超短脉冲掺Yb^(3+)光纤激光器实验研究

Experimental Study of Ultrashort Pulse Yb 3+-Doped Fiber Laser

报道了使用976 nm半导体激光器作为抽运源,以掺Yb3+光纤作增益介质构成环形腔激光器产生超短脉冲的实验研究。在腔体净群速度色散为正的掺Yb3+光纤环形腔激光器中,采用非线性偏振旋转的相加脉冲锁模技术,通过调节偏振控制器的方向和减少腔内损耗,实现稳定的锁模运转。用示波器观察光纤激光器在时域的输出特性,在抽运光一定的情况下,随着光偏振状态的变化,光纤激光器锁模激光的变化呈现稳定和不稳定两个区域。在不稳定锁模区域,激光为不规则的脉冲。通过仔细调节光纤偏振控制器的位置,当光纤偏振控制器在某一适当位置时,激光器工作在稳定的锁模区域,获得最大功率为 9 .46 mW,脉冲激光光谱宽度为 10 nm,脉冲的重复频率为15 .4 MHz。

The experimental study of the Yb3+-doped fiber ring laser of ultrashort pulse is reported, which is pumped by 976 nm semiconductor laser. In the normal dispersion, using the additive pulse mode-locking based on nonlinear polarization evolution, the Yb3+-doped fiber laser can oscillate in the mode-locked state by adjusting the position of the polarization controller (PC) and reducing the loss in the cavity. The output characteristics of the fiber laser are shown by oscillograph in the time domain. If pump power is not changed, along with the change of the polarization of the pulse, the changes of output pulse maintain stable and unstable states. In the unstable region, the pulse becomes irregular. When PC is in a proper position, the laser operates a stable and mode-locked state by adjusting the PC1 and PC2 carefully. The maximum output power of the laser is 9.46 mW, at the repetition rate of 15.4 MHz corresponding to ∼10 nm spectrum width.