Q型腔自混合散斑实时速度测量

研究基于Q型腔的自混合散斑速度实时传感。利用掺铒光纤、耦合器、波分复用器等组建激光散斑速度传感系统,理论分析动态物体散射光反馈进入激光腔内与原光混合产生的自混合散斑现象,推导出Q型腔输出功率的表达式。以一圆形铝盘为速度传感对象,开发LabVIEW程序对散斑信号进行实时波形采集、滤波去噪及数值计算,得出自混合散斑信号能量密度与物体速率之间的线性关系。基于此关系,对该铝盘侧面的线速率进行实时测量,在175～456mm/s速率范围内可获得较好的测量结果。研究表明,Q型腔内自混合激光散斑的能量密度测速方法,可用于粗糙表面物体的实时速度传感。

Real time velocity tracing of self-mixing speckle in Q-resonator

Real time velocity tracing based on self-mixing speckle in a Q-type fiber resonator was proposed.The measurement system of self-mixing speckle was mainly built up by an erbium-doped fiber(EDF),a partially reflecting optical fiber grating(FBG),and a wavelength division multiplexing(WDM).Self-mixing speckle was produced by part of light backscattered from a moving object mixing with the original one in the Q cavity.The expression of the laser output power was also deduced theoretically.A round rotating aluminum plate was set as the measured target,whose velocity was controlled by a stepping motor.The LabVIEW program was developed to real-time process the speckle signals on waveform acquisition,noise reducing and date calculations.A linear relationship between the energy density of speckle signals and the velocity of the moving object was obtained.Based on the relationship,the line velocity at the side of the round aluminum plate was detected in real time in the range of velocity 175~456 mm/s.Our study showed that the all-fiber system for velocity measurement based on self-mixing speckle in a Q-ring cavity could be used for the measurement of a dynamic rough surface instantaneously.