Perturbation feedback method for analysing rectangular dielectric waveguides

A simple and accurate method for analysing rectangular dielectric waveguides is proposed. By virtue of a successive perturbation process, propagation constants and field distributions can be calculated with greater accuracy than other approximate approaches.<>     

Birefringence characteristics of benzocyclobutene rib optical waveguides

Zero-birefringence benzocyclobutene polymer rib waveguides as well as waveguides that exhibit low birefringence over a wide range of temperature are demonstrated. Experimental results agree well with theoretical calculations that take into account stress-induced birefringence.     

梯形截面介质光波导的模方程

本文简化了有效折射率法和WKB法对梯形截面介质光波导传输特性的分析过程,给出了计算E_(mn)~X模有效折射率的近似模方程,并用数值计算结果和实验结果检验了该模方程的精度。     

CMOS-compatible optical rib waveguides defined by local oxidation of silicon

The local oxidation of silicon process is shown to be an effective means of defining optical rib waveguides in silicon on insulator while maintaining the surface planarity required for CMOS integration. Experimental waveguides have shown singlemode operation and losses of less than 1 dB/cm in the telecommunications band around 1550 nm     

Silicon-on-insulator optical rib waveguide loss and modecharacteristics

Optical rib waveguides with rib heights of 3.17 and 7.67 microns with various widths have been formed in separation by implantation of oxygen (SIMOX) based silicon-on-insulator (SOI) structures. The effect of waveguide rib etch depth, width, and interface roughness on loss and mode characteristics have been studied at wavelengths of 1.15 and 1.523 microns. The experimental results support the hypothesis that certain rib dimensions can lead to single mode SOI waveguides even though planar SOI waveguides of similar multimicron dimension are not single mode. Mode loss was found to be strongly dependent on interface roughness and mode confinement     

SOI矩形光波导的有效折射率方法的研究

通过分析有效折射率方法在计算SOI矩形光波导中的误差,得出了从矩形波导的短边和长边分别计算波导的参数是不相同的结论,对于利用修正的有效折射率法求解波导参数有指导意义。     

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.     

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     

0.1 dB/cm waveguide losses in single-mode SOI rib waveguides

Waveguide losses as low as 0.1 dB/cm at a wavelength of /spl lambda/=1.3 /spl mu/m have been achieved in SOI rib waveguides fabricated by wet chemical etching. The single-mode waveguides have a large cross section yielding field mismatch losses to a standard single-mode fiber of only 0.17 dB/facet (both polarizations). Polarization independent fiber-chip-fiber insertion losses of 0.9 dB (best 0.5 dB) at a chip length of 60 mm have been measured.     

A rib optical waveguide with cutoff mesa isolation

A rib optical waveguide using the concept of optical cutoff to provide isolation between adjacent waveguides in a photonic integrated circuit is disclosed. Due to the evanescent nature of light propagation in cutoff waveguides, this cutoff mesa rib waveguide permits fabrication of single-moded rib waveguides with minimal self-interference and crosstalk by means of light guided in a remaining slab waveguide. Design rules are given and operation of a single-moded cut-off mesa rib waveguide and an MZI using this waveguide are demonstrated     

The single-mode condition for silicon-on-insulator optical rib waveguides with large cross section

Results from detailed numerical analyses of the modal characteristics of large-cross-section silicon-on-insulator-based rib waveguides are presented. They highlight for the first time that satisfying widely used design criteria is not sufficient to ensure single-mode behavior. In particular, the geometries that the design formulas predict should be single-mode are shown to support higher order vertical modes that do not couple (leak) into the outer slab region and are thus low loss in nature. Fortunately, a wide range of practical rib geometries still remains for which the leakage loss of modes other than those of EH/sub 00/ and HE/sub 00/ is sufficiently high to make the waveguides effectively single mode for each polarization.     

Simple method for estimating usable bend radii for deeply etched optical rib waveguides

An easy to use and extremely fast computational technique is presented for estimating the minimum usable radius of deeply etched, curved rib waveguides. This method is based on the effective index method and estimates the radius of curvature at which the bend becomes cut off due to substrate leakage.<>     

Single-mode condition for silicon rib waveguides

The geometrical conditions required for single-mode propagation in large cross-section silicon-on-insulator (SOI) waveguides were investigated using the beam propagation method (BPM). The cases of both vertical-walled and sloping-walled (trapezoidal) rib structures were considered. In the trapezoidal case some approximate methods were compared with the simulated results. Expressions for the single-mode condition for both types of waveguide were defined.     

Scattering losses in single and double heterostructure semiconductor optical rib waveguides

The relative scattering losses due to rough rib sidewalls in GaAs/AsGaAs single and double heterostructure rib waveguides are investigated theoretically. The authors find that double heterostructures exhibit at least as much scattering loss as single heterostructures, provided that such comparisons are made among structures with comparable bend performance.<>     

Effective index method for generalised waveguide dispersion characteristics analysis of optical channel waveguides

An approximate analysis of the generalised waveguide dispersion characteristics (GWDC) of optical channel waveguides based on the effective index (EI) method is presented. As an illustration of its practical applications, the possibility of achieving temperature-independence in glass rib waveguides is studied and predicted for the first time which may have important applications for integrated-optic devices requiring temperature-stabilised operations.<>     

Phase matched magneto optical single mode rib waveguides based on geometrical adjustments

In this work, we demonstrate via numerical simulation the design rules that must be imposed on the geometry of magneto optical rib waveguides to make them behave as single-mode and phase matched rib waveguides.     

Analysis of finite rib waveguides by matrix methods

The modal structure of finite lateral extent waveguides differs from that of the associated infinite structures by the presence of additional guided modes arising from the boundary conditions and by the discrete representation of the continuum modes. These differences are analyzed for a rib waveguide using matrix methods. The origin of the additional modes and their evolution with changing system parameters are discussed. The development of localized modes from delocalized modes is of particular interest, as is the evolution of radiation modes into discrete, localized modes of higher order as the rib increases in height. These developments are followed in detail and the changes in modal character are related to the properties of the finite system's dispersion curves. Illustrations of the effect of increasing system size on the localized and delocalized modes are given     

Sub-micrometer-thick and low-loss Ge20Sb15Se65 rib waveguides for nonlinear optical devices

The 885 nm direct pumping directly into the⁴F_3/2emitting level of Nd³⁺is applied on an Nd:Lu_0.15Y_0.85VO₄ crystal.The maximum output power of 2.8 W for continuous wave（CW）operation is obtained.For Q-switched operation,the maximum average output power is 1.2 W with pulse repetition of 23.69 kHz and pulse width of 35 ns at the pump power of 27.9 W.The high-quality fundamental transverse mode can be observed owing to the reduction of thermal effect for Nd:Lu_0.15Y_0.85VO₄ crystal by 885 nm direct pumping.     

Spectral index method for rib waveguide analysis

A new model for semiconductor rib waveguides is presented which provides fast and accurate solutions of the wave equation. The model has been implemented on a personal computer and produces values for the modal index (n/sub eff/) differing by less than 0.006% from those calculated using a sophisticated finite difference program.<>