新型阶跃纤芯微结构包层抗弯曲大模场面积光纤

Novel Bend Resistant Large Mode Area Microstructure Fiber Using Step Index Core

提出一种具有阶跃纤芯和微结构内包层的大模场面积光纤,通过在光纤中引入阶跃纤芯及高折射率棒环形排布的微结构内包层,有效解决传统结构中大模场面积与单模运转的矛盾制约,突破了由弯曲导致光纤弯曲损耗高和弯曲方向角敏感等问题。应用全矢量有限元法结合完美匹配层对光纤特性进行了优化。研究结果表明,在工作波长为2μm、弯曲半径为10 cm时,可以获得高达1 412μm2的模场面积,高阶模与基模损耗比达到767,且对弯曲方向角不敏感。所提出的光纤结构具有大模场面积、优异的单模特性、低的弯曲损耗以及弯曲方向不敏感等显著优势,对推进高功率小型化光纤激光器的发展具有重要意义。

A large mode area fiber with step index core and inner microstructure cladding is proposed.By using step index core and inner microstructure cladding formed by high doped rods with a ring array,the contradictory constraints of large mode field area and single mode in traditional structure can be effectively solved.Furthermore,high bend loss and sensitivity to bend orientation are also eliminated.The optimization of fiber properties are car?ried out by using full-vector finite element model with perfectly matched layer.Research results show that large mode area reaches up to 1 412μm2 and the loss ratio of high-order mode to fundamental mode is up to 767 at the wavelength of 2μm when the fiber is bent at the bend radius of 10 cm.In addition,fiber properties are independent of bend orientation.Due to its advantage of large mode area,excellent single mode,low bend loss and insensitivity to bend orientation,the proposed fiber is of great significance to promote the development of high power miniatur?ized fiber lasers.