Accurate displacement-measuring interferometer with wide range using an I2 frequency-stabilized laser diode based on sinusoidal frequency modulation
Accurate displacement-measuring interferometer with wide range using an I2 frequency-stabilized laser diode based on sinusoidal frequency modulation
复制标题
DOI：
10.1088/0957-0233/27/10/105201
复制
发表时间：
2016-08
影响因子：
2.4
通讯作者：
T. Vu;Masato Higuchi;M. Aketagawa
中科院分区：
文献类型：
--
作者：
T. Vu;Masato Higuchi;M. Aketagawa
我们提出了使用正弦频率调制技术，以提高外腔激光二极管（ECLD）的频率稳定性和位移测量干涉仪的测量精度和范围。通过调制注入电流将ECLD的频率调制在300 kHz，并且通过零方法将其锁定到跃迁6-3，P（33），127 I2（633 nm）的b21超精细分量。在100 s采样时间下，相对频率稳定度达到6.5 × 10−11。稳定的ECLD然后被用作非平衡迈克尔逊干涉仪的光源。在干涉仪中，可以使用基于干涉信号的两个连续和象限相位谐波的李萨如图来确定目标反射镜的位移和方向。通常，所提出的方法的干涉仪的测量范围受到调制指数和谐波的信噪比的限制。为了克服这个缺点，选择合适的连续谐波对用于特定的测量范围来测量位移。在特定范围内所提出的方法确定的位移进行了比较与商业电容传感器所观察到的。通过比较可知，该方法具有较高的位移确定精度。通过选择合适的调制指数和合适的连续谐波对，测量范围也扩展到10 m。
We propose the use of the sinusoidal frequency modulation technique to improve both the frequency stability of an external cavity laser diode (ECLD) and the measurement accuracy and range of a displacement-measuring interferometer. The frequency of the ECLD was modulated at 300 kHz by modulating the injection current, and it was locked to the b21 hyperfine component of the transition 6-3, P(33), 127I2 (633 nm) by the null method. A relative frequency stability of 6.5 × 10−11 was achieved at 100 s sampling time. The stabilized ECLD was then utilized as a light source for an unbalanced Michelson interferometer. In the interferometer, the displacement and direction of the target mirror can be determined using a Lissajous diagram based on two consecutive and quadrant-phase harmonics of the interference signal. Generally, the measurement range of the interferometer by the proposed method is limited by the modulation index and the signal-to-noise ratio of the harmonics. To overcome this drawback, suitable consecutive harmonic pairs were selected for the specific measurement ranges to measure the displacement. The displacements determined in the specific ranges by the proposed method were compared with those observed by a commercial capacitive sensor. From the comparison, the proposed method has high precision to determine the displacement. The measurement range was also extended up to 10 m by selecting a suitable modulation index and suitable consecutive pairs of harmonics.