基于传统速度干涉仪(VISAR)和光纤速度干涉仪(AFVISAR)的特点,提出了一种由光纤和光纤耦合器组成的工作波长为532 nm的新型全光纤速度干涉仪(NAFVISAR).该干涉仪采用多模光纤器件构成分离系统,单模光纤器件组成核心部分.由于有两路携带不同信息的光束经不同路径传输到耦合器中,当这两路光束满足干涉条件时,可利用它们的干涉场信息来调解出被测靶的信息,从而区分波面的加减速变化.用该系统进行了Hopkinson森杆一维应力加载下的入射杆端面的速度剖面测试,实测速度最大值为49.36 m/s,与理论速度的最大值50.16 m/s基本符合,实现了全光纤速度干涉仪的实用化.

A new type of all-fiber velocity interferometer(AFVISAR),working at the 532 nm, has been developed which has the advantages of both the traditional velocity interferometer(VISAR) and the AFVISAR.The interferometer consists of only fibers or fiber coupled components and has no optical elements such as optic lens or reflectors. It is very compact and easy to operate. Unlike AFVISAR, the laser beam in this new VISAR system arrives at and reflects from the target surface through a multimode fiber component, goes back into and interferences with each other in a [3*3] single-mode fiber coupler. Its working principle was elaborated in this paper. Preliminary experiments using shock Hopkinson bar device show that the new interferometer can successfully probe the velocity profiles of a metal specimen along the axial or radial direction.In addition,the theoretical strike velocity is 50.16 m/s and the velocity measured by the new AFVISAR is 49.36 m/s.