提出并证明了一种宽光谱被动锁模掺铒光纤激光器,为光学频率梳和光纤飞秒脉冲的 产生奠定了基础。基于非线性偏振旋转的锁模机理,该激光器在大的正常色散区合理地 将C波段和L波段掺铒光纤结合,确保激光器具有C+L波段的增益谱覆盖。泵浦功率为350 mW时脉冲以基频4.32 MHz稳定地运转, 3 dB 带宽为60 nm, 20 dB覆盖了1522～1630 nm, 实现了增益带宽内光谱的完全覆盖。这种利用增益拼接加宽光谱的方法可以有效避免 光谱成分的非线性相位噪声,有利于进一步压窄脉冲。

A broadband erbium-doped passively mode-locked fiber laser is proposed and demonstrated. It lays the foundation for optical frequency comb and generation of fiber femtosecond pulse. Based on the mode-locked mechanism of nonlinear polarization rotation, the laser combines C-band and L-band erbium-doped fiber reasonably in large normal dispersion region to ensure that the laser has a gain spectrum coverage of C+L band. When the pump power reaches 350 mW, the pulses operate stably with fundamental frequency of 4.32 MHz, 3 dB bandwidth is 60 nm and 20 dB spectrum covers from 1522 nm to 1630 nm. The full coverage of gain bandwidth is achieved. The method can effectively avoid nonlinear phase noise of spectrum components by using gain splicing to broaden spectrum, and it is conducive to further compress pulse.