Mol numerical analysis of nonlinear planar waveguide

In this paper the method of lines is applied to simulate the electromagnetic field propagation in an optical dielectric nonlinear planar waveguide, with saturation of the refractive index. A comparison of the solutions obtained with the method of lines and the beam propagation method (which uses paraxial approximation) is performed     

平面光波导膜层厚度对传播损耗的影响

根据平面光波导损耗的波动理论，通过分析计算，对于传播损耗随波膜厚度的变化关系提出了新的看法，文中给出了一组以波导膜厚度为参变量的传播损耗曲线，说明在某些波导膜厚度范围内，不能有效地进行光波导传播。     

Pulse propagation in a nonlinear dielectric slab waveguide

The evolution of an optical pulse in a single-mode, step index dielectric slab waveguide which is characterized by an intensity dependent dielectric function in the core and cladding regions is treated by means of differential equation techniques. A cubic order non-linearity is considered. The electromagnetic field distribution in the slab waveguide region satisfies a non-linear wave equation. This field can be represented in terms of even TE guided modes with a slowly varying envelope amplitude function. Then using the well known approximation, based on the slowly varying character of the amplitude function, a non linear partial differential equation is obtained for the amplitude function. As the coefficients of this equation depend on the distance across the transverse direction X, an averaging technique over x is applied to reduce the nonlinear partial differential equation into a form that is easily transformed to the so-called non-linear Scroedinger differential equation. This equation is then attacked by means of the well known Inverse Scattering method in the case of reflection less potentials. The single and double soliton solutions are obtained explicitly for a single-mode slab waveguide. Finally numerical results are presented in the time domain.     

On the propagation of light waves in a multilayer planar dielectric waveguide

Dispersion equations for the eigenvalues of effective refractive index β of a planar dielectric waveguide supporting an optic TE wave are investigated. A relation between the traditional dispersion equation obtained on the basis of the characteristic-matrix method and the so-called multilayer equation is revealed. It is shown that all of the roots of the traditional dispersion equation are roots of the multilayer equation for the same problem. It is found that the roots of the multilayer equation may include the values of the refractive indices of inner layers of the waveguide and that these values are not the eigenvalues of quantity β.     

Phase-plane approach to nonlinear propagation in dielectric slabwaveguide

Nonlinear propagation in dielectric slab waveguides is discussed in the framework of a phase-plane approach. It is shown that qualitative aspects, such as integrals of motion in phase-plane, emerge from the analysis. Systematic consideration of these quantities narrows the range of possible solutions and provides a direct physical interpretation of them. Particularly suggestive, in this respect, are the interpretations of the appearance of higher order modes and of the energy/boundary conditions constraints typical of the nonlinear problem. Results for the TE and TM cases are presented     

A matrix formulation for large scale numerical computation of the finite planar waveguide array problem

In the present work, the finite planar waveguide array problem is formulated as a matrix equation. It is shown that entries of the matrix are independent of the scan angles, and it is necessary to compute and invert the matrix only once in order to obtain information on the array Scanning operation at any angular position. It is also shown that the use of certain symmetry relations greatly reduces the computation time of the matrix entries. Finally, a numerical example is given to demonstrate the effectiveness of the matrix formulation in treating the finite array problem.     

平板宽波导谐振腔耦合损失理论研究

计算了平板宽波导谐振腔中ＥＨ１１模的耦合损失，结果表明存在两种特定结构使耦合损失最小。     

平面左手结构色散与传播特性分析

采用时域有限差分方法研究了一种新型平面结构阵列在左手频带内的后向波传播特性与负折射特性,提出分析二维平面左手结构的新方法:基于单元结构的四端口网络参数进行Bloch分析,得出色散关系和Bloch阻抗;根据色散关系和Bloch阻抗分析相位与能量传播方向的关系,以确定出左右手特性频带.相比于以往单元结构分析方法,本文方法利于单元结构的灵活设计,能较好地考虑分布参数元件色散特性,能简便准确地判断出左右手特性频带,且能用于分析各向异性和有损耗结构.仿真分析结果验证了方法的有效性.     

A 12 GHz-band planar waveguide array antenna for compact rangeapplication-a preliminary study

For the purpose of generating a quasi-plane wave and realizing small-antenna pattern measurements in the 12 GHz band, a planar-waveguide array antenna consisting of 45 WRJ-120 rectangular waveguides with 57 longitudinal slots on the broad wall of each waveguide is fabricated and tested. The dimensions of the antenna are about 1100 mm×1300 mm×850 mm, including the waveguide-supporting frame, the feed network, and the antenna-supporting pedestal. As an example, the H-plane pattern measurement of a small pyramidal horn antenna is conducted in a small chamber at 12 GHz. The pattern obtained in the compact range is compared with the corresponding data obtained outdoors     

Numerical analysis of planar optical waveguides using matrix approach

We present here a simple matrix method for obtaining propagation characteristics, including losses for various modes of an arbitrarily graded planar waveguide structure which may have media of complex refractive indices. We show the applicability of the method for obtaining leakage losses and absorption losses, as well as for calculating beat length in directional couplers. The method involves straightforward 2 × 2 matrix multiplications, and does not require the solutions of any transcendental or differential equations.     

