Asynchronous Energy and Polarization Dynamics of Symmetry‐Broken GHz Dissipative Solitons
Yuncong Ma, Pengxiang He, Wei Lin, Xiaoxiao Wen, Xu Hu, Haijiao Xu, Xuewen Chen, Zhijin Xiong, Yang Yang, Xiaoming Wei, Zhongmin YangABSTRACT
The existence of polarization symmetry breaking (PSB) in dissipative vector solitons has been discovered in the steady‐state GHz‐repetition‐rate fiber laser. However, the transient physical processes that govern the PSB's initial formation and dynamic buildup remain largely unknown, leaving the complete physical picture unclear. In this study, we investigate the transient dynamics of the PSB state in a GHz fiber laser by developing a polarization‐resolved time‐lens oscilloscope. This technique achieves sub‐picosecond temporal resolution at a refresh rate of 20 MHz, such that the asynchronous buildup between the total energy and energy ratio of the orthogonal polarizations are unveiled, demonstrating that a full polarization evolution lags behind the energy evolution. Such evolving trait of the PSB state is also corroborated by numerical calculations based on a bidirectional linear‐cavity model. Meanwhile, a continuous variation of the polarization evolution frequency of the PSB state is identified. This change in oscillatory behavior has shown to correlate with variations in the repetition rate of the fiber laser. These results highlight the validity of the time‐lens‐based approach in analyzing the GHz dissipative solitons, and the findings can provide valuable insights into the essence of PSB, as well as the dynamic‐gain‐driven GHz dissipative soliton in the ultrafast community.