全保偏非线性偏振环形镜锁模掺铒光纤激光器

研究了基于非线性偏振环形镜锁模的全保偏光纤激光器锁模机制。在非线性偏振环形镜中,用偏振分束器取代传统的非线性放大环形镜锁模激光器中的光纤耦合器,并辅以非互易性元件和增益光纤,作为全保偏光纤激光器中实现稳定锁模的核心器件。构建了一台基于非线性偏振环形镜的掺铒光纤锁模激光振荡器,实现了重复频率75 MHz,时域脉冲宽度141 fs,总输出功率约30 mW的稳定锁模脉冲序列输出。该激光器具有双向输出,且通过调节腔内波片可调节输出功率。此外,对激光器输出功率和重复频率的稳定性进行了评价,在自由运转情况下,1 h内输出脉冲序列的平均功率波动小于0.05%,重复频率的1 s相对稳定度为2.010-8。该结构的全保偏光纤激光器可开机自启动锁模,且环境稳定性高、重复频率较高、脉冲宽度窄,能满足激光测距、激光加工、激光光谱成像、航天等应用对超短脉冲光源的需求。     

红外与毫米波学报J．InfraredMillim．Waves第十三卷年度索引

红外与毫米波学报Ｊ．ＩｎｆｒａｒｅｄＭｉｌｌｉｍ．Ｗａｖｅｓ第十三卷年度索引（一九九四年）关键词索引表面效应一线性和非线性静磁表面波能流的受控偏转特性（１３１）波导－线性和非线性静磁表面波能流的受控偏转特性（１３１）－金属包层平面光波导偏振器和在线单...     

超晶格—反铁磁界面上的非线性TM电磁表面波

研究了反铁磁和超晶格界面上非线性ＴＭ表面波的传播特性，发现超晶格体中液晶层晶轴取向θ为０或π／２时非线性ＴＭ表面波才能在所讨论的界面上存在，导出了非线性ＴＭ表面波的色散关系，分析了非线性ＴＭ表面波的频率特性     

铁磁膜双皱纹波导中非线性静磁表面波的禁带频移

揭示了双皱纹铁磁膜周期波导中静磁表面波的非线性磁化响应导致系统的频率禁带下移和变宽的特性．波导上下表面皱纹间的空间位相差对频率禁带宽度有重要影响，它削弱导波功率的非线性效应，在一定的条件下，它使系统的禁带消失．     

基于PolM的可调谐相位编码信号发生器设计

采用双平行偏振调制器,在不使用任何光或电滤波器的条件下,利用倍频操作在双平行偏振调制器和混合器工作频段内产生相位编码信号。在10Gb/s的编码速率下,仿真实验实现了10~40GHz范围的调谐,结果表明,在光生频率内该相位编码微波信号具有良好的大范围可调谐性能。     

低频激发条件下液体表面波特性及表面波激光干涉测量

对于低频激发的液体表面波,提出了一种激光干涉测量方法,并在实验上观察到了清晰的干涉图样,且干涉条纹定域在一定的空间范围.当表面波激发源频率为几十赫兹时,其表面波参数稳定不变,且表面波反射光所形成的干涉图样稳定不变;而当表面波激发源频率为几赫兹至亚赫兹频段时,表面波为调幅波.表面波反射光所形成的干涉条纹的定域宽度周期性振荡,振荡频率与激发频率相同.理论上导出了调制干涉图样光强度与表面声波之间的解析关系,并得到了干涉条纹间隔与表面波波长、干涉条纹定域宽度与表面波振幅之间的解析关系.     

