大纤芯红外带隙型光子晶体光纤研究

针对一般红外光纤存在材料损耗高、制备工艺复杂、传输性能和输出光束质量差等问题,提出了一种适合CO2(二氧化碳)激光传输的新型大纤芯红外PBG-PCF(光子带隙型光子晶体光纤),该光纤由三角形结构光子晶体在中心抽掉19根毛细管空气孔形成大纤芯。利用PWM(平面波展开法)分析得到了传输波长为10.6μm的CO2激光的光纤带隙图;再利用基于全矢量有限元法的仿真软件COMSOL Multiphysics分析其损耗特性。结果表明,这种结构的PBG-PCF与现有的红外光纤相比,传输10.6μm CO2激光时的损耗更小,约为0.08dB/km,可满足医用传输大功率CO2激光的需要。

Study on large core bandgap infrared photonic crystal fibers

In view of such disadvantages as high material loss, complexity of preparation processes, and poor transmission performances and output beam qualities in ordinary infrared fibers, a new type of large core infrared Photonic Band Gap Photonic Crystal Fiber (PBG-PCF) is presented, which is appropriate for CO2 laser transmission. The large core of such a fiber is produced by removing 19 capillary air holes from the center of photonic crystals with triangular lattice. A fiber bandgap figure of CO2 laser at a transmission wavelength of 10.6 μm is first obtained by PWM analysis and then, its loss characteristics are analyzed by using the simulation software COMSOL Multiphysics based on the full vector finite element method. The results show that the new photonic crystal fiber has smaller loss, about 0.08dB/km, in 10.6 μm CO2 laser transmission than the existing infrared fibers, satisfying the needs of high power CO2 laser transmissions for medical applications.