高功率光纤振荡器因性能稳定、便携性好、成本低等优点,受到广泛关注。2016年,国防科学技术大学利用自主研发的分布式侧面耦合包层抽运光纤,实现了多级级联分布式侧面抽运光纤振荡器2kW量级的功率输出,并通过引入末级反向抽运方案,实现了对输出端残余抽运光的良好抑制。实验装置示意图如图1(a)所示。该激光器为一个全光纤振荡器,振荡器增益光纤由三段长度分别为10,10,5m的分布式侧面耦合包层抽运光纤级联而成,信号纤芯、信号光纤内包层、抽运光纤的直径分别为25,250,250μm。振荡器采用末级 High-power optical fiber oscillator due to stable performance, portability, low cost, has attracted widespread attention. In 2016, the National University of Defense Technology used a distributed laterally coupled cladding pumped optical fiber to realize the power output of 2kW in cascaded distributed side-pumped optical fiber oscillators. By introducing the reverse pumping The solution is to achieve a good rejection of the residual pump light at the output. Experimental device diagram shown in Figure 1 (a) below. The laser is an all-fiber oscillator. The gain fiber of the oscillator is made up of three sections of distributed side-coupled clad pumped fiber cascades with lengths of 10, 10 and 5 m respectively. The signal fiber core, the signal optical fiber inner cladding, Optical fibers have diameters of 25, 250 and 250 μm, respectively. Oscillator using the last level