Experimental study on the evolution of bright-dark pulses in a 2 μm mode-locked thulium/holmium co-doped fiber laser

作     者：Wang Xiaofa Wang Jie Zhao Kunyang 

作者机构：Chongqing Key Laboratory of Photoelectronic Information Sensing and Transmitting Technology， School of Optoelectronic Engineering， Chongqing University of Posts and Telecommunications 

出 版 物：《Optoelectronics Letters》 (光电子快报(英文))

年 卷 期：2024年

学科分类：080901[工学-物理电子学] 0809[工学-电子科学与技术（可授工学、理学学位）] 08[工学] 080401[工学-精密仪器及机械] 0804[工学-仪器科学与技术] 0803[工学-光学工程] 

基　　金：supported by the Natural Science Foundation of Chongqing City China (No.cstc2018jcyjAX0585) 

摘      要：We experimentally demonstrate the effects of pump power and polarization state on the evolution of bright-dark pulses (BDPs) in a figure-eight passively mode-locked thulium/holmium co-doped fiber laser (THDFL) using nonlinear amplifying loop mirror (NALM) technology. As the pump power increases from 0.5 W to 1 W， the BDPs are separated and exhibit a linear increase in the time interval between the bright pulse (BP) and dark pulse (DP)， which roughly corresponds to the reciprocal of the modulation frequency in the radio frequency (RF) spectrum. Additionally， the polarization state in the cavity is altered by adjusting the polarization controller (PC)， the central wavelength of spectrum， pulse waveform， and full width at half maximum (FWHM) of BDPs in different states are presented.