Low-loss, single-mode, organic polymer waveguides utilizingrefractive index tailoring

Low-loss, single-mode optical waveguides have been fabricated from photopolymerizable acrylic monomers. The material system consists of a low-index cladding resin and a high-index core resin. The two resins are miscible so that precise control over the refractive index can be obtained. This allows the fabrication of single-mode waveguides with specific cross-sectional dimensions. One advantage of this is the ability to fabricate waveguides with high coupling efficiencies to other devices such as optical fiber or semiconductor lasers. The materials adhere to a wide variety of substrates and exhibit average waveguide losses of 0.56 dB/cm at 1300 nm for single-mode waveguides. Details of the fabrication procedure, index of refraction tailoring technique, and waveguide loss data are presented     

Full wave network representation for rectangular, circular, andelliptical to elliptical waveguide junctions

In this paper, two contributions to the study of the elliptical waveguides are given: an efficient technique to obtain the modal spectrum for elliptical waveguides and the analysis of the junctions between rectangular, circular, or elliptical to elliptical waveguides. In addition to theoretical results, experimental results are also presented finding good agreement between prediction and measurement     

The Method of Calculation of Open and Closed Waveguides,Which Is Based on the Modified Method of Discrete Sources

The problem of calculation of eigenmode characteristics is considered for 3D open dielectric waveguides and waveguides with the anisotropic impedance boundary condition. An efficient algorithm is proposed for finding eigenmodes of waveguides having different cross-sections. It is based on the solution of the auxiliary problem of diffraction of the field of a filamentous source located inside the waveguide. The method is tested using weakly directing dielectric waveguides having circular and elliptical sections and a waveguide with the two-sheeted section. The results of calculation of dielectric waveguides obtained with the help of the proposed method, the method of finite elements, and the method of the integral equation over the waveguide section are compared. The circular and elliptical waveguides and the waveguide having a two-sheeted section with an anisotropic impedance are also investigated. The calculation results are compared with the results obtained with the use of the method of separation of variables and the Galerkin method.     

Editorial, Jan. 1975

This Special Issue of the IEEE TRANSACTIONS on Microwave Theory and Techniques is devoted to two closely related fields: integrated optics and optical waveguides. The subject of optical waveguides is pertinent to optical communications by means of glass fibers and to the circuitry of integrated optics. The theory of optical waveguides has reached a stage of relative maturity while integrated optics is still in a relatively early stage of its development. Fiber waveguides seem to have a fairly secure future since the spectacular successes of glass fiber research almost certainly ensure their application in optical communications systems. Already there are examples of experimental military applications of optical fibers and their use in the telephone system is anticipated.     

Continuous spectrum, characteristic modes, and leaky waves of openwaveguides

The modes of open waveguides with nonseparable cross sections are derived by means of an extension of the resonance equation for the electromagnetic field. Such modes, forming a continuous spectrum, allow us to apply to discontinuity problems in open environments the techniques originally developed for closed waveguides. In this paper, the resonance equation is generalized according to functional analysis considerations. By this approach, it is possible to derive the modal spectrum from the simultaneous diagonalization of the real and imaginary parts of the admittance of the structure. A variational interpretation of the solution of the generalized resonance equation gives additional insight into the modes of open waveguides. The generalized resonance equation, when applied to three-dimensional objects, provides the well-known characteristic modes of these structures. The relationship between continuous spectrum, characteristic modes, and leaky waves is also discussed     

Single-mode, phosphorus-doped silica waveguides in siliconV-grooves

Single-mode, phosphorus-doped glass waveguides have been formed in silicon V-grooves by chemical vapor deposition. The fabrication process is reproducible, involves few steps, and produces waveguides with a loss on the order of 0.1 dB/cm at a wavelength of 0.633 μm. These waveguides are compatible with passive V-groove fiber alignment and out-of-plane coupling from integrated taps and end facets to surface-mounted optoelectronic devices     

A Design Procedure for High-Performance, Rib-Waveguide-Based Multimode Interference Couplers in Silicon-on-Insulator

Single mode silicon-on-insulator rib waveguides offer a weak lateral confinement, which makes it difficult to design high-performance multimode interference couplers (MMIs) based on these waveguides. Here, a complete design procedure for single etch step MMIs with tapered rib access waveguides is presented, which yields low excess loss (0.1 dB) and good imbalance (0.02 dB). Furthermore, polarization dependence is low, and high fabrication tolerances are achieved, especially with respect to etch depth.      

