光纤相移点衍射干涉仪关键技术

Key technology for fiber phase-shifting point diffraction interferometer

为了实现光学系统波像差的高精度检测,引入了改进的光纤相移点衍射干涉仪,介绍了其工作原理,并对干涉仪的关键部件包括激光光源及光纤的参数进行了选择和分析。经测试,激光光源功率稳定性约为1%(10 min),光斑尺寸在实现最佳耦合效率允许范围内,光束位置稳定度约为6μm,相干长度为1 cm左右,都在测试精度允许范围内;选择了纤芯直径为3.5μm的单模不保偏光纤,对光纤端面镀半反半透金属膜,实现了较高的条纹对比度和光能利用率,并设计了波前参考源,方便了光纤端面的抛光、镀膜及装卡。最后,利用选择的部件搭建了光纤相移点衍射干涉仪实验装置,为最终能够实现光学系统波像差的高精度检测提供了前期的准备。

In order to measure the wavefront aberration of optical system with the high accuracy, the improved fiber phase-shifting point diffraction interferometer was introduced, its working principle was introduced, and the parameters of the key components of the interferometer including laser source and fiber were selected and analyzed. After the test, the laser power stability was about 1%（10 min）, the spot size was in the allowable range of the optimum coupling efficiency, the beam position stability was about 6 μm, the coherence length was about 1 cm, the above were all in the allowable range of testing accuracy; No polarization-maintaining single-mode fiber was selected, its core diameter was 3.5μm, the fiber endface was coated transflective metal film, the high fringe contrast and light energy utilization were realized, and the wavefront reference source was designed, it＆#39;s convenient for the polishing, coating and clamping of fiber endface. Finally, the selected components were used to build experimental device of fiber phase-shifting point diffraction interferometer, above works provide preparation for ultimately achieving high accuracy test of the wavefront aberration of optical system.