1 Department of Physics, College of physics and Electronic Engineering, Northeast Petroleum University, Daqing 163318, Heilongjiang , China
2 Department of Physics, College of Electrical Engineering, Suihua University, Suihua 152000, Heilongjiang , China
We present a theoretical study of the one-dimensional modulational instability of a broad optical beam propagating in a biased photorefractive crystal with both linear and quadratic electro-optic effects (Kerr effect) under steady-state conditions. One-dimensional modulational instability growth rates are obtained by treating the space-charge field equation globally and locally. Both theoretical reasoning and numerical simulation show that both the global and local modulational instability gains are governed simultaneously by the strength and the polarity of external bias field and by the ratio of the intensity of the broad beam to that of the dark irradiance. Under a strong bias field, the results obtained using these two methods are in good agreement in the low spatial frequency regime. Moreover, the instability growth rate increases with the bias field, and the maximum instability growth occurs when ratio of light intensity to dark irradiance is 0.88.
nonlinear optics photorefractive effects spatial soliton modulational instability 激光与光电子学进展
2024, 61(5): 0519001
Author Affiliations
Abstract
1 School of Physics and Optoelectronics, State Key Laboratory of Luminescent Materials and Devices, Guangdong Engineering Technology Research and Development Center of Special Optical Fiber Materials and Devices, Guangdong Provincial Key Laboratory of Fiber Laser Materials and Applied Techniques, South China University of Technology, Guangzhou, China
2 Research Institute of Future Technology, South China Normal University, Guangzhou, China
In this work, we present a high-power, high-repetition-rate, all-fiber femtosecond laser system operating at 1.5 $\unicode{x3bc}$ m. This all-fiber laser system can deliver femtosecond pulses at a fundamental repetition rate of 10.6 GHz with an average output power of 106.4 W – the highest average power reported so far from an all-fiber femtosecond laser at 1.5 $\unicode{x3bc}$ m, to the best of our knowledge. By utilizing the soliton-effect-based pulse compression effect with optimized pre-chirping dispersion, the amplified pulses are compressed to 239 fs in an all-fiber configuration. Empowered by such a high-power ultrafast fiber laser system, we further explore the nonlinear interaction among transverse modes LP01, LP11 and LP21 that are expected to potentially exist in fiber laser systems using large-mode-area fibers. The intermodal modulational instability is theoretically investigated and subsequently identified in our experiments. Such a high-power all-fiber ultrafast laser without bulky free-space optics is anticipated to be a promising laser source for applications that specifically require compact and robust operation.
high-power femtosecond fiber laser high repetition rate intermodal modulational instability nonlinear pulse compression High Power Laser Science and Engineering
2023, 11(4): 04000e50
1 湖南城市学院 信息与电子工程学院, 湖南 益阳 413000
2 吉首大学 物理与机电工程学院, 湖南 吉首 416000
3 铜仁学院 大数据学院, 贵州 铜仁 554300
借助线性稳定性分析方法,推导出包含非线性耦合作用的锯齿型光波导阵列中平面波的离散调制稳定性增长率的解析表达式,并针对不同次近邻耦合系数分析了非线性耦合作用对调制不稳定性区域的影响.结果表明,改变非线性耦合系数的值会明显影响调制不稳定区域的形状.根据调制稳定性分析结果,预测了亮离散孤子可能存在的参数区域.然后,利用一种准离散的多重尺度方法得到了此锯齿型光波导阵列中亮离散孤子的解析解,并分析了它们的存在条件,结果与离散调制不稳定性分析预测的存在条件基本一致.
非线性光学 光波导 锯齿晶格 非线性耦合 调制不稳定性 亮孤子 Nonlinear optics Optical waveguide Zigzag lattice Nonlinear coupling Modulational instability Bright soliton
1 桂林航天工业高等专科学校 电子信息工程系, 广西 桂林 541004
2 桂林电子科技大学 信息与通信学院, 广西 桂林 541004
本文利用时间相关的变分法对准二维的非线性薛定谔方程平面波的调制不稳定性进行了研究。在拉格朗日变分的框架下推导出相与振幅的演化方程,进而对线性化扰动方程的解进行了数值模拟,直观地展示了平面波的调制不稳定性。最后通过对能量方程有效势的分析,严格地得到了平面波解调制不稳定的判断准则。
非线性光学 调制不稳定性 色散关系 变分法 非线性薛定谔方程 nonlinear optics modulational instability dispersion relations variational method nonlinear Schrdinger equation
西南交通大学 信息科学与技术学院，四川 成都610031
文章从色散管理孤子(DMS)在光纤中传输满足的非线性薛定谔方程出发，推导出DMS系统中调制不稳定性(MI)增益谱的表达式，并给出了数值模拟结果。结果表明：色散管理图强度越强，对MI过程产生的增益的抑制作用越大；路径平均色散越大，抑制MI过程产生的增益越明显。
色散管理 调制不稳定性 光纤通信 dispersion management modulational instability fiber-optic communication
1 东南大学电子工程系光子学与光通信研究室，南京 210096
2 南京林业大学信息科学技术学院，南京 210037
3 南京晓庄学院物理系，南京 210017
以三、四阶色散项的耦合非线性薛定谔方程为基础，考虑光纤损耗及高阶色散，研究了双光束在零色散附近的交叉相位调制不稳定性．理论上导出描述交叉相位调制不稳定性的色散方程，并进行数值模拟计算．结果表明：由于四阶色散的影响，在光纤的正常、反常色散区，交叉相位调制不稳定性均发生在两个频谱区．如光脉冲工作在最小群速度色散附近时，四阶色散对光纤的交叉相位调制不稳定性将起决定性作用，可使增益谱出现一个新的峰值．光纤损耗使增益的谱宽变窄．对给定的传输距离，随着光纤向零色散附近靠近，两个频谱区谱宽增加直到相互重叠．数值分析了两光波有差别时的交叉相位调制不稳定性．
交叉相位调制不稳定性 四阶色散 光纤损耗 Cross-phase modulational instability Fourth-order dispersion Fiber loss
以包含了三、四阶色散项的耦合非线性薛定谔方程为基础，重点研究了三、四阶色散对交叉相位调制不稳定性的影响。结果表明
光纤光学 交叉相位调制不稳定性 四阶色散 增益谱
中国海洋大学 光学·光电子实验室, 山东 青岛 266071
从带五次非线性项的扩展非线性薛定谔方程出发,重点考虑了五次非线性对常用的自聚焦光纤中反常色散区调制不稳定性的影响。研究结果表明,当入射功率较小时,五次非线性对调制不稳定性的影响并不明显,这说明了当入射功率很小时,忽略非线性薛定谔方程中五次非线性项的做法是合理的;随着入射功率的增加,五次非线性对调制不稳定性的影响越来越大,这种影响主要表现为五次非线性增大了调制不稳定性频谱的范围及增益值,并最终减小了使调制不稳定性发生的入射功率范围;当入射功率继续增加,超过一定的阈值条件时,调制不稳定性不能发生。
非线性光学 调制不稳定性 五次非线性
1 Institute of Quantum Electronics, South China Normal University, Guangzhou 510631
2 Physics Department, Hengyang Teachers College, Hunan 421008
Chinese Journal of Lasers B
1997, 6(6): 533
