正弦调制自混合型半导体激光器光学传感的研究

Studies on Sinusoidal Modulated Self mixing Laser Diode for Optical Sensor

研究正弦电流直接调制下 ,单纵模半导体激光器在外部物体的反馈作用时产生的自混合效应 ,利用这种自混合效应 ,对静止物体的距离进行非接触性的测量 .通过设定一参考距离 ,比较靶体与基准点处的拍频信号的最大频率值 ,简化了测量步骤 .分析测量误差与调制电流大小的关系 ,进而确定短距离测距的最佳实验条件 .

This paper covers the theoretical and experimental analysis on self mixing effect, which is caused by the self mixing between the light inside the cavity and the light reflected from an external diffused target, in a single longitudinal mode diode laser modulated with sinusoidal waves. The distance measurement by sinusoidal modulated self mixing laser diode is simplified by using a certain distance as a reference point. The distance is obtained by comparing the maximum frequency of the beat signal to the frequency at the reference point. The measurement error is found to decrease with the increase of the modulation current and this relation is applied to finding the optimum experimental condition for the short distance measurement.