Wu Zhenhua, Yi Zhen, Gu Wenju, Sun Lihui, Ficek Zbigniew
School of Physics and Optoelectronic Engineering, Yangtze University, Jingzhou 434023, China.
Quantum Optics and Engineering Division, Institute of Physics, University of Zielona Góra, Szafrana 4a, 65-516 Zielona Góra, Poland.
Entropy (Basel). 2022 Nov 29;24(12):1741. doi: 10.3390/e24121741.
A coherent feedback scheme is used to enhance the degree of squeezing of the output field in a cavity optomechanical system. In the feedback loop, a beam splitter (BS) plays the roles of both a feedback controller and an input-output port. To realize effective enhancement, the output quadrature should take the same form as the input quadrature, and the system should operate at the deamplification situation in the meantime. This can be realized by choosing an appropriate frequency-dependent phase angle for the generalized quadrature. Additionally, both the transmissivity of the BS and the phase factor induced by time delays in the loop affect optical squeezing. For the fixed frequency, the optimal values of transmissivity and phase factor can be used to achieve the enhanced optical squeezing. The effect of optical losses on squeezing is also discussed. Optical squeezing is degraded by the introduced vacuum noise owing to the inefficient transmission in the loop. We show that the enhancement of squeezing is achievable with the parameters of the current experiments.
采用一种相干反馈方案来提高腔光机械系统中输出场的压缩程度。在反馈回路中，一个分束器（BS）同时扮演反馈控制器和输入 - 输出端口的角色。为了实现有效的增强，输出正交分量应与输入正交分量具有相同的形式，并且系统应同时在放大倍数小于1的情况下运行。这可以通过为广义正交分量选择合适的频率相关相位角来实现。此外，分束器的透射率和回路中时间延迟引起的相位因子都会影响光压缩。对于固定频率，可以使用透射率和相位因子的最佳值来实现增强的光压缩。还讨论了光学损耗对压缩的影响。由于回路中的低效传输，引入的真空噪声会使光压缩降低。我们表明，利用当前实验的参数可以实现压缩的增强。
