室温下稳定的多波长掺铒光纤激光器的研究

通过在线形谐振腔中引入一段缠绕在压电陶瓷上的单模光纤作为正弦相位调制器，使得激射波长的损耗不固定，抑制由于掺铒光纤的均匀展宽效应引起的模式竞争，从而避免了在室温下不稳定的单波长激射，实现了多波长掺铒光纤激光器的稳定输出。为了获得平坦的多波长输出，在谐振腔里使用了一个损耗峰位于1530nm处的长周期光纤光栅，以获得较为平坦的增益谱。通过两个3dB耦合器制成的反射型梳状滤波器的滤波作用，实验中观察到稳定的多波长激射，相邻波长间隔约为0．45nm。中心9个波长的输出功率平坦度为10dB，边模抑制比大于25dB。

A sinusoidal phase modulator composed of a piece of single-mode fiber around a piezoelectric transducer is inserted in the linear resonant cavity, which makes the loss corresponding to different lasing lines uncertain, the mode competition owing to the homogeneous broaden line in erbium-doped fiber is suppressed and the unstable single-wavelength lasing at room temperature is eliminated. In order to achieve flat multi-wavelength output, a long-period fiber grating with loss peak at 1530 nm is used to obtain flat gain spectrum. The stable output from the multi-wavelength erbium-doped fiber laser is realized. Simultaneous multi-wavelength lasing is observed with 0.45 nm intervals defined by the reflective comb-like filter. In the meantime, there are 9 lasing lines in power differences less than 10 dB and the side-mode suppression ratio is higher than 25 dB.