光控相控阵雷达天线阵列间的相位关系由光真延时实现,这意味着光纤长度的准确性决定了波束的相位一致性等参数。光真延时制备通常采用光纤切割方法,精度为0. 5 mm。随着现代雷达载频和带宽的提升,光纤加工精度要求为0. 1 mm,甚至更小,目前光纤切割的精度无法高效地满足这一要求。文中研究了基于光纤拉锥的方法制备光延时线以形成波束网络。通过光纤局部的高温加热使光纤处于熔融态,同时电控平移台对光纤进行拉伸。光纤长度的准确性可达10 μm,并且不引入额外插损。该方法有利于提升雷达探测、跟踪等性能。

The phase relationships among antenna arrays are realized by optical true time delay lines in optically controlled phased array radar. It means that the characteristics of radar beam, such as phase uniformity, are decided by fiber lengths. Optical true delay lines are usually fabricated by fiber cutting with 0. 5 mm accuracy. However, with the increase of carrier frequency and bandwidth of modern radar, the accuracy of fiber length should be 0. 1 mm or even less, which could not be efficiently accomplished by normal fiber cutting. In this work, the fabrication of optical delay line based on fiber tapering was studied to form radar beam network. Fiber was fused through heating and the length was stretched by electrical controlled translation motor. In this way, 10 μm accuracy of fiber length could be realized. Furthermore, no extra insert loss is induced in the process. Therefore, the performance of radar could be improved, such as detecting, tracing and so on.

TN958. 92