摘要
为了获得大模场光纤结构以提升光纤激光的输出功率,通常采取多种技术措施来增加光纤的模场大小。但随着光纤模场大小的增加,光纤波导对模场的约束能力下降,导致模场大小的提升受到限制。从光纤波导的本征模场理论出发,首先分析大模场光纤模场分布的特点,然后讨论模式耦合和模场畸变现象对模场大小增长的限制作用。最后,在考虑限制因素影响的基础上,应用有限元分析方法对几种折射率分布的光纤模场进行计算。结果表明,光纤模场的等效面积与相邻模式之间的等效折射率平方差的乘积趋向一个常量,光纤模场大小的增长受到这一常量的约束。
In order to obtain a large-mode-area fiber structure to improve fiber lasers′ output power,several technical measures have been adopted to scale the fiber mode field size.However,with the mode field size increasing,the fiber waveguide′s ability to confine the mode field declines,which limits the growth of the mode field size.Based on the fiber eigen-mode field theory,the mode field distributions of the large-mode-area fibers are discussed,and the limitation effects of the mode field size growth imposed by mode coupling and mode distortion are analyzed.Considering the impact of the limitations,the mode field distributions of several refractive index fibers are calculated by using the finite element method.The mumerical results show that the product of the equivalent mode area and the square difference of the effective refractive index between two adjacent modes tends to a constant,which constrains the scalability of the fiber mode field.
出处
《激光与光电子学进展》
CSCD
北大核心
2010年第12期16-20,共5页
Laser & Optoelectronics Progress
关键词
光纤激光器
大模场光纤
模场大小
模场畸变
模式耦合
fiber lasers
large-mode-area fiber
mode field size
mode distortion
mode coupling
