Measurement of distance changes using a fibre-coupled common-path interferometer with mechanical path length modulation
Measurement of distance changes using a fibre-coupled common-path interferometer with mechanical path length modulation
复制标题
使用具有机械路径长度调制的光纤耦合共路径干涉仪测量距离变化
DOI：
10.1088/0957-0233/24/6/065202
复制
发表时间：
2013
影响因子：
2.4
通讯作者：
P. Lehmann
中科院分区：
文献类型：
--
作者：
M. Schulz;P. Lehmann
我们提出了一种新型光纤耦合干涉传感器。微型光学探头充当共光路干涉仪，将激光二极管发射的测量光聚焦到所研究的表面上。探头安装在弯曲梁上，并通过压电致动器周期性偏转。这会产生相位调制干涉信号，该信号由光电二极管转换为电信号。测量原理基于探头与测量对象之间的距离变化导致被测信号发生特征相移的事实。以不同的方式分析光电二极管信号，以实现纳米范围内的高精度和高测量速度，其中传感器的数据速率最终受到所用模数转换器的转换速率的限制。为了扩大传感器的明确范围并提高测量的鲁棒性，我们应用了双波长技术，使用两个同时发射不同波长的激光二极管。重复性测量、对距离变化的响应以及最终具有明确表面轮廓的校准样本的测量证明了系统的性能。
We present a novel type of fibre-coupled interferometric sensor. A micro-optical probe acts as a common-path interferometer and focuses the measuring light emitted by a laser diode onto the surface under investigation. The probe is mounted on a bending beam and deflected periodically by a piezoelectric actuator. This generates a phase-modulated interference signal, which is transformed to an electrical signal by a photo diode. The measurement principle is based on the fact that a distance change between the probe and the measurement object leads to a characteristic phase-shift of the measured signal. The photo diode signal is analysed in different ways in order to enable both high accuracy in the nanometre range and high measurement speeds, where the data rate of the sensor is finally limited by the conversion rate of the used analogue-to-digital converter. In order to extend the range of unambiguity of the sensor and to improve the robustness of measurement, we apply a dual-wavelength technique using two laser diodes emitting at different wavelengths simultaneously. Repeatability measurements, responses to distance changes and, finally, the measurement of calibration specimens with well-defined surface profiles demonstrate the performance of the system.