被动锁模光纤激光器中泵浦滞后现象的研究

Pump Hysteresis Phenomena in Passively Mode-locked Fiber Laser

研究了基于非线性偏振旋转技术的被动锁模光纤激光器中的泵浦滞后现象.用非线性传输模型对泵浦功率滞后的机理进行了分析,发现此激光器中的泵浦滞后现象起因于光纤双折射与偏振选择共同作用引起的激光腔内非线性损耗特性.对泵浦滞后现象进行数值模拟和实验验证,结果与非线性传输模型分析的结论一致,并进一步证实了泵浦滞后现象不仅在连续光锁模产生孤子时存在,在锁模态下孤子的产生和泯灭过程中仍然存在.此外,随着激光腔内孤子数目的增多泵浦滞后现象愈加明显.

Pump power hysteresis effect is investigated in a fiber laser based on nonlinear polarization rotating technique. The physical mechanism is analyzed with the nonlinear transmission model, and it is found that the pump hysteresis arises from the combined effects of fiber birefrengece and polarization selection,which lead to a nonlinear loss property of the laser cavity. Experimental and simulation results agree well with the the theoretical prediction, and demonstrate that the pump power hysteresis occurs when mode-locked solitons generated from a continuous wave state,and takes place in the process of the solitons created and annihilated after the laser coming into mode-locked state. Moreover, the hysteresis becomes more obvious as the number of the solitons increases.