Analysis of Planar Dielectric Waveguide with Mirror-Conjugate Chiralities in the Core and the Cladding

The propagation characteristics of a planar waveguide with mirror-conjugate chiralities filled in the core and the cladding (mirror-conjugate chirality waveguide) are presented. The effects of chirality on cutoff, dispersion and field distribution characteristics of the waveguide are studied. The results show that the waveguide with desired features can be made by appropriately selecting the chiralities of the core and the cladding, because the core chirality and cladding chirality have different influences on waveguide propagation characteristics.     

Analysis of Planar Dielectric Waveguide with Chiral Cladding

The propagation characteristics of a planar waveguide with chiral media filled in the cladding are presented. The effect of chirality on cutoff, dispersion and field distribution of the waveguide are studied. The results show that the cladding chirality may lead to a single-mode operation in the planar waveguide.     

Analysis of Circular Dielectric Waveguide with Chiral Cladding

The propagation characteristics of a circular dielectric waveguide with chiral media filled in the cladding are investigated. The relation between the cutoff frequency and the chiral admittance, the dispersion curves for some modes with different angular mode numbers and the transverse distribution of fields are presented. Some new features different from the ordinary circular dielectric waveguide are resulted. The results show that the cladding chirality may lead to a single-mode operation in the circular dielectric waveguide.     

Electromagnetic waves in uniaxial anisotropic chiral waveguides in magnetized plasma

The characteristics of guided modes in circular waveguides of a uniaxial anisotropic chiral core and a cladding filled with anisotropic plasma are presented. The cladding region is assumed to be infinitely extended with an external applied magnetic field oriented along the direction of propagation in the waveguide. The characteristics equation for the modes in this waveguide are obtained. The variations of the propagation properties with the plasma parameters, chiral parameters, and the cyclotron frequency of plasma have been investigated. Particularly, the effects of the chirality and the cyclotron frequency of plasma on the magnitude and orientation of the energy flux of the guided modes for three kinds of uniaxial anisotropic chiral media have been numerically investigated. Comparisons of the computed results of the presented formulations with published results for some special cases confirm the accuracy of the presented analyses.     

Analysis of Circular Chiral Dielectric Waveguides

The general eigenequations and the field expressions for circular waveguides containing chiral material in both the core and the cladding are given in a simple formulation. The results indicate that there are two types of field distribution which is related to the operating wavelength and chiral admittance. When the chiral admittance is larger than a critical value, the fields of one kind of circularly polarized wave in the core become exponentially-like damping in the transverse direction. Based on the eigenequations, the characteristics of a circular waveguide with chiral medium filled in the core are investigated. The relation between the cutoff frequency and the chiral admittance, the dispersion curves for some modes with different angular mode number and the transverse distribution of fields are presented. Some features different from the ordinary circular waveguide are resulted.     

Existence of negative dispersion and band gap in a helically inner cladded annular circular waveguide

Helical waveguide, a different type of waveguide structure, has been considered for analysis of modal dispersion characteristics. This paper deals with the study of a new type of annular waveguide, in which the inner cladding is made by the helical windings i.e. sheath helix and the outer cladding is as usual simple step-index cladding. Using vector approach, the general characteristic equation for the proposed waveguide has been derived. The modal dispersion characteristics for the lowest order modes for different pitch angles and thickness are determined and analyzed. We have found that there is an existence of the negative dispersion curve in the helically inner cladded annular circular waveguide. It means that the inner cladding is responsible for the negative dispersion which is generally obtained in a photonic band gap.     

平面波导衍射特性分析

从电磁波的瑞利－索末菲标量衍射积分公式出发，利用罗兰圆结构特殊的光学性能，在平面坐标系中简化标量衍射积分公式，推导出横截面折射率阶跃分布的平面波导端口衍射场分布的计算公式，并导出常用的对称结构介质平面波导和金属平面波导端口衍射场的空间频谱，阐明平面波导端口衍射场就是驻波衍射场的本质。     

克尔型非线性薄膜波导的TE模

对于芯区为克尔型非线性介质，覆盖层和衬底为线性介质的平板波导，用Ｋｒｙｌｏｖ－Ｂｏｇｏｌｉｕｂｏｖ－Ｍｉｔｒｏｐｏｌｓｋｙ的渐近法导出了色散方程及场分布的二阶近似数学表达式，计算量大为减少且结果精确。给出了对称和非对称情况的典型实例。     

