1.5-/spl mu/m InGaAsP-InP slab-coupled optical waveguide lasers

We report the demonstration of high-power semiconductor slab-coupled optical waveguide lasers (SCOWLs) operating at a wavelength of 1.5 /spl mu/m. The lasers operate with large (4/spl times/8 /spl mu/m diameter) fundamental mode and produce output power in excess of 800 mW. These structures have very low loss (/spl sim/0.5 cm/sup -1/) enabling centimeter-long devices for efficient heat removal. The large fundamental mode allows 55% butt-coupling efficiency to standard optical fiber (SMF-28). Comparisons are made between SCOWL structures having nominal 4- and 5-/spl mu/m-thick waveguides.     

Modal analysis of strip-loaded diffused optical waveguides by a variational method

The propagating modes supported by strip-loaded three-dimensional diffused optical waveguides are analyzed in detail theoretically by using a variational method. Some typical numerical examples of the propagation constants and the field distributions are illustrated. The dependence of propagation characteristics on the geometrical parameters of the loading dielectric strip is discussed.     

Calculation of the fundamental mode sizes in optical channelwaveguides using Gaussian quadrature

A fast numerical method using Gaussian quadrature, which takes only seconds on a microcomputer, is presented for calculating the fundamental mode sizes in optical channel waveguides. Variational expressions for the square of the propagation constant, β² , of the TE- and TM-like modes are derived using the vector wave equations. For channel waveguides with gradual refractive index distributions, these expressions approach the variational expression obtained using the scalar wave equation. To show the usefulness of the numerical technique the authors present the results for titanium indiffused lithium niobate channel waveguide which are commonly used in integrated optical circuits. Since these waveguides have gradual refractive index distributions, both types of expressions give the same results; however, it takes less time to compute the mode sizes when using the variational expression obtained from the scalar wave equation. The authors find the calculated mode sizes are in good agreement with published measurements. From the comparison process, best fit parameters are obtained, which give mode sizes close to the values published in the literature. For one special case the authors are able to obtain an analytical variational expression and they use it to test the accuracy of the numerical method. They find that the values of β² given by both methods agree to six significant figures     

A simple and accurate model analysis of strip-loaded opticalwaveguides with various index profiles

A simple first-order perturbation approach has been developed to study the propagation characteristics of strip-loaded diffused waveguides with various refractive index profiles. Propagation constants of the guided modes of rib waveguides and strip-loaded waveguides with exponential and Gaussian refractive index profiles are obtained. The results are in good agreement with those reported in the literature that were obtained by variational and numerical techniques. The presented technique provides analytical expressions for the modal field profile that should be useful in the design of various integrated optical devices     

Cu离子交换过程对制备玻璃平面光波导特性的影响

用Cu离子交换技术,制备了soda-lime玻璃平面光波导。通过棱镜耦合技术测量了波导的有效折射率,用反WKB方法拟合得到了平面波导的折射率分布。研究发现,离子交换时间和温度2个可控的制备参数对制备的玻璃平面波导特性有较大影响,随着离子交换时间和温度的增加,波导的模式数和波导深度并非随之单调增加,波导模式数随着离子交换时间的增加先增加而后减小,而适当的离子交换时间可以使制备的波导具有最大的模式数和波导深度,且在该条件下增加离子交换温度可以提高Cu离子交换波导的蓝-绿发光强度,宽带发光中心波长在520 nm附近,发光强度取决于样品中Cu+的浓度以及Cu2+的影响。     

Design for Y-branch waveguides with wide angle and low loss

A novel method to design Y-branch waveguides is proposed by using total internal reflection, and the optical properties areanalyzed. The simulated results show that the optical loss values of two Y-branch waveguides with the branching angles of 12° and 30° are only 0.310 dB and 0.645 dB, respectively. Compared with conventional Y-branch waveguides, the opticalperformance of the proposed ones is well improved, which has many advantages such as wide angle, low loss, simplestructure and easy for fabrication.     

Analytical expressions of the guided mode field distribution:analysis and comparison

Methods for determining the parameters of the three different approximate solutions for the fundamental mode field distribution of Ti:LiNbO₃ optical waveguides by using the variational technique are presented. This analysis gives closer approximation not only to the field distribution, but also to the propagation constant. Comparison with the exact results for the exponential index distribution in depth shows that these trial functions are closer to the real solution. It is also shown that these solutions are as accurate as the effective index method for Ti:LiNbO₃ strip waveguides. The analysis provides an approach for comparing and assessing these solutions     

A simple variational approach to optical rib waveguides

A simple method for the calculation of the mode properties of optical rib waveguides is presented. The method is based on a scalar variational principle combined with a vector perturbation analysis for the polarization correction. It is demonstrated that, with the proper trial functions, the approach can predict very accurately the dispersion characteristics with much less effort (in terms of formulation and computation) than the existing numerical techniques. The field patterns of the modes can be computed from the scalar analysis. The vector property of the mode can be taken into account by a perturbation formula. The computation is carried out on an IBM PC. The user-friendly computer program is written in Fortran     

Guided modes of nonlinear slot waveguides

Guided modes of nonlinear slot waveguides are investigated for the first time and their unusual modal properties are demonstrated. Nonlinear phase shifts of slot waveguides induced by optical Kerr effect exhibit saturable behavior for strong optical intensity. This is because a self-localization effect of electromagnetic fields induced by optical Kerr effect is compensated with a field broadening originating from a unique confinement mechanism of slot waveguides. Nonlinear phase shifts on various structural parameters are thoroughly investigated. All the results presented in this letter are obtained by using a rigorous full-vector finite-element method to ensure accurate analysis.     