非线性负折射率材料表面TE电磁波的空间稳定特性分析

针对电磁波在正负非线性材料界面处的传播,研究了两种稳定状态下电磁波的物理特性。理论分析和数值计算表明,该界面处电磁波的传播存在着频率通带,且带宽仅与两种材料的固有属性有关。得出前向表面波和后向表面波均可以在这种非线性导波系统中传播,并且在一定条件下,随着频率的变化,前向表面波和后向表面波可以在两种材料中跃变。推论出两种稳定传播的电磁波场峰值位置随传播功率的变化也能实现在两种材料中跃变,并逐渐向界面靠近,而传播功率较大的稳定态电场峰值几乎靠着界面。     

声表面波调频振荡器

论述了声表面波调频振荡器的原理及设计方法，探讨了有关电路，并制作了中心频率３８０．８ＭＨｚ的声表面波调频振荡器。当调制信号频率区ＤＣ至８００ｋＨｚ变化，幅值为２．５Ｖ时，调频频偏大于５５０ｋＨｚ；当调制信号频率小于或等于２００ｋＨｚ，幅值为１．０Ｖ时，调频非线性失真小于３．５％。振荡器经过温度补偿，温度稳定性优于±１５０ｐｐｍ（－４０℃～＋５０℃）。     

40微秒声表面波色散延迟线的研制

本文是40μs声表面波色散延迟线的研制总结.介绍了设计考虑、性能预计和测试结果.在ST水晶基片上制作了共线型双色散双加权的色散延迟线.器件中心频率30MHz,色散带宽2.5MHz,脉冲压缩旁瓣抑制30dB以上,主瓣-4dB宽度0.6μs,主瓣底部宽度1.6μs,并在-55—+85℃范围满足全部性能指标.最后对匹配问题进行了讨论.     

偏振模色散的分析模型

当光纤通信系统单信道速率到40Gbit/s以上时，偏振模色散的影响已经成为严重影响系统性能的主要因素。对偏振模色散现象的研究通常可采用几种不同的分析模型：琼斯矩阵、斯托克斯空间、耦合非线性薛定谔方程；对这几种分析模型作了详细地介绍，进行了分析和比较，并对40Gbit／s光纤传输系统进行了数值模拟。     

TM Nonlinear electromagnetic waves guided by an inhomogeneous medium

Analytical dispersion relations and the power flow expression for TM (polarized) nonlinear electromagnetic surface waves propagating along the interface of an inhomogeneous and dielectric nonlinear media have been investigated theoretically. An inhomogeneous dielectric cover has the dielectric permittivityε=a+bz, which is contacted with a strongly nonlinear Kerr like layer. The existence conditions for these waves to be propagated are studied. These waves have no counterpart in the linear isotropic regime. The power flow versus the wave index, and the consequence interface nonlinearity might be evaluated for a variety of inhomogeneity parameters, which are found to be inhomogeneity dependent, and could lead to optical hysterisis and bistability.     

Calculation of the propagation constants and fields of polarized electromagnetic TM waves in a nonlinear anisotropic layer

Propagation of polarized electromagnetic TM waves through a nonlinear homogeneous nonmagnetic dielectric layer located between two homogeneous isotropic half-spaces is considered. The dispersion equation is derived for the propagation constants (eigenvalues) of waves in the layer. The propagation constants for nonlinear and linear media in the layer are compared. The propagation constants and fields (eigenfunctions) are calculated.     

TM waves in nonlinear saturable thin films: a multilayered approach

The dispersion of guided TM (transverse magnetic)-polarized waves in a thin nonlinear saturable film bounded by linear media is investigated. The film is assumed to be isotropic with both of the electric field components contributing to its dielectric function. The variation of the wave effective index with the guided power and also with the surface magnetic field intensity is obtained. Different mechanisms giving rise to the nonlinearity of the film are shown to result only in small quantitative differences in the dispersion behavior. A recursive scheme for solving the nonlinear wave equation within the film is fully described. The scheme relates to the saturable dielectric function used and its based on the stratification of the film region into a large number of linear sublayers     

Propagation of electromagnetic waves in a nonlinear metamaterial layer

Propagation of electromagnetic TE waves in a nonlinear dielectric layer with generalized Kerr’s nonlinearity is considered. The layer is located between two isotropic nonmagnetic semi-infinite media with constant electrodynamic parameters. The dispersion equation for the eigenvalues of the problem (propagation constants) is derived. The behavior of dispersion curves is qualitatively analyzed. Propagation of waves in a nonlinear metamaterial is studied.     

