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非线性薛定谔方程是光脉冲在光纤中传播时所遵循的基本方程.本文利用分步傅里叶方法从数值结算的角度研究了具有线性啁啾的光脉冲在具有横向增益光纤中的自相似传播特性.研究表明:当群速度色散系数和光脉冲的啁啾系数符号相同时,由于在传播过程中自相位调制和群速度色散分别起主要作用,不论何种形式的光脉冲在传输过程中均会受到压缩,但随着传播距离的增加压缩的光脉冲会展宽;埃尔米特高斯输入和正弦输入在传播过程中的光强分布是对称的,拉盖尔高斯输入在传播过程中会发生能量交换而表现出明显的偏转;当群速度色散系数和光脉冲的啁啾系数符号不相同时,在传播过程中群速度色散始终起主要作用,脉冲一直展宽.这些研究结论可能为未来光纤压缩器、光纤放大器以及新型THz调制波源的制备提供新的理论基础和方法. 相似文献
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提出了磁光光纤Bragg光栅的理论模型,给出了圆偏振光在磁光光纤光栅中传播的非线性耦合模方程. 研究表明,在磁光光纤Bragg光栅中,光栅引起正反传播方向的导波光发生耦合,法拉第效应引起磁圆双折射效应,而非线性效应则将左旋和右旋圆偏振光耦合在一起,它们的共同作用可使双稳态状态发生反转、非线性光控光开关阈值功率降低. 与传统光纤光栅相比,利用左旋和右旋磁圆偏振光之间的交叉相位调制实现的脉冲整形具有磁光偏置可调特性,为基于磁光光纤光栅的动态灵活全光3R再生器的研制提供了理论基础.
关键词:
磁光光纤Bragg光栅
圆偏振光
脉冲整形 相似文献
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非线性薛定谔方程是光脉冲在光纤中传播时所遵循的基本方程.本文利用分步傅里叶方法从数值结算的角度研究了具有线性啁啾的光脉冲在具有横向增益光纤中的自相似传播特性.研究表明:当群速度色散系数和光脉冲的啁啾系数符号相同时,由于在传播过程中自相位调制和群速度色散分别起主要作用,不论何种形式的光脉冲在传输过程中均会受到压缩,但随着传播距离的增加压缩的光脉冲会展宽;埃尔米特高斯输入和正弦输入在传播过程中的光强分布是对称的,拉盖尔高斯输入在传播过程中会发生能量交换而表现出明显的偏转;当群速度色散系数和光脉冲的啁啾系数符号不相同时,在传播过程中群速度色散始终起主要作用,脉冲一直展宽.这些研究结论可能为未来光纤压缩器、光纤放大器以及新型THz调制波源的制备提供新的理论基础和方法. 相似文献
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反射型体全息光栅对超短脉冲激光光束衍射的性质 总被引:2,自引:2,他引:0
在光栅记录介质色散效应的影响下,拓展Kogelnik的耦合波理论研究了反射型体全息光栅对偏振方向垂直和平行于入射面的超短脉冲激光光束衍射的性质。结果表明对于记录在LiNbO3光折变晶体中的体全息光栅,在色散效应、光栅参量和入射条件的共同影响下,光栅对偏振方向垂直于入射面的超短脉冲激光光束衍射的光谱带宽大于对偏振方向平行于入射面的超短脉冲激光光束衍射的光谱带宽,在不考虑光栅介质色散效应的影响时,它们都变大。进一步给出了衍射光的光谱带宽及光栅的衍射效率随入射脉冲的光谱带宽与光栅的光谱带宽比值的变化情况。 相似文献
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通过在能量较高、考虑非线性时,求解光纤光栅非线性耦合模方程连续波条件下的解,得到光纤光栅失谐量δ与光脉冲传播常量q的非线性色散关系和光栅致群速度色散系数βg2与δ的关系.用MATLAB绘图,得到非线性参量γ和光脉冲能量P0的乘积γP0对色散和βg2的影响.结果表明:随着βg2的增加,非线性色散曲线的上、下两支向δ的负值区移动,当超过某一临界值时,曲线上支开始形成环,这时光纤光栅引起的群速度色散中的反常色散区消失,全部变成正常色散. 相似文献
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负啁啾脉冲在正负色散光纤中传输特性研究 总被引:5,自引:2,他引:3
对负啁啾脉冲在正常色散光纤中传输特性进行了数值分析和实验研究,数值分析与实验结果基本一致。数值分析和实验证明正常色散光纤不仅能压窄负啁啾的脉宽而且能压窄频谱,采用正常色散光纤消啁啾后用色散位移光纤为传输媒质成功地进行了一阶和高阶孤子传输。 相似文献
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色散缓变光纤的非线性啁啾效应 总被引:7,自引:0,他引:7
由于光孤子在光纤中传输受到啁啾效应等多种因素的影响 ,使孤子脉宽展宽 ,光脉冲在终端变得不可检测 ,严重影响误码率 ,所以研究不同因素对孤子脉宽的影响有其重要意义。本文求解了色散缓变光纤中含频率非线性啁啾效应的NLS方程 ,由得到的孤子解讨论了非线性啁啾效应和色散缓变效应对孤子脉宽的影响 ,由此说明 ,色散缓减效应等效长距离分布参数光纤放大器的增益 ,它导致非线性效应增加 ,孤子进一步被压缩 ,非线性啁啾效应使孤子在z值较小时 ,其脉宽收缩 ,在z值较大时又使孤子脉宽展宽。 相似文献
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Passive optical waveform generation is obtained in fiber lasers using a 1.3-μm semiconductor optical amplifier (SOA) as the
gain medium. Various waveforms, including square wave, staircase wave, triangular wave, pulse, and dark pulse are generated
in SOA-based fiber lasers by adjusting intracavity polarization controllers. The passive waveform generation might be attributed
to the SOA gain dynamics and the enhanced nonlinear interaction at the 1.3-μm zero dispersion wavelength of traditional single-mode
fiber (SMF), as well as the interference effect between the two sub-cavities of fiber laser. With figure-8 cavity configuration,
1250th-order harmonic pulses have been successfully demonstrated. We have also obtained a free-running SOA-based fiber laser
with 3-dB spectral width of 16 nm, and the center wavelength can be tuned over 45 nm range. 相似文献
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Influences of cavity dispersion distribution on the output pulse properties of an all-normal-dispersion fiber laser
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《中国物理 B》2015,(7)