GaAs、GaP、InP、InGaAsP、AlGaAs、InAlGaAs的化学腐蚀研究

为研制全集成光开关、微片式激光器等，对ＧａＡｓ、ＧａＰ、ＩｎＧａＡｓＰ、ＩｎＡＩＧａＡｓ、ＡｌＧａＡｓ等材料的化学腐蚀进行了实验研究。为了研制ＩｎＡｌＧａＡｓ／ＩｎＡｌＡｓ／ＩｎＡｌＧａＡｓ微片式激光器，开发了Ｈ３ＰＯ４／Ｈ２Ｏ２／Ｈ２Ｏ薄层腐蚀液和ＨＣｌ／Ｈ２Ｏ选择性腐蚀液；为了研制ＩｎＧａＡｓＰ／ＩｎＰ／ＩｎＧａＡｓＰＴｂａｒ型光波导，开发了ＨＣｌ／Ｈ３ＰＯ４／Ｈ２Ｏ２薄层腐蚀液和ＨＣｌ／Ｈ２Ｏ２选择性腐蚀液；为了研制ＧａＰ、ＩｎＧａＰ光波导，开发了ＨＣｌ／ＨＮＯ３／Ｈ２Ｏ薄层腐蚀液。它们都具有稳定、重复性好、速率可控、腐蚀后表面形貌好等特点。除此之外，蚀刻成的ＧａＰ光波导侧壁平滑无波纹起伏。此种结果尚未见报导。     

Cut-off and phase constants of partially filled axially magnetized,gyromagnetic waveguides using finite elements

A three-component vector finite-element formulation for modeling the propagation characteristics of partially filled, axially magnetized, gyromagnetic waveguides is described. Covariant-projection elements have been used to avoid spurious modes, and periodic boundary conditions have been implemented to improve numerical efficiency. The classic quadratic functional derived from the vector, curlcurl, magnetic field equation is suited to evaluating the cut-off planes of gyrotropic waveguides. A known field transformation is used to reformulate the functional in a form convenient for calculating phase constants. Cut-off and phase constant solutions are presented for both fully and partially filled, longitudinally magnetized, ferrite-loaded waveguides     

Efficient modal analysis of arbitrarily shaped waveguides composed of linear, circular, and elliptical arcs using the BI-RME method

This paper deals with the accurate and efficient modal analysis of arbitrarily shaped waveguides whose cross section is defined by a combination of straight, circular, and/or elliptical arcs. A novel technique for considering the presence of circular and/or elliptical segments within the frame of the well-known boundary integral-resonant mode expansion (BI-RME) method is proposed. This new extended BI-RME method will allow a more accurate solution of a wider number of hollow conducting waveguides with arbitrary profiles, which are usually present in most modern passive waveguide components. To show the advantages of this new extended technique, the modal chart of canonical (circular and elliptical) waveguides, as well as of irises with great practical interest (i.e., cross-shaped irises with rounded corners) has been first successfully solved. Next, a computer-aided-design software package based on such a novel modal analysis tool has first been validated with the accurate analysis of a referenced complex dual-mode filter, and then applied to the complete design of a novel twist component for K-band application based on circular and elliptical waveguides. A prototype of this novel device has been manufactured and measured for verification purposes.     

Rigorous boundary integral equation solution for general isotropicand uniaxial anisotropic dielectric waveguides in multilayered mediaincluding losses, gain and leakage

Bounded and leaky eigenmodes of arbitrary shaped polygonal dielectric waveguides embedded in a multilayered medium are determined based on a rigorous full-wave analysis. The dielectric waveguides consist of isotropic or uniaxial anisotropic material. Losses and gain inside the layers and the waveguides are allowed. The eigenmodes are determined with a boundary integral equation technique in conjunction with the method of moments. Results for the propagation constants are presented for a number of waveguides and, where possible, compared with published data. Special attention is devoted to the transition from a dielectric waveguide to a perfectly conducting waveguide when the loss tangent of the waveguide material changes from zero to infinity     

Propagation and radiation characteristics of the circular electric,circular magnetic and hybrid waveguide modes

