Huang Zheng, Bai Zhiyong, Zhu Guoxuan, Huang Churou, Chen Jiayan, Liu Shen, Fu Cailing, He Jun, Wang Yiping
Opt Express. 2021 Nov 22;29(24):39384-39394. doi: 10.1364/OE.442760.
A class of ultra-short chiral long period fiber gratings (CLPFGs) are prepared by writing a spiral curve on the surface of a six-mode fiber. The CLPFGs are applied to excite ±2- and ±3-order orbital angular momentum (OAM) modes. The coupling efficiency of the CLPFG in these modes can be as high as 99%, when the length is only 0.5cm. The polarization characteristic of the excited higher-order OAM modes in CLPFGs was theoretically analyzed and experimentally investigated. Results show that the obtained ±2- and ±3-order OAM modes are polarization independent, as expected.
