新型长距离无导轨激光干涉仪

A Novel Non-guideway Laser Interferometer for Absolute Long Distance Measurement

外腔半导体激光的线宽小于100kHz，干涉相干距约为1000m，波长可调节范围超过100nm（1495—1645nm），应用上述二项特性，通过改变波长（频率）测得任意点到仪器的距离（不需要在测量计数时移动反光镜）。其测量距离大于100m，分辨率可以优于3nm，不确定度可以达到2．5×10^-6L，达到工程测量对测长仪器的要求。为提高测量不确定度，还可以使用2个或2个以上特定波长，通过小数重合法，更精确测得与被测点的距离，不确定度可以达到5×10^-7L。其优点是：测量时无需导轨移动测量镜（对比双频激光干涉仪）、可以挡光进行间断测量（对比激光跟踪仪）、测量不确定度和分辨率精度指标高（对比激光测距仪）。可以为尺寸大、形状复杂的几何物件和大型建筑物、基线场等精密测量提供十分有效的方法和工具。

A novel non-guideway laser interferometer for absolute long distance measurement is presented . An external cavity diode laser （ECDL） shows great selectivity to its wavelength, with a bandwidth less than 100 kHz and a coherent distance of about 1000 m. The wavelength can be continuously tuned from 1495 nm to 1645 nm. These two characteristics enable a wavelength-tun- ing interferometry for absolute long distance measurement. In the iuterferometry for measuring the distance of L, the resolution and uncertainty could be 3 nm and 2.5 × 10^-6L respectively, when the measuring range is about 100 m. In order to improve accura- cy, exact fraction method can be applied employing several specific wavelengths. By this means, the uncertainty could be up to 5 × 10^-7L.