1.Key Laboratory of Specialty Fiber Optics and Optical Access Networks, Shanghai Institute for Advanced Communication and Data Science, Joint International Research Laboratory of Specialty Fiber Optics and Advanced Communication, Shanghai University, Shanghai 200444, China 2.Aston Institute of Photonic Technologies (AIPT), Aston University, Birmingham B47ET, UK
Fund Project:Project supported by the National Natural Science Foundation of China (Grant Nos. 61975107, 61605107) and the “111” project Ministry of Education of China (Grant No. D20031)
Received Date:10 August 2020
Accepted Date:27 August 2020
Available Online:16 September 2020
Published Online:20 September 2020
Abstract:In this paper, a dissipative soliton mode-locked fiber laser is established based on carbon nanotube in order to study the polarization dynamics of dissipative soliton by using a commercial polarimeter. Under the pump power of 160 mW, stable dissipatives soliton are observed to have a limited cycle polarization trajectory shown on Poincare sphere, indicating the periodic modulation of anisotropy in cavity. The stable dissipative soliton possesses a high signal noise ratio of 57.7 dB at fundamental frequency. Moreover, the fast oscillation of state of polarization leads to a lower degree of polarization (DOP). In addition, the polarization controllers are employed to compensate for the birefringence in the cavity to adjust the ratio between cavity length and birefringence length. As a result, we can observe the polarization evolving from the polarization locked attractor to the limited cycle attractor by adjusting polarization controllers. It is noted that this dynamic polarization trajectory can be manually controlled. By comparing polarization attractor with DOP, it is clear that the size of trajectory shown on Poincare sphere is inversely proportional to DOP. We expect our work to be conducible to studying the physics in lasers and creating a new type of polarization tunable laser. Keywords:fiber laser/ dissipative soliton/ polarization attractor
图 1 基于碳纳米管聚合物薄膜的锁模光纤激光器实验装置
图 2 偏振进动VDS (a) 典型耗散孤子光谱; (b) 示波器脉冲序列; (c) 基频处的信噪比, 插图为3 GHz带宽的射频谱; (d) 庞加莱球上偏振态演化轨迹; (e)正交偏振分量的功率; (f) DOP和相位差
图 3 160 mW抽运功率下偏振吸引子的动态调控 (a) 单向调节PC对应偏振吸引子的变化; (b)对应光谱变化; (c)对应DOP的变化