Purely Longitudinal Guidance in Dielectric Waveguide Array

Rigorous analysis shows that independent longitudinally guided TE and TM modes are possible in dielectric waveguide array (DWA) as a two dimensionally periodic medium. Especially, purely longitudinally guidance is also possible and investigated in detail.     

Longitudinal Wave Propagation in Dielectric Waveguide Array

Based on the established rigorous theory for two-dimensionally periodic (2DP) medium, Longitudinal propagation in Dielectric Waveguide Array (DWA) was analyzed in detail. Firstly, given longitudinal wave vector (k _z), Brillouin dispersion relations between transversal wave vectors were analyzed. Interactions between space harmonics were also studied. Secondly, on condition that transversal wave vector k _x equaled k _y, dispersion relations between longitudinal and transversal wave vectors were analyzed in detail. Because of interactions between space harmonics increasingly getting stronger with k _z or modulation coefficients increasing, stop-bands could be distinctly displayed and thus longitudinal propagation in DWA could be comprehensively analyzed. The applications about longitudinal propagation in DWA were also discussed.     

Characteristic Electromagnetic Fields in Dielectric Waveguide Array

Based on the modal solution of one dimensionally periodic structure with piecewise uniform dielectric constant distribution, characteristic solutions for two dimensionally Dielectric Waveguide Array (DWA) are rigorously formulated. By satisfying periodic boundary conditions in the interfaces inside a unit cell, semi-closed-form dispersion relation for DWA can be established. Numerical results are presented and compared with a previous method. A class of guidance and radiation problems can be solved with much more simplicity and accuracy.     

Transverse Propagation in Dielectric Waveguide Array

Transverse propagation eigen equations for dielectric waveguide array (DWA) are derived and eigen solutions can be uncoupled into TE and TM modes. Numerical results shows that much stronger space harmonic interaction exists so that a series of interesting physical effect of canonical two-dimensionally periodic (2DP) medium can obviously be observed in DWA and related devices can be predicted, designed and realized much easier.     

The Convergence of the Eigen Equation for Dielectric Waveguide Array

The eigen equation for Dielectric Waveguide Array (DWA) established by [1] was discussed. The convergence of the eigen equation was also analyzed in detail. Numerical results for a particular rectangular DWA was presented. Compared with those obtained by previous different ways, faster convergence for the eigen equation was reached easily. The characteristics of the eigen equation for DWA was particularly useful in computer propramming and engineering.     

Rigorous Analysis of Electromagnetic Wave Propagation in Cylindrical Dielectric Waveguide Array

Cylindrical Dielectric Waveguide Array(CDWA) should be considered as a kind of two-dimensionally periodic(2DP) medium. Based on the established rigorous theory for 2DP medium, a great amount of numerical results for CDWA were presented. Wave propagation in CDWA was analyzed in detail in this paper. Firstly, given the longitudinal wave vector (k _z=0), Brillouin dispersion relations between transverse wave vectors were analyzed when modulation coefficients or the rate of different dielectric areas in a unit cell varied. Interactions between space harmonics were also studied. Secondly, when the area of dielectric cylinder in the unit cell varied within a given range, CDWA dispersion relations were compared with Rectangle Dielectric Waveguide Array's, some interesting conclusions were obtained.     

Visualization of Isofrequency Contours of Strongly Localized Waveguide Modes in Planar Dielectric Structures

An experimental method has been proposed to study the dispersion properties of optical surface and waveguide modes in planar structures. An experimental setup involves a microscope with a high numerical aperture objective and a hemispherical solid immersion lens made of zinc selenide in contact with the sample surface. The reflection from the sample is detected in the back focal plane of the system. Such a configuration makes it possible to study strongly localized states with an effective refractive index up to 2.25 in the visible and near infrared spectral ranges. For a thin silicon layer deposited on a glass substrate, the possibility of visualization of isofrequency contrours with polarization resolution and the reconstruction of dispersion of waveguide modes depending on the direction of their propagation has been demonstrated.     

Hybrid Modes in a Square Corrugated Waveguide

By using two scalar eigenfunctions, electric and magnetic fields in the rectangular (or square) corrugated waveguide are analyzed. In a rectangular corrugated waveguide, the boundary conditions on two corrugated and two smooth walls can be satisfied to excite the hybrid mode. In a highly oversized waveguide where the wavelength of dominant mode is close to that in vacuum, two smooth walls can be exchanged with the corrugated walls because the boundary condition at those walls is satisfied approximately. The replacement is possible due to almost no penetration of the electromagnetic fields into the gap of the replaced walls when the direction of main electric field is parallel to the gap of replaced walls. This characteristic enables us to rotate the polarization of the hybrid mode in the oversized square waveguide with all four corrugated walls and is applicable to the remote steering antenna for electron cyclotron heating in the ITER.     

