| The squeezed state of the electromagnetic field can be generated in many nonlinear optical processes and is widely used in quantum information processing and quantum metrology.The squeezed states is a significant source of continuous variable quantum information processing.For example,quadrature squeezed vacuum states are applied in implement quantum teleportation,which is one of the most important protocols in quantum information processing.The degree of squeezing is limitation of the fidelity teleportation.Therefore,to obtain high fidelity,it is necessary to improve the squeezing level.In this paper,a quadrature squeezed vacuum state with continuous optical wave is generated by an optical process,and a periodic polarization crystal PPKTP is used as a nonlinear medium for the optical parametric process,and the relative phase between the local light and the squeezing light is locked.The main work is as follows:1.Firstly,the theory of the error signal obtained in the frequency stabilization technique is deduced,and the error signal curve is obtained.Then,based on the PHD frequency stabilization technique,an automatic frequency stabilization device is added to the feedback system and measured.2.The generation process and detection process of the squeezed state of the optical field were deduced,and the advantages and disadvantages of the limitation squeezing enhancement factor and the detection method were analyzed.3.Using a solid state Nd:YVO4/KTP laser as the light source,a vacuum-state light field with a wavelength of 1064 nm and a frequency as low as 1.5 kHz was fabricated using a parametric oscillator(OPO)with dual-wavelength resonance.4.The relative phase of the local light and the signal light is locked by the quantum noise. |
