高精度的干涉仪在精密测量领域有着非常重要的作用。相位估计的不确定度通常用来判定一个干涉仪测量的精密程度，相位估计的不确定度越小意味着相位灵敏度越高。在理论上提出了由光学参量放大器和线性光学分束器（BS）组成的非线性干涉仪。基于热85Rb原子系综四波混频（FWM）过程的光学参量放大器用来实现干涉仪中光束的合成与分离。BS作为反馈控制器，通过控制器件的反射率，来控制FWM过程的出射光返回到入射光端口的比例。与传统干涉仪的相位灵敏度相比，通过理论计算证明了基于光学参量放大器反馈的非线性干涉仪相位灵敏度更高。本研究结果在量子精密测量领域有着潜在的研究价值。

High-precision interferometers play a critical role in the field of metrology. The uncertainty of phase estimation can be used to evaluate the precision of an interferometer. The lower the uncertainty of phase estimation, the higher the phase sensitivity. We theoretically propose a nonlinear interferometer composed of an optical parametric amplifier and a linear optical beam splitter (BS). An optical parametric amplifier based on the hot rubidium-85 atomic ensemble four-wave mixing (FWM) process is used to combine and separate the beams in the interferometer. As a feedback controller, the BS controls the proportion of the output light returning to the input light port in the FWM process by controlling the reflectivity of the device. Through theoretical calculations, it is proved that the phase sensitivity of a nonlinear interferometer based on optical parametric amplifier feedback is enhanced compared with that of traditional interferometers. Our research results are expected to have potential applications in the field of quantum metrology.