Scalar Variational Analysis of Single-Mode Waveguides with Rectangular Cross Section (Short Papers)

We use the variational method to analyze single-mode optical waveguides with rectangular cross section. In particular, we propose a new trial field and show that it gives much better results and involves less computational effort as compared to other trial functions.     

用于现代雷达系统的光波导

介绍了用于现代雷达系统的光波导的基本特性和设计考虑，包括其物理和传输性能。简介光波导的种类，讨论几种常用的光耦合技术和波导材料。指出光波导在现代雷达系统中应用的未来发展方向。     

用Tl_2SO_4制造玻璃光波导

本文报道了用TI盐(TI_2SO_4)离子交换法制备玻璃光波导的实验结果。与用AgNO_3离子交换制备的光波导相比,波导损耗较低,折射率分布呈准阶跃型,拟合确定其折射率分布函数为费米函数,折射率增量Δn>0.13。     

P(VDF/TrFE)聚合物薄膜光波导的实验研究

采用棱镜耦合法和偏振反射技术研究了Ｐ（ＶＤＦ／ＴｒＦＥ）聚合物薄膜光波导特性。配制适当重量比浓度的Ｐ（ＶＤＦ／ＴｒＦＥ）溶液,通过提高极化时的温度,可制成均匀透明的极化聚合物薄膜平面波导。Ｐ（ＶＤＦ／ＴｒＦＥ）成膜后薄膜内部的晶界与晶粒对于其光学性质的影响可以获得较大改善。样品用旋涂法制备。研究了制备工艺对光学特性的影响。     

A scalar variational analysis of rectangular dielectric waveguidesusing Hermite-Gaussian modal approximations

A scalar variational analysis of rectangular dielectric waveguides using Hermite-Gaussian modal approximations is presented. The technique analyzes waveguides by finding a closed-form, approximate solution to the given problem. We begin with an assumed, closed-form field solution, with unknown parameters which can be chosen to best match the assumed field to the actual field solution using variational principles. The values of the unknown parameters of the assumed field are determined by solving a set of simultaneous equations, not by a search method. As a result, this analysis method is computationally fast. Another benefit is that this method gives best-fit, closed-form modal approximations     

Numerical analysis of nonlinear bistable optical waveguides

Numerical solutions illustrating the onset of bistability and hysteresis are presented for the symmetrical step index, asymmetrical step index, and asymmetrical diffused slab nonlinear optical waveguides. Two different numerical techniques have been used independently-a finite-element method and a variational method. Both methods produce numerically stable solutions, and agreement between them is good for both increasing and decreasing total power from below or above the threshold power. The results are compared with analytical solutions for these structures. The onset and the end of the physically unstable solutions regime coincides with the two power thresholds for the increasing and decreasing powers     

Mode dispersion of trapezoidal cross-section dielectric optical waveguides by the effective-index method

The mode dispersion of dielectric optical waveguides is calculated by the effective-index method and is compared with previously reported experimental and theoretical finite-element results for trapezoidal cross-section waveguides. Agreement between experimental and predicted results is very good. This is significant because it means that stripe waveguides can be designed with specific modal propagation properties using the much simpler effective-index method even though the waveguide cross-section is not rectangular.     

Phase constants and scattering electromagnetic properties of circular dielectric waveguides

A variational method, based on the telegraphist's equations, is used to calculate the dispersion and scattering characteristics of circular dielectric waveguides which arc enclosed by perfectly conducting walls of rectangular cross-section. Our propagation solutions are compared with those obtained by other authors and the convergence of the method is evaluated. A procedure which combines this variational method with the modal matching technique was implemented in order to analyse multiple discontinuities in cyclindrical dielectric waveguides. To verify the usefulness and accuracy of the procedure, theoretical and experimental results were obtained for different dielectric guiding structures, connected by means of abrupt and gradual transitions. The experimental values show a good agreement with the theoretical ones.     

光纤中光学高斯型脉冲的传输特性研究

应用变分法，研究了微扰对光学高斯型脉冲在光纤中非线性传输特性的影响，导出了光学高斯型脉冲参数演化的动力学方程。     

新的质子源质子交换制作的Z切LiNbO3光波导特性

研究了用己二酸和苯甲酸的不同混合摩尔比作为质子源交换制作的Z切LiNbO3光波导的表面折射率改变、波导深度、折射率分布等光学特性。结果表明，在交换温度为230℃，交换时间为6h时，混合摩尔比较高时，波导为β4相；较低时，为β3相。在β4相时，混合摩尔比越大，波导的表面折射率改变和波导的深度越大；在β3相时，不同的混合摩尔比交换的波导光学特性差别不明显。用双晶X射线衍射法对单苯甲酸和混合摩尔比为60％制作的光波导进行X射线衍射。以上结果对波导器件的制作及理解波导折射率改变的物理机制提供了一些有用的信息。     

弯曲光波导端面修饰的设计方法

光波导的弯曲损耗一直是集成光学中一个值得人们重视的问题,为有效地减小光波导弯曲损耗,弯曲光波导的设计成为集成光学波导设计中的一个重要内容.本文在弯曲光波导保形变换方法的基础上,应用几何光学分析方法给出了波导弯曲损耗产生的简洁的物理图像,从而深入地分析了弯曲损耗产生的根本原因,并由此提出了弯曲光波导端面修饰的设计方法.理论分析表明,与传统的弯曲的光波导设计相比,该种设计方法可以有效地减小导波的模式泄漏,从而减小波导弯曲损耗.尤其是在弯曲光波导曲率半径、材料折射率等参数被设定的情况下,该种设计方法成为一种有效的设计方法.