搭建了基于光纤迈克耳孙干涉仪的跳模检测系统，对抽运调制条件下的超窄线宽掺铒光纤环形激光器的跳模特性进行了实验研究，测量了由抽运电流标定的表征跳模规律的跳模数据图。结果表明，随着抽运电流的不断增加，激光器先后经历模式稳定区、模式非稳区以及多纵模区三种状态；存在第二抽运阈值，当抽运强度超过这一阈值时激光器由单纵模跳变为非稳定的多纵模。掺铒光纤环形激光器的谐振腔因抽运热效应或外界扰动而变化时，会引发频率漂移与连续跳模现象。

One type of mode-hopping detection system based on fiber Michelson interferometer is set up. The influence of pump modulation on the mode-hopping characteristics of ultra-narrow linewidth erbium-doped fiber ring laser is investigated experimentally through the system. The mode-hopping map of laser labeled by pump current is measured to reveal the mode-hopping characteristics. Numerical results show that the laser will orderly experience steady single-mode area, unsteady single-mode area and multimode area with the pump current increasing, and there exists a second threshold over which the laser will hop from single-mode into drastic multimode. Besides, frequency drift going with serial mode hops can be excited by pump-induced thermal effect or hostile disturbances applied on the laser cavity.