全正常色散锁模PbSe量子点光纤激光器的数值研究

Numerical Investigation of All-Normal Dispersion Mode-Locked PbSe Quantum Dot Fiber Laser

为突破传统光纤激光器因增益介质为稀土掺杂光纤,辐射波长相对固定的困境,由于量子点尺寸依赖的辐射波长,本文提出全正常色散锁模PbSe量子点光纤激光器,通过数值计算得到了1.7μm稳定的耗散孤子锁模,并系统地数值研究了使用该激光器输出耗散孤子的启动动力学、谐振腔内激光的演化和激光器的稳态输出特性,探索了增益光纤的长度和浓度、谐振腔的长度对输出特性的影响。当泵浦功率为0.1 W时,最佳的增益光纤长度为0.3 m,掺杂浓度为12×10^(21) m^(−3),此时的脉冲宽度为7.59 ps,光谱的宽度为13.77 nm,耗散孤子在单模光纤长度为2~7 m范围内保持稳定。当被动光纤长度为0.1 m时,激光器输出了22个峰、包络宽度为22.33 nm的多波长激光,光谱覆盖了1678~1724 nm,此时时域中观察到一对间隔为4 ps、单脉冲宽度为0.92 ps的孤子对。该研究结果对超快量子点光纤激光器的建立和优化提供了理论指导,为特殊波长超快光纤激光提供了新的选择。

To address the problem of limited wavelength output by a traditional fiber laser for its gain medium of rareearth-ion-doped fiber owing to the size-dependent wavelength of quantum dots,an all-normal dispersion mode-locked fiber laser with PbSe quantum dot as the gain medium is demonstrated and studied through numerical simulation.A stable dissipative soliton of 1.7μm is obtained by calculation.The buildup dynamics,evolution in the cavity,and output characteristics in a steady state of generating dissipative solitons using a PbSe quantum dot fiber laser are investigated systematically.Influences with respect to the length and doping concentration of the gain fiber and the length of the passive fiber are explored.The optimal gain fiber length and doping concentration obtained under a pump power of 0.1 W are 0.3 m and 12×10^(21)m^(−3)respectively,corresponding to a pulse duration of 7.59 ps and a spectral width of 13.77 nm.However,the steady-state disappears beyond a passive fiber length range of 2-7 m.Furthermore,when the passive fiber is 0.1 m,a multiwavelength output is generated by the laser,with 22 peaks,a spectral range of 1678-1724 nm,and an envelope width of 22.33 nm.In the time domain,a dual soliton is emitted with a width of 0.92 ps and a pulse interval of 4 ps.This work provides theoretical guidance for establishing and optimizing an ultrafast quantum dot fiber laser and a new option for fiber lasers of special wavelengths.