提出了一种新型的双包层光纤激光器侧面耦合技术——梯形微棱镜侧面耦合技术, 能高效且方便地将激光二极管, 特别是高功率激光二极管阵列抽运光耦合进双包层光纤中。该技术采用一个与双包层光纤内包层折射率相同的材料加工而成的具有特殊角度的梯形棱柱, 其中一个表面镀以特定角度的高反射率光学薄膜, 通过梯形微棱镜该镀膜表面的反射, 将抽运光耦合到内包层中。详细阐述了微棱镜反射式耦合技术的基本原理和具体使用方法, 理论计算所得耦合效率超过90 %。通过计算对激光二极管抽运源的线宽、发散角以及梯形微棱镜的具体参数进行了分析, 并对该技术的适用范围, 包括激光二极管、尾纤输出的激光二极管、激光二极管阵列、各种形状内包层结构等做了进一步讨论。

We describe a new method for side pumping of double-clad fiber lasers through trapezoidal micro-prism, which can pump the light sources from laser diodes, especially laser diode arrays, into double-clad fibers easily and effectively. We use a unique-designed trapezoidal micro-prism with the same refractive index as the inner cladding of double-clad fiber. The pump light can be coupled into the inner cladding of double-clad fiber via reflection of the coated side of the trapezoidal micro-prism. Advantages of this technique include no destruction of inner-cladding, high pumping efficiency, simplicity, low cost, easy industrialization and so on. The mechanism and the application method is first introduced and the theoretical coupling efficiency was given (up to 90 %). We analyze the parameters of the trapezoidal micro-prism and the light sources including line width, angle of divergence, etc.. Then we make a further discussion of its applied areas including laser diode, pigtailed laser diode, laser diode arrays, different shape of inner cladding, etc.