自聚焦棒透镜准直系统的装配误差引起的附加耦合损耗分析

Misalignment induced Excess Loss in Gradient index rod Lens Collimating Systems

一对１／４节距自聚焦棒透镜构成的准直系统通常存在三种装配误差：错位、间隔和倾斜，由此产生一定的附加耦合损耗。理论分析和数值计算结果表明，损耗与装配误差在小范围内近似呈平方递增关系，增幅与透镜聚焦参数有关。根据具体装配工艺选取合适的自聚焦棒透镜，能显著降低耦合损耗。

In a collimating system formed by a pair of quarter pitch gradient index rod (GRIN) lenses, there exist three kinds of assembling misalignments: lateral offset, longitudinal separation and angular tilting. Excess coupling losses so arise. The losses increase quadratically with the misalignment amounts when they are small, depending on the focusing parameter of the GRIN lens. It is possible to reduce the excess losses greatly by choosing an appropriate lens in accordance with the practical assembling conditions.