现在高功率光纤激光器和光纤放大器采用的双包层掺杂光纤, 相对于从半导体泵浦激光器发射出的多模泵浦光束的大发散角, 其内包层的直径很小, 因此把泵浦光有效地耦合到双包层掺杂光纤的内包层是一个急需解决的难题。研制一种熔锥型侧面泵浦耦合器, 可以大幅度提高泵浦光功率, 实现增益光纤的多点泵浦, 在双包层光纤放大器中使用良好, 安全稳定, 实现了较高的耦合效率, 达到了70%, 信号光通过率98%, 信号输入与泵浦输入的隔离度大于50 dB, 泵浦输入对输出端反向传输光的隔离度27 dB。通过对比结构紧凑性、耦合效率、系统稳定性等相关指标发现, 熔锥型侧面泵浦耦合器完全可以满足高功率光纤激光器和光纤放大器的使用要求。

Double-clad doped optical fiber is used in high-power fiber lasers and fiber amplifiers. Compared to the large divergence angle of the multimode pump beam emitted by the semiconductor pump laser, its inner cladding diameter is small, which makes effectively coupling pump beam to the inner cladding of the double-clad doped optical fiber difficult. A kind of fused side-pumped coupler is developed, which enhances the pump power and realizes multi-point pump to the gain fiber. It is used in the double-clad fiber amplifier. It has good security and stability, a coupling efficiency of 70%, a ratio of 98% coupled signal light, and over 50dB isolation of the signal input and pump beam input, and 27dB isolation of the pump beam to the counter -propagation beam are achieved. The fused biconical taper side-pumped coupler has compact structure, good coupling efficiency and system stability, which meets the requirements of the high power fiber lasers and fiber amplifiers.