一种实现空间光—单模光纤的自动耦合方法

Auto-coupling method for making space light into single-mode fiber

精确定位耦合光斑在光纤端面上的位置是空间光与单模光纤耦合技术的关键。提出由压电陶瓷、控制器、驱动器、光电探测器、耦合透镜及反射镜组成闭环控制系统,使用光栅式扫描初步确定最佳耦合位置后再用五点跟踪法结合一维平动精确定位实现自动耦合。推导出扫描所需步长和时间,详细阐述了光栅式扫描和五点跟踪法原理。实验结果表明,该方法可以在较短时间内根据耦合入光纤的光功率大小自动搜寻到最佳位置,获得59.2%的最大耦合效率,能校正由地表震动、气流扰动等低频干扰造成的数值偏差保持较高的耦合效率。

The sticking point of coupling space light and single-mode fiber is how to find the best position in the transverse plane of fiber precisely, An auto-coupling system was proposed, which mainly consisted of piezoceramics, controller, drivers, coupling lens and reflector. At the beginning, the system used raster scan to confirm the best position cursorily then used five-point tracking arithmetic and one-dimensional motion arithmetic to confirm and keep it accurately. The length of scan step and the time of finishing scan were worked out. Theories of raster scan and five-point tracking arithmetic were expounded. Analysis results of experiment show that the method can make the system search the best position automatically based on the power of the light which is coupled into the single-mode fiber. The optimal coupling efficiency is about 59.2%, which can be obtained in a few minutes by the system. The deviation of numerical value which is caused by low frequency disturbance such as the shake of the earth surface, disturbance of air current can be emendated automatically.