New simple procedure for the computation of the multimodeadmittance or impedance matrix of planar waveguide junctions

Much effort has been devoted in the past to the development of electromagnetic simulation algorithms for waveguide junctions that could at the same time include higher-order mode interactions and lead to computationally efficient codes. Even though this is indeed a classical subject, there is still a strong interest in this area as waveguide systems become increasingly complex, and ever shorter development and manufacturing times are required. In this paper a simple method is described for the evaluation of the multimode network representation of planar waveguide junctions in terms of admittance or impedance parameters. The key feature of the method is that it starts from the wanted final results, the equivalent network representation, in order to obtain an analytic expression for the evaluation of the relevant matrix elements. The procedure is based on general network theory and is equivalent to ideally measuring directly the value of the admittance or impedance elements. In this paper the evaluation procedure is fully described. Measured results of actual hardware are then compared with simulations indicating that the codes developed are indeed very accurate as well as computationally very efficient     

Calculation of approximate propagation characteristics for any given two-dimensional optical waveguide

An approximation technique of determining propagation characteristics of a given cross-section graded-index optical waveguide is presented. The numerical technique gives very short computational times and is easy to use.     

A planar probe double ladder waveguide power divider

The successful demonstration of a 1:4 power divider using microstrip probes and a WR-430 rectangular waveguide is presented. The 15-dB return loss bandwidth of the nonoptimized structure is demonstrated to be 22% and its 0.5-dB insertion loss bandwidth 26%. While realized through conventional machining, such a structure is assembled in a fashion consistent with proven millimeter and submillimeter-wave micromachining techniques. Thus, the structure presents a potential power dividing and power combining architecture, which through micromachining, may be used for applications well above 100GHz.     

Wavelength dependent propagation loss characteristics of SiGe/Si planar waveguides

The propagation loss of Si/sub 0.9/Ge/sub 0.1//Si planar optical waveguides has been measured at wavelengths of 1.15 and 1.523 mu m. The results show that these waveguides have a low propagation loss (<1 dB/cm) at a wavelength of 1.523 mu m, which is due to the intrinsic absorption of SiGe whereas at a wavelength of 1.15 mu m its loss is determined by both the SiGe absorption edge and defects at the SiGe/Si interface.<>     

SOI光波导传输机理及其损耗的研究

分析研究了ＳＯＩ光波导传输机理,并对其传输损耗进行了计算。     

Liquid crystal planar waveguide beam shifters: a comparative study

In this paper, we propose a technical alternative to the implementation of analog multistage switches that use optical beam shifters, in which 2-inputs adjacent ports are interconnected to 2-ouputs. The principle is based on the refraction of the extraordinary beam, in a planar liquid crystal waveguide, whose anisotropy can be electrically modified. We present here preliminary results and discuss the advantages and limitations of such a solution with respect to the conventional freespace switch based on the use of liquid crystal polarization controllers. In particular, we show that this solution can present some interesting advantages with respect to telecommunication system specifications, such as crosstalk, insertion losses and bandwidth range. Finally, we discuss possible technical improvements and intrinsic limitations.     

Self-trapped propagation in the nonlinear cubic-quintic Schrodingerequation: a variational approach

In the framework of a variational approach, we determine approximate analytical expressions for the self-trapped solutions in the cubic-quintic nonlinear Schrodinger equation (NLCQSE) and compare our solutions with the available exact ones. Through our approach, we also discuss the stability of the solutions and give simple explanations to the physical meaning of the bistable soliton regime, which can be obtained for some parameter values     

激光泵浦平板染料波导的“被导”和“自导”特性

本文实验观测了N_2激光泵浦平板染料波导的各种“被导”和“自导”特性,双程染料池在x方向是“被导”的;在y方向是“自导”的。     

Modes of a planar nonlinear-metamaterial waveguide

Modes of a planar dielectric waveguide are investigated. The waveguide is made from a nonlinear metamaterial with a negative permittivity and a negative permeability. The mode wavenumbers and field distributions are calculated for structures with parabolic permittivity and permeability profiles. It is shown that anomalously high field intensities can be observed in such a structure. The dependences of the mode propagation coefficients on the electric field are analyzed for the case of nonlinear media. The effect of nonlinearity saturation is considered.     

平面光波导器件的发展

在光电子技术,计算机技术,通信技术迅速发展的今天,光波导材料和器件得到了越来越多的应用和发展.因此,对于光波导器件现状及发展趋势的叙述,不但对有志于在此方面研究的人具有一定参考价值,同时也是面向未来光电子产业发展的必然要求.因为当今大多器件应用平面光波导材料,所以主要对平面光波导理论进行了讨论.