Abstract Metrology based on self-mixing interferometry (SMI) covers a wide range of metrical application such as measurement of distance displacement, vibration, velocity, flow and size of Brownian particles. In general, two SMI parameters namely, optical feedback factor C and linewidth enhancement factor (LEF) α are significant in the above-mentioned measurements. Particularly, the joint estimation of C and α is the key to real-time displacement self-mixing (SM) sensor with sub-wavelength resolution. The application of the approach to the immediate estimation of C and α proposed by Kim et al. (2018) is limited to the moderate and strong feedback regime. The paper presents an approach to the immediate estimation of C for the weak feedback regime, to which the approach by Kim et al. (2018) is impossible to be applied, thus allowing the immediate joint estimation method to be applied to all the regimes. Because the proposed method is incomparably simpler than the previous ones and very efficient in hardware, it will be of great assistance to developing a low-cost real-time SM displacement sensor with sub-wavelength resolution in which complex computation such as optimization are impossible. In addition, the paper discusses the effect of C and α on the accuracy of displacement reconstruction.

中文翻译：

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线宽增强因子对位移重构的影响及弱反馈反馈因子的即时估计

摘要 基于自混合干涉测量法 (SMI) 的计量学涵盖了广泛的计量应用，例如距离位移、振动、速度、流量和布朗粒子尺寸的测量。通常，两个 SMI 参数，即光反馈因子 C 和线宽增强因子 (LEF) α 在上述测量中很重要。特别是，C 和 α 的联合估计是具有亚波长分辨率的实时位移自混合 (SM) 传感器的关键。Kim 等人提出的 C 和 α 直接估计方法的应用。(2018) 仅限于中等和强反馈机制。该论文提出了一种针对弱反馈机制立即估计 C 的方法，Kim 等人的方法对此进行了描述。(2018) 不可能被应用，从而允许将立即联合估计方法应用于所有制度。由于所提出的方法比以前的方法简单得多，并且在硬件上非常有效，因此对于开发具有亚波长分辨率的低成本实时SM位移传感器具有很大的帮助，其中不可能进行优化等复杂计算。此外，论文还讨论了C和α对位移重建精度的影响。