超低阈值Q调制,锁模Yb^(3+)光纤环形腔激光器

Mode-locked and Q-modulation switched Yb^(3+) doped ring cavity fiber laser with low pump power

在一种掺镱(Yb3+)光纤锁模激光器中。谐振腔采用近"8"字形环形结构,并巧妙地引入半导体可饱和吸收镜(SESAM),腔内引入起偏器和偏振控制器,利用非线性偏振旋转的被动锁模机理,结合SESAM慢可饱和吸收体的自启动作用,在极低的泵浦功率下,实现了稳定的调Q脉冲输出和锁模输出。当泵浦功率为18 mW时,调Q脉冲重复频率为16 kHz,脉冲宽度4μs,光谱宽度为2.34 nm。当泵浦功率为60 mW时,实现了激光器连续锁模,输出功率8 mW,重复频率20 MHz,光谱宽度3.54 nm,脉宽在ps和亚ps量级,而且在调整偏振控制器的角度时,观察到了波长的调谐现象,调谐范围为1 028~1 530 nm。

The experimental study of a passive mode-locked Yb^3＋ -doped fiber laser was reported, which utilized a 8-shaped ring cavity with semiconductor saturable absorber mirror（SESAM） as well as the polarizer and polarization controllers. Combining the effect of nonqinear polarization rotation with the self-starting of SESAM, stable operations of Q-switched and CW modelocked regime at the low pump power were achieved. When the pump power was 18 mW, the Q-switched pulse with a repetition of 16 kHz, a pulse width of 4 μs ,and an output spectrum width of 2.34 nm was obtained. When the pump power was 60 mW, the output power of mode-locked pulses was 8 mW, the repetition was 20 MHz, the output spectrum width was 3.54 nm, and the pulse width was ps or sub ps orders. The tunable phenomenon with proper adjustment of the polarization controllers＇ orientations was observed, and the tunable range was 1 028～1 053 nm.