基于反射法的光纤位移 振动传感器优化设计

采用非相干光作为光源，以平面镜为反射面，对光纤位移 振动传感器的性能进行研究。推导出光纤输出功率与测量距离的解析表达式,并详细探讨了不同光纤半径、光纤数值孔径、发射光纤和接收光纤间距、发射光纤和接收光纤轴线夹角下输出功率比与测量距离之间的内禀关系。仿真结果表明:光纤半径越小，光纤间距越大，可以测试的距离范围越小；光纤数值孔径、光纤轴线夹角越小，可以测试的距离范围越小。通过分析不同情况下，输出功率比随测量距离变化的关系，可以在实际工程应用中根据测量需要选择设计合适的传感器。此外，还对测量误差进行了分析，得到光纤轴线夹角越小，测量距离的范围越大，误差率越小，当光纤轴线夹角为0.25时，误差率约为1%。

Optimized design of optical fiber displacement vibration sensor based on reflection method

An optical fiber displacement vibration sensor using the incoherent light as a light source and the mirror as a reflective surface was analyzed. The analytic expressions of the optical fiber output power and the measurement distance were derived.The relationship between power ratio and measurement distance was detailedly investigated based on different optical fiber radii, different numerical apertures, different spacings and included angles between transmitting and receiving optical fibers.The results of numerical simulation show that the measurement precision and scope are affected by the optical fiber radius,the optical fiber numerical aperture, the distance and axis angle of both transmitting and receiving optical fibers. By analyzing the variation curves of distance and output power ratio, it is helpful to select the appropriate sensor according to the measurement target in practical engineering applications. Moreover, the measurement error was discussed. The results shows that the measuring range of distance is increased with the increasing of optic fiber included angle, while the error rate is reduced.The error rate is 1% for the included angle of 0.25.