1. Key Laboratory of In-fiber Integrated Optics, Photonics Research Center, College of Physics and Optoelectronic Engineering and the College of Power and Energy Engineering, Harbin Engineering University, Harbin, China
2. College of Power and Energy Engineering, Harbin Engineering University, Harbin, China
3. Photonics Research Center, School of Electronic Engineering and Automation, Guilin University of Electronic Technology, Guilin, China