基于Saleh模型的DRSS信道建模与仿真

对DRSS信道URE链路进行建模仿真,采用Saleh模型描述DRSS信道URE链路中HPA的非线性特性。通过仿真8PSK、方型16QAM、星型16QAM调制信号并经过DRSS URE非线性信道后的非线性ISI特性、频率特性、星座图和误码特性,分析了信道非线性特性对通信系统性能的影响。     

光子晶体光纤的非线性特性研究

较全面地介绍了有关光子晶体光纤非线性特性最新的理论和实验进展,其中包括关于两种基本类型的光子晶体光纤非线性特性的各种实验现象及理论分析,并探讨了基于非线性特性的全光纤器件的广阔应用前景。     

通信系统的非线性特性研究

本文阐述了通信系统中的非线性特性及其分类,并根据Volterra级数法定量地描述和分析了通信系统中非线性响应特性及其影响.最后从工程的角度提出了减小系统非线性特性及其干扰的一些具体措施,为今后解决通信系统中的非线性干扰问题提供了相应的理论参考.     

数字微波通信系统中的非线性

本文简要分析数字微波通信系统中非线性的来源，变化规律及其对系统传输特性的影响，介绍了对抗系统非线性的几种措施，提出了一种可用于计算机模拟的非线性分析方法，还讨论了系统非线性特性的测试，以及有关非线性的几个重要概念。     

CdTe和CdTe/CdS量子点的量子尺寸效应

利用水热法合成了三种不同尺寸的单核CdTe量子点和核壳CdTe/CdS量子点。应用Top-hat Z-scan技术在纳秒、皮秒、飞秒激光脉冲作用下研究了三种不同尺寸单核CdTe量子点的非线性吸收特性。实验结果表明:在不同激光脉冲作用下三种不同尺寸的CdTe量子点的非线性吸收特性均表现为饱和吸收,并且均呈现出随着量子点尺寸的减小,其非线性吸收特性增大的趋势。为了进一步研究量子点尺寸的变化对非线性吸收特性的影响,又在飞秒激光脉冲作用下研究了核壳CdTe/CdS量子点的非线性吸收特性;随着包壳时间的增加,壳层厚度增加,量子点尺寸增加,其非线性吸收特性呈减小趋势,并且核壳CdTe/CdS量子点的非线性吸收特性明显优于单核CdTe量子点;分析讨论了单核CdTe量子点与核壳CdTe/CdS量子点的非线性吸收特性和量子尺寸效应机制,实验结果表明合成的量子点样品均具有良好的量子尺寸效应。     

半导体纳米粒子Bi2S3和NiS的非线性吸收特性

测量了两种纳米粒子Bi2S3和NiS的光限幅特性和非线性光学响应，测量了非线性吸收特性，数值模拟计算了Bi2S3的非线性吸收系数β≈9cm/GW, NiS非线性吸收系数β≈8cm/GW.     

半导体纳米粒子Bi2S3和NiS的非线性吸收特性

测量了两种纳米粒子Bi2S3和NiS的光限幅特性和非线性光学响应,测量了非线性吸收特性,数值模拟计算了Bi2S3的非线性吸收系数β≈9cm/GW,NiS非线性吸收系数β≈8cm/GW.     

半导体纳米粒子Bi2S3和NiS的非线性吸收特性

测量了两种纳米粒子Bi2S3和NiS的光限幅特性和非线性光学响应,测量了非线性吸收特性,数值模拟计算了Bi2S3的非线性吸收系数β≈9cm/GW,NiS非线性吸收系数β≈8cm/GW.     

2D材料和准2D材料的非线性光学特性及应用

二维(2D)材料具有独特的结构和光电特性,在能源、环境、高性能光电传感等方面都有非常重要的应用。2D材料的非线性光学特性及应用是研究者广泛关注的热点研究领域。从2D材料的制备方法、晶体和能带结构、非线性光学特性研究等方面对2D材料的研究进行了简单回顾。非线性纳米晶自组装或复合薄膜是另一类重要的非线性材料。考虑到这类材料的宏观2D特性和论述内容的连贯性,将非线性纳米晶自组装或复合薄膜归于准2D材料,并对其非线性光学特性和应用等也进行了简单介绍,作为对非线性光学材料研究的补充。     

