Chen, Siyu, Yuehui Ma, Hang Su, Xiaolong Fan, and Yunqi Liu. “Few-Mode Fiber-Based Long-Period Fiber Gratings: A Review”. Journal of Optics and Photonics Research 1, no. 1 (February 14, 2024): 02–15. Accessed July 3, 2024. https://ojs.bonviewpress.com/index.php/JOPR/article/view/2414.