Lv Changjian, Meng Fanchao, Yan Qi, Zhang Tianqi, Tian Yiwei, Jia Zhixu, Dong Wei, Qin Weiping, Qin Guanshi
Opt Express. 2024 Jan 15;32(2):1851-1863. doi: 10.1364/OE.514835.
We demonstrate a bidirectional mode-locked erbium-doped fiber laser by incorporating gold nanofilm as a saturable absorber (SA). The gold nanofilm SA has the advantages of high stability and high optical damage threshold. Besides, the SA exhibits a large modulation depth of 26% and a low saturation intensity of 1.22 MW/cm at 1.56 μm wavelength band, facilitating the mode-locking of bidirectional propagating solitons within a single laser cavity. Bidirectional mode-locked solitons are achieved, with the clockwise pulse centered at 1568.35 nm and the counter-clockwise one at 1568.6 nm, resulting in a slight repetition rate difference of 19 Hz. Moreover, numerical simulations are performed to reveal the counter-propagating dynamics of the two solitons, showing good agreement with the experimental results. The asymmetric cavity configuration gives rise to distinct buildup and evolution dynamics of the two counter-propagating pulses. These findings highlight the advantage of the gold nanofilm SA in constructing bidirectional mode-locked fiber lasers and provide insights for understanding the bidirectional pulse propagation dynamics.
我们通过将金纳米薄膜用作可饱和吸收体（SA）来演示一种双向锁模掺铒光纤激光器。金纳米薄膜SA具有高稳定性和高光学损伤阈值的优点。此外，该SA在1.56μm波长波段表现出26%的大调制深度和1.22MW/cm的低饱和强度，有利于在单个激光腔内双向传播孤子的锁模。实现了双向锁模孤子，顺时针脉冲中心波长为1568.35nm，逆时针脉冲中心波长为1568.6nm，导致轻微的重复频率差为19Hz。此外，进行了数值模拟以揭示两个孤子的反向传播动力学，与实验结果显示出良好的一致性。非对称腔结构导致两个反向传播脉冲具有不同的建立和演化动力学。这些发现突出了金纳米薄膜SA在构建双向锁模光纤激光器方面的优势，并为理解双向脉冲传播动力学提供了见解。