掺铒磷酸盐玻璃波导放大器的特性研究

研究了掺铒磷酸盐玻璃波导放大器的特性。利用重叠因子将980nm光抽运的掺铒玻璃波导放大器四能级模型的速率-传输方程进行化简,在考虑上转换效应和放大自发发射的情况下．利用数值模拟的方法,得到了掺铒玻璃波导放大器的增益与Er^3 离子浓度、抽运功率、波导长度等参量之间的关系曲线;同时模拟出放大自发发射曲线并与实验测量结果进行比较。结果表明在考虑上转换效应和放大自发发射的情况下,理论结果和实验测量结果是一致的。同时看到,选择合适的铒离子浓度是制作掺铒玻璃波导放大器的关键;并且为了全面发挥掺铒玻璃波导放大器的性能,需要抽运功率、波导长度等各个参量配合起来。     

多层平面介质波导辐射模

介绍一种精确计算多层平面介质波导归一化正交辐射模的方法，在全辐射模的情况下，为了保证模的正交性，给出了准奇模和准偶模的确定方法，这此方法地计算机编程，为模传播法的建立和实际应用奠定了基础，本文最后给出几个应用的实例。     

Lognormal Modes of Dielectric Optical Waveguides

It is shown that, at a critical point where the effective refractive index of a mode coincides with the bulk index of a cladding region, optical waveguide modes exhibiting a lognormal feature are supportable for a hyperlongrange refractive-index profile. As a typical example of waveguides that support lognormal modes a parabolic-index core surrounded by a depressed-index cladding is presented.     

Field Patterns of the TE Modes in Ridge-Trough Waveguide

A single-ridge waveguide with a symmetrical longitudinal trough, designated as a ridge-trough waveguide has been used as a transition in a V-band (50-75 GHz) wafer probe recently. In this paper, the field patterns for the dominant TE mode and the first higher TE mode in ridge-trough waveguide with different configurations are presented by finite element method. The field patterns in this paper have important values for us to understand the transmission characteristics of ridge-trough waveguide, and will be of practical significance in designing ridge-trough waveguide components in microwave and millimeter wave engineering.     

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.     

The Influence of the Fluctuation Amplitude on the Probe Characteristic

The time-averaged probe current is calculated by using a sampling method for sinusoidal and sawtooth-like oscillations of the space potential. The effect of oscillations on the measured plasma parameters obtained with the aid of the single probe method, double probe method and the method of the second derivative of the probe characteristic is discussed, with the electron saturation current being taken into account. In the ion current the values r_p/λ_D, λ/r_p and M_i characterizing the working regime are varied. The calculated results are checked by corresponding measurements in a beam generated plasma.     

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.     

Dispersion Characteristics of Dielectric Loaded Multiple V-Ridge Waveguide

A new kind of V-ridge waveguide is presented in this paper. The transmission problem is solved by edge element for the first time. The field patterns of the waveguide with single, double and triple V-ridge for different values of dielectric constant have been presented. Variations of the cutoff wavelength, single-mode bandwidth with the ridge dimensions for different values of dielectric constant are investigated in detail. The results will be of practical significance in designing ridge waveguide components in microwave and millimeter wave engineering.     

Compression of a Parametric Array Signal in a Shallow-Water Waveguide

Acoustical Physics - The frequency dispersion of the sound propagation speed in a marine waveguide makes it possible to compress an acoustic signal with an increase in its intensity. The paper...     

Finite Element Analysis of the TE Modes in Truncated-Circular Waveguide

Truncated-circular waveguide are used in some microwave and millimeter-wave components. The field patterns in truncated-circular waveguide are desired but usually difficult to be computed by conventional methods. In this paper, they are efficiently determined by using finite element method. The electrical field lines of the dominant TE mode and the first sixteen higher-order TE modes are presented. The calculated results in this paper have important values for us to understand the transmission characteristics of truncated-circular waveguide, and will be of practical significance in designing waveguide components in microwave and millimeter wave engineering.     

Diffraction of a Guided Mode of a Dielectric Waveguide

Using the finite-difference time-domain method, we solve the problem of diffraction of a guided mode of a planar dielectric waveguide by an arbitrary-shaped body. Particular results are obtained for the scatterers in the form of isolated circular and elliptic cylinders and metal strips. We calculate the reflection and transmission coefficients of the mode along with the field structure in the near zone. Comparison with the results obtained by expansion in terms of plane waves is performed for a test problem of diffraction of the mode by a circular metal cylinder.     

金属覆盖介质波导在截止点附近的光学特性

本文提出一种适合于截止点附近计算含金属覆盖层介质波层的近似解析方法，详细；地讨论在截止点附近的光波导的模式传播特性 和光电调制特性，并结合有效折射率方法讨论了止型脊形波导调制器的截止条件。