论文部分内容阅读
近年来，由于信息技术、微电子机械系统等领域的迅速发展，对精密测量的要求越来越高。激光干涉测量具有灵敏度高、非接触性等优点，它的测量精度由于光外差技术的引入大大提高。半导体激光（LD）不仅体积小，价格低，用电省，而且波长调制简便，因而成为大多数外差干涉仪的光源。在半导体激光干涉仪中，通过直接调制LD的注入电流可以实现外差技术，但是改变注入电流来调制LD波长的同时，LD的输出光强也被调制，这将影响测量精度。光强被调制对测量的影响通常用软件的方法来补偿，但这种方法有很大的缺点。一是补偿只能是粗略的，另外软件需要根据外界条件的变化随时修正。为从根本上解决直接调制LD波长对测量的影响，本研究提出了一种间接调制激光波长的方法，采用这种方法能把这种光强度变化造成的影响降低到可以忽略的程度。
In recent years, due to the rapid development in the fields of information technology, microelectromechanical systems and the like, demands for precision measurement are getting higher and higher. Laser interferometry with high sensitivity, non-contact, etc., its measurement accuracy due to the introduction of optical heterodyne greatly increased. Semiconductor lasers (LDs) are not only small in size, low in price, power-saving, and easy to modulate in wavelength, making them the light source for most heterodyne interferometers. In the semiconductor laser interferometer, heterodyne technology can be realized by directly modulating the injection current of the LD. However, while changing the injection current to modulate the LD wavelength, the output intensity of the LD is also modulated, which affects the measurement accuracy. The influence of light intensity modulation on the measurement is usually compensated by software methods, but this method has great drawbacks. First, the compensation can only be rough, and the software needs to be amended at any time according to changes in external conditions. In order to fundamentally solve the direct modulation of LD wavelength on the measurement, this study presents a method of indirect modulation of the laser wavelength, the use of this method can reduce the impact of this light intensity to a negligible extent.