system is efficiently improved under the condition of nonideal PSA.