掺Er^(3+)氟化物光纤振荡器中红外超短脉冲的产生  

Theoretical study on generating mid-infrared ultrashort pulse in mode-locked Er^(3+):ZBLAN fiber laser

作　　者：王少奇[1,2,3,4] 邓颖[1,4] 张永亮[1] 李超[1] 王方[1] 康民强[1] 罗韵[1] 薛海涛[1] 胡东霞[1,4] 粟敬钦[1,3,4] 郑奎兴[1] 朱启华[1,3,4] 

机构地区：[1]中国工程物理研究院激光聚变研究中心,绵阳621900 [2]中国工程物理研究院研究生院,北京100088 [3]等离子体物理重点实验室,绵阳621900 [4]上海交通大学IFSA协同创新中心,上海200240

出　　处：《物理学报》2016年第4期109-116,共8页Acta Physica Sinica

摘　　要：基于非线性薛定谔方程建立了氟化物(ZrF_4-BaF_2-LaF_3-AlF_3-NaF,ZBLAN)光纤振荡器中产生中红外超短脉冲的理论模型,在此基础上研究了中红外超短脉冲在氟化物光纤振荡器中形成的物理机理,数值模拟了氟化物光纤振荡器中中红外超短脉冲的演化过程.分析了腔内净色散和小信号增益系数对振荡器中锁模脉冲产生的影响,并给出了参数设置范围.研究发现:当掺Er^(3+)氟化物光纤长度,小信号增益系数,不饱和损耗为一定值时,腔内净色散在一定范围内才会出现稳定的锁模脉冲,且随着腔内净色散增加脉冲宽度变宽,光谱变窄,峰值功率降低;当掺Er^(3+)氟化物光纤长度及不饱和损耗一定,腔内净色散量为合理值,小信号增益系数在合理的范围时可以得到稳定的锁模脉冲,且随着小信号增益系数的增加脉冲宽度变宽,光谱变宽,峰值功率增加.Fiber lasers show several advantages over other types of lasers. They are efficient, compact, and rugged since they require few bulk components and are virtually unaffected by the surrounding environment. Mode-locked mid-infrared （mid-IR） lasers are essential for a wide variety of applications. The promising applications of mode-locked fiber lasers at wavelengths near 3 μm include combs generation （metrology）, spectroscopic sensors, infrared countermeasures, laser surgery, high-efficient pump sources for longer-wavelength oscillators and mid-IR supercontinuum source pmnping. Based on the nonlinear SchrSdinger equation （NLSE）, a theoretical model of passively mode-locked Er3＋-doped fluoride fiber laser using a saturable absorber is set up. Some mechanisms for generating mid-IR ultrashort pulse in fiber lasers are investigated. When the dispersion of the cavity is managed properly, the numerical simulation mainly focuses on the evolution process of mid-IR ultrashort pulse in fluoride fiber oscillators. Influences of the intracavity net dispersion and the small-signal gain on the generation of mode-locked pulses are analyzed in detail. And the reasonable parameter windows are given. Just as the simulated results showed, for a case of 4 m Er3＋-doped fluoride fiber, small-signal gain go = 0.6 m 1 and unsaturated loss lo = 0.7, the stable mode-locked pulses are achieved by tuning the net intracavity dispersion within a certain range from 0.72 ps2 to 0.83 ps2. As the net intracavity dispersion increases, the output pulse duration increases gradually, while the spectrum width （FWHM） and peak power decrease accordingly. In addition, for the case of 4 m Er3＋-doped fluoride fiber, unsaturated loss l0 = 0.7 and net intracavity dispersion of 0.8 ps2, the stable mode-locked pulses can also be obtained by tuning the small-signal gain within a certain range from 0.55 to 0.70 m-1. As the small-signal gain increases, the output pulse duration, spectral width, and peak power increase gradually. This work may

关 键 词：光纤激光器 中红外 超短脉冲 氟化物光纤 

分 类 号：TN752[电子电信—电路与系统]