Magnetostatic surface waves in a ferrite/dielectric/metal-strip-grating structure

The dispersion relation for magnetostatic surface waves in a ferrite/dielectric/metal-strip-grating structure is obtained. It is shown that dispersion of magnetostatic surface waves must be qualitatively the same as in a ferrite/dielectric/metal structure, while the slope of the dispersion curve in the region of backward magnetostatic waves existing in a ferrite/dielectric/grating structure (and in a ferrite/grating structure in particular) is considerably higher than the slope of this curve corresponding to a ferrite/dielectric/metal structure. It is found that this phenomenon can be explained by the dependence of the grating’s shielding capability on the wave number of magnetostatic surface waves. A grating shielding parameter is introduced and dependences of this parameter on the wave number that can be used to explain the phenomena observed in the experiment are determined.     

New nonlinear magnetostatic surface waves in a ferromagnetic (YIG)

The general propagation characteristics of magnetostatic surface waves guided by a single interface of a semi-infinite nonlinear dielectric cover and a ferromagnetic substrate (YIG) have been derived. The nonlinear dielectric cover has intensity dependent refractive indices. The magnetostatic approximation is considered and retardation is ignored in describing the electromagnetic fields in the structure. The used magnetostatic approximation is leading to new waves and might be called nonlinear magnetostatic surface waves. The propagation of these waves is non-reciprocal in contrast to the linear magnetostaic surface waves, which had been only found in the negative direction of propagation.     

Unified nonlinear waveguide dispersion equations without spuriousroots

Analysis is made of the behavior of transverse electric (TE) waves in an optical waveguide comprising a nonlinear film sandwiched between two semi-infinite linear media. Unified expression of dispersion equation is presented for all different nonlinear waveguides, which could have any possible linear dielectric profile, and comprise a nonlinear film with either self-focusing or self-defocusing nonlinearity. This new dispersion equation offers simple numerical calculations and avoids the appearance of spurious roots     

A surface wave interpretation for the resonances of a dielectric sphere

The calculated radar and bistatic cross sections of dielectric spheres exhibit numerous resonances when plotted versus frequency. These resonances may be related to the excitation of electromagnetic eigenvibrations of the sphere, with resonance frequencies calculable from a characteristic equation. It is shown that the resonances may be viewed as originating from families of circumferential (surface, or creeping) waves that are generated during the scattering process; at each eigenfrequency of the sphere, one of these surface waves matches phases after its repeated circumnavigations around the sphere, with the ensuing resonant reinforcement leading to the given scattering resonance. This mechanism explains the existence of electromagnetic eigenvibrations of a general smooth dielectric object; for the case of a sphere, it is shown that the surface waves suffer a phase jump ofpi/2at each of their two convergence points. We calculated numerical values of the eigenfrequencies of dielectric spheres, and obtain dispersion curves for the phase velocities of the surface waves.     

Terahertz and Infrared Surface Wave Beams and Pulses on Gyrotropic,Nonlinear and Metamaterial Interfaces

This work is devoted to theoretical study of surface plasmon polariton propagation on metal or metamaterial – dielectric interfaces where media can possess optical or magnetooptical activity or cubic nonlinearity. On the interface of gyrotropic media surface wave changes its polarization and profile as well as in case of interface of media with cubic nonlinearity. Surface wave propagation constant can be modified by magnetization leading to magnetooptical intensity effect. The properties of plasmons in gratings are also considered including excitation, dispersion and existence of various types of modes. The theory of surface wave and pulsed beam diffraction in gyrotropic, nonlinear and layered media is developed. We also present waveguide for surface waves based on layered metamaterial – dielectric interfaces suppressing diffraction spreading.     

强双折射色散缓变光纤中偏振方向矢量调制不稳定性

利用光脉冲在非线性双折射光纤中传播时所遵守的相干耦合非线性薛定谔方程,研究了强双折射色散缓变光纤中偏振方向与双折射轴成任意角度时,在反常色散区和正常色散区所产生的调制不稳定性.结果表明：在反常色散区对于任意的偏振角和任意输入功率的光脉冲都产生调制不稳定性,正常色散区存在着不稳定区域和稳定区域,对应不同的不稳定区域输入临界功率不同,脉冲有不同的增益谱.并且,给出了调制不稳定性增益谱随传输距离和偏振角的变化关系.