相干反馈增强型Sagnac光纤干涉仪量子Fisher信息的研究

Research on quantum Fisher information of Sagnac fiber interferometer enhanced by coherent feedback

摘要:

本文探讨了相干反馈增强型Sagnac光纤干涉仪在不同条件下的量子Fisher信息(QFI)。通过构建理论模型并结合数值仿真,分析了不同反馈结构、增益系数以及量子态输入对干涉仪QFI的影响。研究表明,在合适的反馈强度组合下,双反馈设计的干涉仪能够通过多维度的反馈调节机制,实现优于单反馈结构的最大QFI。但是,相较于单反馈设计,双反馈设计在反馈强度调校的精确性方面要求更为苛刻。当输入量子态为压缩态时,QFI此时受到相位因子和压缩度的共同影响,需对二者进行协同优化才能实现更大的QFI。此外,无论是单反馈还是双反馈干涉仪,其量子Cramér-Rao极限在较宽的反馈强度范围内均能超越标准量子极限,在部分反馈强度处距达到海森堡极限有较小幅度提升。该研究不仅为量子增强型Sagnac干涉仪的设计和参数优化提供理论基础,还为量子精密测量技术的未来发展提供了新的技术路径和应用前景。

Abstract:

This paper explores the quantum fisher information (QFI) of a coherent feedback-enhanced Sagnac fiber interferometer under various conditions. By constructing a theoretical model and combining numerical simulations, the influences of different feedback structures, gain coefficients, and input quantum states on the QFI of the interferometer are analyzed. The results show that under the appropriate combination of feedback intensity, the interferometer designed with double feedback can achieve the maximum QFI better than the single feedback structure through the multi-dimensional feedback adjustment mechanism.However, compared to the single-feedback structure, the dual-feedback design requires more precise adjustment of feedback intensity. When the input quantum state is a squeezed state, the QFI is jointly affected by the phase factor and the degree of squeezing, and both need to be optimized simultaneously to achieve a larger QFI. Additionally, both single-feedback and dual-feedback interferometers can exceed the standard quantum limit and approach the Heisenberg limit with a small margin in a wide range of feedback intensities. This study not only provides a theoretical basis for the design and parameter optimization of quantum-enhanced Sagnac interferometers but also offers new technical paths and application prospects for the future development of quantum precision measurement technology.