Theoretical And Experimental Studies On Quantum Enhanced Precision Measurement Realized By Nonlinear Interferometer

Using non-classical properties of quantum state,precision measurements systems have achieved better sensitivity beyond classical limits,providing new momentum to the development of modern science and technologies.Being one kind of detection loss in-sensitive quantum dense metrology scheme,nonlinear interferometer can achieve quan-tum enhanced sensitivity by utilizing entanglement resources and have attracted much attention in these years.Nonlinear interferometer configured in single beam sensing condition can achieve simultaneous multi-parameter measurement,while those config-ured in dual-beam sensing can realize coherently boosted phase sensing.The capability to redistribute quantum resource make the nonlinear interferometers versatile in dif-ferent applications.Besides,the quality of entangled state limits the performance of nonlinear interferometer,thus studying the output property of optical parametric ampli-fier that generated the entangled state is also important for the improvement of nonlinear interferometer.The major contents and innovation points of this article are:(i)Analyzed the quantum enhanced multi-parameter measurement property of sin-gle beam sensing nonlinear interferometer.With the help of joint measurement system,we observed 1 d B improvement on signal SNR at arbitrary quadratures simultaneously,together with demonstration of its detection loss tolerant property.(ii)Analyzed the coherently boosted phase measurement property of dual-beam sensing nonlinear interferometer.Using dual-beam sensing nonlinear interferometer,which redistribute the quantum resource to face signal measurement,the SNR of phase signal is improved by 3.9 d B.This result also reveals the quantum information splitting property of the second parametric amplifier.(iii)Improved the measurement of entangled state generated by fiber optical para-metric amplifier.Using direct detection method,the inseparability of entangled state is improved to I_FOPA=0.52,lower than shot noise limit by 2.8 d B.With the help of parametric amplifier assisted entanglement measurement,the inseparability measure-ment result is further improved to I^?_FOPA=0.34,lower than shot noise limit by 4.6d B.To avoid temporal mode matching problem,we measured the intensity difference squeezing state generated by fiber parametric amplifier and the result is 6.11 dB for intensity difference squeezing degree.These results indicate great potential for nonlin-ear interferometers used for precision measurement and provide a reference for further optimizations and applications.