In this paper, the influences of the dispersion distribution in the cavity on the output pulse properties of the all-normaldispersion(ANDi) fiber laser are investigated. Our simulations show that, as the relative length of the dispersion fiber increases, the temporal width and the spectral bandwidth of the output pulse for an ANDi fiber laser with fixed total cavity dispersion or fiber length are decreased, while the pulse energy is enhanced and the compressed pulse width is increased.These simulation predictions have been proved by our experimental results. The reason may be that the nonlinear phase shift accumulated in the nonlinear fiber is more than that in the dispersion fiber if they have the same length. 相似文献
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A cascade fiber-optic system that generates pulses of high spectral density by using the effect of nonlinear spectral compression is proposed. It is demonstrated that the shape of the pulse envelope substantially influences the degree of compression of its spectrum. In so doing, maximum compression is achieved for parabolic pulses. The cascade system includes an optical fiber exhibiting normal dispersion that decreases along the fiber length, thereby ensuring that the pulse envelope evolves toward a parabolic shape, along with diffraction gratings and a fiber spectral compressor. Based on computer simulation, we determined parameters of cascade elements leading to maximum spectral density of radiation originating from a subpicosecond laser pulse of medium energy. 相似文献
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The phenomenon of temporal pulse dispersion, which is a key characteristic of an optical fiber communication system is described
from the first principles. Beginning with the basics of dispersion in a bulk medium, these concepts are then applied to propagation
of a pulse in an optical fiber. Details of modeling dispersion are then described in the context of dispersion tailoring and
dispersion compensation with a view to form the foundation for subsequent chapters on dispersion compensation that follow
in this report. Basic physics behind the design target for dispersion compensating fibers is discussed, which should be useful
to fiber designers. 相似文献
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用变分法研究高阶色散和五阶非线性对高斯脉冲在光纤中传输特性的影响 总被引:10,自引:1,他引:9
从修正的非线性薛定谔方程出发,采用变分法,导出了在高阶色散和五阶非线性共同作用情况下高斯型脉冲参量随传输距离的演化方程组;求出了振幅与脉宽、频率与啁啾、脉宽与啁啾之间的三个重要约束关系;并进一步得出了脉宽随传输距离演化的解析解和脉冲中心位置随传输距离的演化规律;描绘了高阶色散和五阶非线性下,脉宽随传输距离演化的图形.结果表明:光纤中的高阶色散和五阶非线性都会影响高斯型脉冲各个参量的演化,但脉宽和振幅间的绝热关系并未改变.高阶色散使高斯型脉冲的脉宽展宽,五阶非线性使高斯型脉冲的脉宽压缩,它们对脉宽或初始啁啾的影响可以在一定程度上抵消,从而有可能使脉冲近似实现保形传输. 相似文献
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Xiaohong Zhou Xiaorong Gao Li Wang Zeyong Wang Bin Luo Jinlong Li 《Optics & Laser Technology》2012,44(7):2120-2124
In chirped pulse amplification, the amplification of an optical pulse in laser amplifying medium is a very important link. After considering dispersion, Kerr nonlinear effect, gain distribution and loss of the medium, the physical model that the optical pulse propagates in the medium has been established, which is suitable for the general situation where the optical pulse propagates in the amplifying medium. Using a split-step Fourier method, the propagation state of a chirped optical pulse in the amplifying medium has been numerically simulated, and the influences of the gain dispersion of the medium and the frequency detuning of the pulse on the optical pulse have been discussed emphatically. The results show that, with the amplification and propagation of the ultrashort chirped pulse in the amplifying medium, gain saturation and Kerr nonlinear effect of the medium will cause distortion of the optical pulse. For the optical pulse with a wideband spectrum, gain dispersion will cause the gain narrowing effect, so it is equivalent to a loss mechanism. The frequency detuning of the optical pulse will cause distortion of the pulse, which can be used to weaken the impact of gain saturation, thus reshaping the optical pulse. 相似文献