被动锁模掺铒光纤激光器中的有理数谐波锁模

摘要

To achieve a steady harmonic modelocked pulse (HMLP), the theory of rational harmonic modelocking and the transmission characteristics of a nonlinear amplifying loop mirror were analyzed. A figure8 shape pulse laser including an outer ring and an inner ring was constructed to theoretically and experimentally investigate the passively modelocked technology of an erbiumdoped fiber laser. By modulating the pump power to 167 mW,146 mW or 126 mW,not only a steady HMLP,but also several rational HMLPs were observed. It is found that these pulses show the same properties as those of 3thorder,5thorder,6thorder HMLPs by analyzing the repetition rate of pulse train. The reason is that the Sagnac ring in the figure8 shape pulse laser plays the same role as the modulator used in an actively modelocked pulse laser.%为了获得稳定的谐波锁模脉冲,分析了有理数谐波锁模的理论和非线性放大环镜的传输特性.构建了包括一个外部环和一个内部环的8字形被动锁模掺铒脉冲光纤激光器,对被动锁模掺铒光纤激光器进行了相关理论分析和实验研究.实验发现,当调整泵浦功率分别为167,146和126 mW时,除了观测到了稳定的谐波锁模脉冲外,还观察到了分别类似于3阶、5阶、6阶的有理数谐波锁模脉冲产生现象,分析其脉冲重复频率,证实此类脉冲序列具有属于3阶、5阶和6阶有理数谐波锁模脉冲序列重复频率的一样的规律,认为其产生原因是8字形光纤激光器中的Sagnac环起了和主动锁模中调制器一样的作用.