The field distributions and propagation constants of the circular electric, circular magnetic and hybrid modes of oversized waveguides are expressed, taking the effects of walls into account. These effects are described by wall functions which depend on surface impedances of the wall, and are determined for different types of guides. The near and far field patterns are derived in the case of real wall functions. It is shown that, for very oversized waveguides, the terms containing wall functions can be ignored in the calculations, and it results that the expressions of fields and propagation constants become independent of the types of waveguides. An application to corrugated waveguides for Electron Cyclotron Resonance Heating experiments shows the variations of the radiation characteristics versus geometric parameters of the corrugations and determines the ranges of interest for these parameters.     

太赫兹传输波导器件研究进展

随着太赫兹技术的发展,太赫兹传输波导器件的研究成为待解决的重要问题之一。太赫兹波位于微波与红外光之间,寻找高效的传输、耦合器件一直是研究人员的目标。主要介绍了太赫兹传输波导研究现状,并总结了各类型太赫兹波导的优势与不足。根据材料与结构分别对金属波导、介质波导的研究进展进行了分析。其中金属波导包括裸金属线波导、微结构波导、空芯波导以及平板波导,介质波导包括介质空芯波导、多孔芯波导以及微结构波导。最后分别对太赫兹传输波导未来需要解决的研究方向进行了展望。     

离散谱折射率法优化设计深刻蚀、单模GaAs/GaAlAs脊形光波导

采用离散谱折射率法对深刻蚀GaAs/GaAlAs多层脊形光波导的特性作了详细的理论分析,并对所获得的较大截面、低损耗的单模脊形光波导的制作容差性作了进一步的分析．计算表明,用离散谱折射率法获得的单模脊形光波导具有较大的制作容差性．     

Fabrication of low loss, waveguide grating filters using electronbeam lithography

A single step, electron beam writing process for the fabrication of low loss grating filters on AlGaAs rib waveguides is described. The technique allows both waveguide and grating to be defined in a single processing step. Linear loss measurements are presented which show that the presence of the grating has no significant effect on the throughput of the waveguides     

Time-delay measurement in singlemode, low-loss photonic crystal waveguides

The group delay in low-loss, singlemode, 1 mm-long photonic crystal slab waveguides is measured using the phase shift technique for the first time. Low group velocities (相似文献   

离散谱折射率法优化设计深刻蚀、单模GaAs/GaAlAs脊形光波导

采用离散谱折射率法对深刻蚀 Ga As/ Ga Al As多层脊形光波导的特性作了详细的理论分析 ,并对所获得的较大截面、低损耗的单模脊形光波导的制作容差性作了进一步的分析 .计算表明 ,用离散谱折射率法获得的单模脊形光波导具有较大的制作容差性 .     

Scattering by Material and Conducting Bodies Inside Waveguides, Part I: Theoretical Formulations

A general theoretical formulation of the problem of scattering by material and conducting bodies inside homogeneously filled waveguides is presented. It is based on a reformulation of the existing techniques for free-space scattering in order to adapt them for scattering inside waveguides. This gives rise to two basic alternatives. The first is the volume integral equation formulation (VIEF) and the second is the surface integral equation formulation (SIEF).     

Diffusion-limited etching for compact, low-loss semiconductor integrated optics

It is shown that diffusion-limited wet chemical etching can be used to fabricated single-mode GaAs/AlGaAs rib waveguides suitable for compact circular waveguide bends (300- mu m radius). The waveguides exhibit lower propagation losses (1-4 dB/cm at 1.52- mu m wavelength) than previously reported guides fabricated for compact bend applications by dry etching. To study the radius dependence of waveguide bend loss, a set of nested 90 degrees circular bends was fabricated simultaneously on a single chip.<>     

Observation of stimulated emission, line narrowing, and red shiftof emission peak from optically-pumped rectangular cross-sectional GaNoptical waveguides fabricated by selective growth

The authors examined low-loss III-V nitride optical waveguides for fabrication on sapphire substrates for active devices using a selective-area growth technique. A rectangular cross-section waveguide can be created by adjusting crystal growth conditions. A stimulated emission peak at 362 nm, line narrowing, and a red shift were observed from the selectively grown GaN waveguides by optical pumping