A theoretical study of the modal dispersion characteristics of an annular circular waveguide with helical winding as the outer cladding

In this present communication, we introduce a new type of annular optical waveguide whose outer cladding is made of sheath helix. The sheath helix is made up of the dielectric material of lower refractive index than the core materials. Using vector approach, the general characteristic equation for the proposed waveguide has been derived. The modal dispersion characteristics for the lowest-order modes for different pitch angles are determined and analyzed. We observe that there is no effect of pitch angles on dispersion curve nearly up to 89° but drastic change is observed at 90° and above pitch angle. On comparison of helically inner cladded annular circular waveguide, we have found that there is not the existence of the negative dispersion curve and photonic band gap in the helically outer cladded annular circular waveguide. It means only the inner cladding is responsible for the negative dispersion as well as photonic band gap. There is no effect of the outer cladding.     

Uniform Core Field in Symmetrical Planar Waveguides and Circular Fibers with Nonlinear Claddings

1　ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｋｅｙｃｏｎｃｅｐｔｏｎｗｈｉｃｈａｌｌｎｏｎｌｉｎｅａｒｇｕｉｄｅｄｗａｖｅｏｐｔｉｃａｌｄｅｖｉｃｅｓ[1～ 3] ａｒｅｂａｓｅｄｉｓｔｈａｔｔｈｅｌｏｃａｌｉｎｔｅｎｓｉｔｙｏｆｔｈｅｇｕｉｄｅｄｗａｖｅｃｏｎｔｒｏｌｓｔｈｅｐｒｏｐａｇａｔｉｏｎｗａｖｅｖｅｃｔｏｒ ,ｔｈａｔｉｓ,ｔｈｅｆｉｅｌｄｐｒｏｆｉｌｅａｎｄｐｒｏｐａｇａｔｉｏｎｃｏｎｓｔａｎｔｃａｎｂｅｃｏｍｅ ｐｏｗｅｒｄｅｐｅｎｄｅｎｔｗｈｅｎｏｎｅｏｒｍｏｒｅ[4～ 6] ｏｆｔｈｅｌａｙｅｒｓａｒ…     

非线性包层多量子阱波导的TE波

给出用以分析非线性包层多量子阱波导ＴＥ模光学非线性与双稳性的理论公式与计算方法。指出用均方根等效折射率法解本征方程是有效的简化方法。用本文方法分析了模折射率对波导总功率的依赖关系,芯区功率与总功率之间的双稳性以及模场分布与模折射率的关系。讨论了波导参数对光学非线性、双稳性及模场的分布的影响。     

一种高品质中空金属光波导

讨论了高品质中空金属光波导的工作原理及其制作工艺，制备了以金和银作为波导材料的中空波导管，并对空芯以及充入不同透明液体的液芯波导的透光特性进行了测试，结果表明：与中空介质波导相比，中空金属波导具有光传输损耗低，透过率对波导弯曲与失调不甚敏感等优点；而液芯金属波导的透光效率与透明材料的折射系数无关。文中描述了在特定波段内“中空光纤”的原理，并报道了Ｈｅ－Ｎｅ和ＣＯ２激光在中空金壁波导传输的实验结果。     

The study of multilayer planar optical waveguide structure with nonlinear cladding

A novel method for analyzing the multilayer and multibranch optical waveguides with nonlinear cladding is presented. This method can also be used to analyze the multiple-quantum-well (MQW) waveguide structure. Numerical simulation results show that our analyses are reasonable.     

Modal analysis and cutoff frequencies of a doubly clad plasma loaded waveguide having a lemniscates of Bernoulli-type core cross-section

The modal dispersion characteristics of EM waves in a new unconventional plasma loaded doubly clad waveguide having a shape of the lemniscates of Bernoulli-type core cross-section have been studied analytically. The proposed waveguide has three parts namely the core with slighter high index, the inner cladding with plasma and the outer cladding with air. Now using the necessary orthogonal coordinates for the proposed structure and imposing the boundary conditions under the weak guidance condition, the modal characteristics equation has been obtained considering variations in plasma width and plasma frequency, the dispersion curves and cutoff frequencies have been obtained and presented in this paper. It is noted that as the width of plasma layer increases, the cutoff frequency also increases considerably in all considered cases. This shows that using plasma width as a new parameter we can control any particular mode on our wish.     

