1. i3N & Physics Department, University of Aveiro, 3810-193 Aveiro, Portugal
2. Mechanical Department and Graduate Program in Electrical Engineering, Federal University of Espírito Santo, Espírito Santo 29075-910, Brazil
3. Shandong Key Laboratory of Optical Communication Science and Technology, School of Physics Science and Information Technology, Liaocheng University, Liaocheng 252059, China