This research focuses on advanced noise suppression techniques for high-precision measurement systems, particularly addressing the limitations of classical noise reduction approaches. The noise level of laser sources is a crucial factor that directly impacts measurement sensitivity in applications such as gravitational wave detection and biomedical imaging. Classical feedback control techniques have been effective but often hit a bottleneck defined by the classical noise suppression limits. To overcome these challenges, this study proposes a novel method integrating quantum squeezed light with classical feedback control systems to achieve enhanced intensity noise reduction. By employing an amplitude-squeezed light field, a quantum-enhanced feedback control model is developed, theoretically examining the impact of both the feedback loop gain and the degree of squeezing on the noise suppression performance. The results show that the injection of squeezed light significantly reduces the intensity noise, approaching the shot noise limit (SNL), thereby improving the system's sensitivity beyond the classical noise reduction boundaries. Specifically, -10 dB squeezed state injection into the feedback system yielded an additional noise suppression of approximately 8.97 dB, surpassing what is achievable using classical feedback alone. This demonstrates the potential of the proposed approach for pushing measurement precision closer to the quantum noise limits without increasing the laser power.The analysis highlights the asymmetric noise suppression effects between the inner and outer feedback loops. While the outer loop benefits significantly from the squeezed light injection, achieving noise levels unattainable by classical feedback methods, the inner loop shows comparatively minor improvements. This asymmetry is attributed to the inherent characteristics of quantum squeezing and the limitations of the feedback loop design. Further investigation into the individual noise components reveals that the primary contributors to the intensity noise include input noise, photodetector noise, and beam splitter-induced vacuum fluctuations. The injection of squeezed light effectively mitigates these vacuum fluctuations, typically a major noise source in high-precision laser systems. Theoretical research results show that the use of squeezed light in feedback control systems can effectively enhance noise suppression equivalent to a tenfold increase in detected optical power, without the physical drawbacks of increasing laser power such as thermal noise. In conclusion, this study provides a theoretical validation of combining quantum squeezed states with classical feedback control to exceed classical noise suppression limits. The integration of a -10 dB squeezed state demonstrated significant noise reduction, showing that this hybrid approach could revolutionize noise management in precision measurement applications. The results pave the way for further exploration of quantum-enhanced control techniques in fields such as gravitational wave detection, quantum communication, and advanced optical sensing, offering a pathway to improved sensitivity and noise suppression without additional power requirements.
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