Wang Xiaoyan, Kondo Mitsuki, Ito Ayumi, Hanawa Masanori
Opt Lett. 2023 Dec 15;48(24):6512-6515. doi: 10.1364/OL.509587.
We have introduced a nanometer-scale non-contact displacement sensing method that relies on phase-diversity optical digital coherent detection. In our prior work, we used a conventional setup involving a 90°optical hybrid, two balanced amplified photodetectors (BAPs), and a narrow-linewidth (NLW) laser, which is complex and costly. However, in this paper, we have streamlined the system configuration by employing alternating quadrature phase modulation (AQPM) reference light, implemented using a phase modulator and a BAP. Moreover, we've employed an economical distributed feedback (DFB) laser, enabling us to achieve displacement sensing at 1.6 nm with a resolution of 0.6 nm. It is notable that there is some degradation in the performance due to the phase noise compared to the NLW laser, which achieves a displacement sensing down to 0.6 nm with a 0.2 nm resolution. Nevertheless, the DFB-AQPM system holds a significant potential for cost-effective, high-resolution nanometer-scale sensing applications.
我们引入了一种基于相位分集光学数字相干检测的纳米级非接触位移传感方法。在我们之前的工作中，我们使用了一种传统装置，该装置包括一个90°光学混合器、两个平衡放大光电探测器（BAP）和一个窄线宽（NLW）激光器，这种装置复杂且成本高昂。然而，在本文中，我们通过采用交替正交相位调制（AQPM）参考光简化了系统配置，该参考光由一个相位调制器和一个BAP实现。此外，我们采用了一种经济的分布反馈（DFB）激光器，使我们能够实现1.6 nm的位移传感，分辨率为0.6 nm。值得注意的是，与NLW激光器相比，由于相位噪声，性能存在一定程度的下降，NLW激光器可实现低至0.6 nm的位移传感，分辨率为0.2 nm。尽管如此，DFB - AQPM系统在具有成本效益的高分辨率纳米级传感应用中具有巨大潜力。
