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光反馈自混合干涉技术是一种新浮现的有别于传统双光束干涉的一类新的测试技术。为了在适度光反馈下进行振动的精密测量,提出了一种基于适度光反馈自混合干涉技术的振动测量方法。经对光反馈自混合干涉信号条纹分析,发现通过选定合适的光反馈水平及激光器线宽展宽因数,可以得到锯齿干涉条纹。这种干涉信号不仅包含振动幅度信息也包含振动方向信息。该振动测量方法利用锯齿干涉条纹的特点,首先通过条纹记数实现大范围振幅粗测,具有半波长位移分辨力;然后基于适度光反馈下小数条纹的特点,给出了小于半波长位移测量的线性表达式,从而实现位移的精测。仿真计算表明,该方法可以实现大量程高分辨力振动位移测量,在叠加20 dB的噪声下,振幅测量相对误差平均为0.5%。
Optical feedback self-mixing interference technique is a new kind of new testing technique which is different from the traditional two-beam interference. In order to measure the vibration accurately with light feedback, a vibration measurement method based on adaptive optical feedback self-mixing interference technique is proposed. By analyzing the fringe pattern of self-mixing interference signal of optical feedback, we found that sawtooth interference fringes can be obtained by selecting suitable optical feedback level and laser linewidth broadening factor. This interference signal contains not only vibration amplitude information but also vibration direction information. The vibration measurement method utilizes the characteristics of sawtooth interference fringes. Firstly, a large-amplitude amplitude measurement is performed by using fringe counts, and the half-wavelength displacement resolution is obtained. Then, based on the characteristics of the decimal fringes under moderate light feedback, Linear expression, in order to achieve precision displacement measurement. Simulation results show that this method can measure vibration displacement with high resolution and large range, and the relative error of amplitude measurement is 0.5% on average with 20 dB noise superimposed.