中心金属原子对萘酞菁化合物激发态的光学非线性增强效应

应用Z-扫描技术对比研究了萘酞菁铅和萘酞菁钯化合物在波长为532 nm纳秒激光脉冲作用下的三阶非线光学特性。实验结果表明,两种萘酞菁化合物均显现出较强的非线性吸收特性(反饱和吸收)和非线性折射特性(自聚焦)。理论拟合得出萘酞菁铅和萘酞菁钯的非线性吸收系数分别为6.5410-10 m/W和3.9010-10 m/W;非线性折射系数率n2分别为1.6810-10 esu和8.0410-11 esu;二阶分子超极化率系数分别为3.4410-28 esu和2.5710-28 esu,CS2二阶分子超极化率系数为4.3210-33 esu;两种萘酞菁化合物的二阶分子超极化率强于CS2近5个数量级。实验结果表明,萘酞菁铅化合物具有较强的非线性吸收和非线性折射特性,且大于萘酞菁钯化合物的光学非线性特性是由于萘酞菁铅化合物的重原子效应提高了其光学非线性特性。     

Metal-induced efficient enhancement of nonlinear optical response in conjugated azo-based iminopyridine complexes

The nonlinear optical (NLO) properties of conjugated azo-based iminopyridine complexes with zinc and silver metal cations were studied. The processes of second and third harmonic generations in guest-host polymeric films were investigated and NLO parameters were extracted. Obtained second and third order NLO susceptibilities of zinc containing complex exceeds the latter of silver containing one. Using the Z-scan technique the NLO refractive index, NLO absorption coefficient, second order hyperpolarizability and NLO absorption cross section for the azo-based iminopyridine zinc (II) and silver (I) complexes were obtained and analyzed. Estimated nonlinearity/loss figure of merit of these complexes show promise for optical device applications.     

Second-harmonic generation from CuInSe2 thin films:influence of the substrate-epilayer lattice mismatch

We investigate the second-order nonlinear optical (NLO) properties of tetragonal chalcopyrite-structure CuInSe₂ thin films using optical second-harmonic generation at a fundamental wavelength of 790 nm. An approximate doubling of the second-order optical nonlinearity of the CuInSe₂ thin films is achieved through changing the substrate from GaAs(001) to In_0.29Ga_0.71As(001), thereby reducing the lattice mismatch from 2.2% to 0.2%. This observation suggests that minimizing the lattice mismatch is a key requirement for the growth of high-quality NLO active chalcopyrite structure thin films and is in contrast to some other NLO active thin-film systems     

Highly Efficient and Thermally Stable Electro‐Optical Dendrimers for Photonics

After a brief review on electro‐optical (EO) polymers, the recent development of EO dendrimers is summarized. Both single‐ and multiple‐dendron‐modified nonlinear optical (NLO) chromophores in the guest–host polymer systems showed a very significant enhancement of poling efficiency (up to a three‐fold increase) due to the minimization of intermolecular electrostatic interactions among large dipole moment chromophores through the dendritic effect. Moreover, multiple NLO chromophore building blocks can also be placed into a dendrimer to construct a precise molecular architecture with a predetermined chemical composition. The site‐isolation effect, through the encapsulation of NLO moieties with dendrons, can greatly enhance the performance of EO materials. A very large EO coefficient (r₃₃ = 60 pm/V at 1.55 μm) and high temporal stability (85 °C for more than 1000 h) were achieved in a NLO dendrimer (see Figure) through the double‐end functionalization of a three‐dimensional phenyl‐tetracyanobutadienyl (Ph‐TCBD)‐containing NLO chromophore with thermally crosslinkable trifluorovinylether‐containing dendrons.     

