Physical Review A, 111, 042629 (2025)

Optical phase estimation via homodyne measurement in the presence of photodetector saturation

 Li Jialin¹, Niu Yazhi¹, Qin Lupei^1,*and Li Xin-Qi^2,3,*

1 Center for Joint Quantum Studies and Department of Physics, School of Science, Tianjin University, Tianjin 300072, China.

2 Research Center for Quantum Physics and Technologies, Inner Mongolia University, Hohhot 010021, China.

3 School of Physical Science and Technology, Inner Mongolia University, Hohhot 010021, China.

* qinlupei@tju.edu.cn, xinqi.li@imu.edu.cn

Abstract

For optical phase estimation via homodyne measurement, we generalize the theory from detector's linear to nonlinear response regime, which accounts for the presence of saturation effect. For optical coherent light, we carry out analytic expressions for detector's current and estimate precision. Using specific device parameters, we illustrate the improved estimation after accounting for the saturation effect.