掺Yb^(3+)光纤F-P腔被动锁模激光器的实验研究

Experimental study on passive mode-locked Yb^(3+) doped fiber laser with F-P cavity

掺镱(Yb3+)光纤被动锁模激光器谐振腔采用线性腔结构,腔内插入二分之一波片和偏振分束器引入偏振旋转,结合半导体可饱和吸收镜的自起动,实现稳定的被动锁模运转。腔内插入光栅对,提供负的群速度色散,以补偿光纤所带来的正色散,达到压缩脉宽的目的。当泵浦功率为300 mW、光栅对的距离为10cm时,获得稳定的锁模运转,锁模输出功率28 mW,脉冲重复频率20 MHz,输出光谱宽度达15 nm,按脉冲变换极限公式,其脉冲时间宽度与频带宽度的乘积为0.315计算,脉宽可达100 fs以下。

The oscillator utilized a linear（F-P） cavity in which the halfwave plates and polarization splitters were placed to introduce polarization rotation. Combining the self-starting of semiconductor saturable absorber mirror, the passive mode-locked operation was achieved. The grating pair, providing negative group velocity dispersion, compensated the positive dispersion of fiber to compress the pulse. The stable mode-locked was operated with a pump power of 300 mW and the distance between the grating pair was 10cm. The mode-locked output power was 28 mW while the pulse repetition was 20 MHz and the output spectrum width was 15 nm. The pulse width was less than 100 fs calculated by the formula that time bandwidth product equal to 0. 315.