An Ultrasensitive Long-Period Fiber Grating-Based Refractive Index Sensor with Long Wavelengths. - Qiu-Shun Li; Xu-Lin Zhang; Jian-Guo Shi; Dong Xiang; Lan Zheng; Yan Yang; Jun-Hui Yang; Dong Feng; Wen-Fei Dong (Sensors, 2016)