基于一种新型抽运耦合技术的光纤激光放大器

High-Power Fiber Laser Amplifiers Based on a New Pump-Coupling Technology

通过建立耦合模方程,对一种同时包含传输芯和增益芯的复合结构光纤中的模场耦合特性进行了理论分析,同时使用速率方程和热传导方程对基于这种复合结构光纤的激光放大器的增益特性和热分布进行了数值计算和分析。研究结果表明,复合结构光纤中抽运光的耦合特性与抽运光的模式、纤芯半径和纤芯距离等因素有关;与端面抽运光纤激光放大器相比,这种复合结构光纤放大器对抽运光的吸收和激光转换相对平缓,光纤具有相对低的温度分布。因此,基于这种复合结构光纤的新型抽运技术可以解决使用端面抽运技术进行抽运时增益光纤温度过高的问题。这种复合结构光纤用于研制大功率光纤激光(放大)器有很大的优越性,为研制超大功率光纤激光(放大)器提供了一种新的途径。

By constructing the coupled-mode equations,the mode-coupling characteristics between the passive and active cores within a kind of composite structural fiber（CSF） are studied theoretically.By using the steady-state rate equations and the heat conductive equations,the gain characteristics and the temperature distribution of all-fiber laser amplifiers based on CSF are calculated and analyzed numerically.The results show that the mode-coupling characteristics depend on the coupled modes,the radius and the separation of the two cores of the CSF.Compared with the end-pumped fiber laser amplifiers,the amplifiers based on CSF have a slow pump light absorption and conversion,and thus,have low temperature distribution.This kind of new coupling-pump technology by using CSF is of apparent advantages.It can be used to solve the problem of high temperature of end-pumped fiber amplifiers,and thereby provides a new approach to design higher power fiber lasers and fiber amplifiers.