光学高分子薄膜纳米结构与性能关系的探讨

应用AFM及力曲线的统计方法(forcecurvemethod)和Tapping/Phase功能,比较系统地研究了Glass/ITO基底上旋涂厚度为5μm的非线性光学功能高分子薄膜。结果发现,不同基底对于薄膜结构及分子构象没有明显影响。客体分子(molecule-2)在常温条件下能够以氢键的方式镶嵌在主体高分子(molecule-1)链上的—OH官能团周围和相邻的分子链间,形成特征的纳米级带状结构。ITO基底上非线性光学功能高分子薄膜在160～180℃条件下和经3000V强电场极化后,客体分子和主体高分子不同程度地进行了化学交联反应,生成新的非线性光学高分子;薄膜的微观结构由常温时的带状结构变为纳米环状结构,膜表面呈现出均匀平滑的表面形貌,并获得了理想的电光性能信号。分子键合类型的变化使得薄膜的组分发生了变化,并引起了薄膜的微观结构的改变。力曲线的统计方法和Phase的相关信息为此提供了重要证据。     

1D Van der Waals Polymers with Nonlinear Optical Performance Approaching Theoretical Upper Limit

Nonlinear optical (NLO) materials are of great importance for applications in lasers, atomic clocks, free-space communication, etc. Herein, inspired by the recent prediction of excellent second harmonic generation (SHG) performance in van der Waals (vdW) materials with 1D building blocks, 14 new NLO materials are found from 244 bulk crystals constructed with 1D polymers using high-throughput first-principles calculations. Nearly half of the new NLO materials exhibit superior NLO performance with SHG susceptibilities approaching the theoretical upper limit. The 2D form of 11 candidates inherits the NLO property covering UV, visible, and infrared regions. Bader charge analysis reveals that the SHG susceptibility is determined by the charge difference of ions on the chains. Finally, it is proposed that superior NLO materials can be found in materials with proper bandgaps and large charge differences on the chains. This work not only screens out candidates with outstanding NLO performance in vdW materials with 1D building blocks but also provides a guideline for the search and design of NLO vdW 1D polymer patterns with excellent NLO properties.     

Polymer‐Based Devices for Optical Communications

Polymers are emerging as new alternative materials for optical communication devices. We developed two types of polymer‐based devices for optical communications. One type is for ultra high‐speed signal processing that uses nonlinear optical (NLO) polymers in such devices as electro ‐optic (EO) Mach‐Zëhnder (MZ) modulators and EO 2×2 switches. The other is for WDM optical communications that use low‐loss optical polymers in such devices as 1×2, 2×2, 4‐arrayed 2×2 digital optical switches (DOSs) and 16×16 arrayed waveguide grating (AWG) routers. For these devices, we synthesized a polyetherimide‐disperse red 1 (PEI‐DR1) side chain NLO polymer and a low‐loss optical polymer known as fluorinated polyaryleneethers (FPAE). This paper presents the details of our development of these polymeric photonic devices considering all aspects from materials to packaging.     

Fabrication and characterization of photonic crystal-based symmetric Mach-Zehnder (PC-SMZ) structures based on GaAs membrane slab waveguides

We have experimentally demonstrated two- dimensional (2-D) photonic crystal (PC) waveguides (WGs) such as straight, bent, Y-branch, directional coupler (DC), and quantum dots (QDs)-based nonlinear optical (NLO) WGs using a GaAs air-bridge membrane with triangular-lattice line-defect WGs. These WGs are necessary for a 2-D PC-based symmetric Mach-Zehnder (PC-SMZ) type ultrafast all-optical switch. Experimental results on the clear observation of the optical interference at the Y-junction DC, nonlinearity-induced phase shift at the NLO waveguide, and transmission spectra in the total PC-SMZ WG configuration will be addressed, as well as measured results on each WG element.     

测量NLO聚合物薄膜光波导传输损耗的方法

本文综述了测量非线性光学（NLO）聚合物薄膜材料光传输损耗的4种常用的方法及原理,并分别给出了典型的实验装置结构图,最后对这些方法的特点进行了比较。     

Third‐Order Nonlinear Optical Response of Gold‐Island Films

Films of gold nanoscaled islands with thicknesses ranging between 0.5 and 15 nm were prepared by thermal evaporation onto untreated and aminosilane‐pretreated glass substrates. Post‐deposition annealing was found to modify the morphological characteristics of the islands (e.g., average island area and height, inter‐island distance, etc.), resulting in changes of the localized surface plasmon resonance (SPR) characteristics and, therefore, modifying the nonlinear optical (NLO) response of the films. The NLO response of both unannealed and annealed (20 h at 200 °C) films was studied by means of the optical Kerr effect (OKE), using 35 ps, 532 nm laser excitation, while measurements performed by means of the Z‐scan technique allowed for the determination of both the nonlinear refraction and absorption characteristics of the films. The results are discussed and compared with other reports.