Han Junlong, Liu Exian, Liu Jianjun
J Opt Soc Am A Opt Image Sci Vis. 2019 Apr 1;36(4):533-539. doi: 10.1364/JOSAA.36.000533.
In this paper, a silica-based sixfold circular gradient-diameter photonic crystal fiber (CGPCF) with five rings is proposed, and the matching conditions of air hole lattices are established considering the gradient and diameter of the air holes. This CGPCF supports endlessly single-mode propagation due to the existence of small air holes near to the fiber core based on the matching rule. Simultaneously, it exhibits an ultralarge effective mode area of 3110 μm in the straight case and 1105 μm in the bending case with a bending radius of 15 cm at the wavelength of 1550 nm. In addition, within an ultrawide communication wavelength range from 1000 to 2000 nm (from 1350 nm to 2000 nm), the effective mode area in the straight (bending) case still maintains more than 3043 μm (981 μm), and the bending loss maintains an ultralow order of magnitude of 10 dB/m at a great degree of bending radius of 15 cm. Moreover, the rotation-symmetric structure of CGPCF can reduce the impact of bending orientation on the optical properties. The proposed CGPCF is highly meaningful for optical fiber communication, high-power laser systems, and optical amplifiers.
本文提出了一种具有五个环的基于二氧化硅的六重圆形梯度直径光子晶体光纤（CGPCF），并考虑气孔的梯度和直径建立了气孔晶格的匹配条件。基于匹配规则，由于在光纤纤芯附近存在小气孔，这种CGPCF支持无限单模传输。同时，在波长为1550nm时，它在直的情况下表现出3110μm²的超大有效模面积，在弯曲半径为15cm的弯曲情况下表现出1105μm²的超大有效模面积。此外，在1000至2000nm（从1350nm至2000nm）的超宽通信波长范围内，直（弯）情况下的有效模面积仍保持在3043μm²（981μm²）以上，并且在15cm的大弯曲半径下弯曲损耗保持在10⁻⁶dB/m的超低量级。此外，CGPCF的旋转对称结构可以减少弯曲方向对光学特性的影响。所提出的CGPCF对光纤通信、高功率激光系统和光放大器具有重要意义。
