理论结合实验分析了多芯光子晶体光纤激光器被动锁模的脉冲形成过程,主要包括弛豫振荡、Q脉冲、稳定锁模3个阶段.由于纤芯之间较强的渐消场耦合作用,不同纤芯内脉冲的演变过程一致,并最终实现同步稳定锁模运转.研究结果表明:多芯光子晶体光纤锁模无需精细的光纤耦合调节,在保证耦合效率的前提下都可以实现纤芯之间的同步锁模.
The pulse formation process in a passively mode-locked multi-core photonic crystal fiber laser with saturable absorber was investigated experimentally and numerically. The starting procedure included relaxation oscillation, Q pulses and finally stable mode-locking. The oscillation tendency between the cores was almost the same because of the strong evanescent coupling between the cores. The research shows that ensuring the coupling efficiency, the fine adjustment of fiber input coupling is not required for stable mode locking.