用转移矩阵法研究LNN型非线性平面光波导

用转移矩阵法数值分析了芯区和衬底为非线性介质、覆盖层为线性介质结构平面光波导的传播特性,包括TM的模场分布和功率与有效折射率之间关系的分析.解析地表达了模式本征方程和功率分布,对非线性介质中电场强度与介质非线性系数的关系进行了研究.计算结果表明,TM的模场分布和功率与有效折射率及介质的非线性系数有关.     

Study of in-line single-mode optical fiber polarizer

The theoretical calculation method of multilayer metal-clad planar optical waveguide presented by Y. YAMAMOTO is greatly improved and transplant into the optical fiber and a suitable waveguide model of in-line single-mode optical fiber polarizer is set up to study its characteristics, the theorical analyses are in accordance with the experimental re suits. The polarizer whose extinction ratio is more than 30 dB at 0.633μm wavelength with an insertion loss of 0.5 dB is formed by grinding off the cladding on one side of a single-mode fibre and evaporating metal onto the polished durface in our Lab.     

波导厚度变动、偏振变动以及折射率变动脱敏高分子宽带耦合器设计

针对高分子光波导在制造工艺中波导芯厚度难以控制、芯层和包层的折射率差变动时的随机性以及材料各向异性引起的偏振态依赖性等实际问题,提出了采用抗波导芯厚度误差、抗折射率差变动和抗偏振变动的宽带波导耦合器回路结构的解决方案,给出了设计的理论和方法。在实测数据的基础上,进行了带宽为120nm的3dB氟化聚酰亚胺波导耦合器设计。由该器件的三维BPM仿真结果表明,在上述带宽上,波导芯厚度的变动范围为7～8μm、相对折射率差变动范围为0 24%～0.30%,两个正交偏振态都具有(50±2.0)%功率输出比的良好特性。     

Field Analysis of a Metal-Coated Planar Waveguide with Chiral Core

Eigenequations for a metal-coated planar chiral dielectric waveguide and a mirror-conjugate planar chiral dielectric waveguide are derived. The eigenequations are given in simple formulations. The results indicate that the perfect conductive (or magnetic) boundary can produce mirror-conjugate of chiral media and the left-handed and right-handed circularly polarized modes couple with each other due to the conductive boundary. The propagation characteristics of a metal-coated planar waveguide with chiral core are presented. An interesting phenomenon is observed that the field distributions vary with respect to the operating wavelength.     

Design and analysis of nano-deep corrugated waveguide grating-based dual-resonant filters in visible and infra-red regions

A theoretical analysis of nano-deep corrugated long-period waveguide gratings on a SU-8 polymer-based channel waveguide with NOA61 optical epoxy coated upper- and lower cladding is presented. The transmission spectra of the gratings show strong rejection bands both at visible (at wavelength region of 450?460 nm) and infra-red (at wavelength region of 1530?1540 nm) regions when a grating period of ?68 μm with optimized grating tooth height is considered. Phase-matching graphs are studied to find the relationship between resonance wavelength and grating period. These results show that the grating parameters significantly affect the characteristics of transmission spectra as well as the resonance wavelength of the grating. Long-period waveguide grating-based band pass filter made by use of same polymer materials are also designed and analyzed. These types of waveguide grating-based filters can widely be used for visible and infra-red wavelength sensing applications.     

非线性光波导中基波和二次谐波的模场分布研究

非线性波导是一种重要的光量子器件。采用马卡梯里近似,可以近似描述波导的模场分布特征。针对ee-e准相位匹配的周期极化铌酸锂波导,分析波长为1 064 nm的基波和532 nm的二次谐波的基模模场分布。结果表明:如果波导为嵌入型正方形波导,基波和二次谐波的光斑基本为圆形,基波场分布范围较大;在截面正方形边长为5 μm并且芯区比包层折射率略高0.02时,波导就能将两种光波场基本约束在芯区中,但是这种波导边长为0.5 μm时约束能力就变得很差;如果采用芯区与包层折射率差别较大的波导,芯区边长为0.5 μm就可以将两种场分布基本约束在芯区中。结果对分析其他类型的非线性波导的模场分布具有指导意义。