Design Of Optical Waveguide Devices Research Articles

Finite Element Beam Propagation Method Based on Coordinate Transformation for Optimal Design of Optical Waveguide Devices

Finite Element Beam Propagation Method Based on Coordinate Transformation for Optimal Design of Optical Waveguide Devices

Optimal Design of Optical Waveguide Devices Utilizing Beam Propagation Method with ADI Scheme

Optimal Design of Optical Waveguide Devices Utilizing Beam Propagation Method with ADI Scheme

Efficient topology optimization of optical waveguide using finite element method based on slowly varying envelope approximation

Abstract We propose a novel finite element method (FEM) for efficient optical waveguide analysis to improve the computational efficiency in inverse design of optical waveguide devices. In our formulation, applying slowly varying envelope approximation (SVEA) to FEM, an electromagnetic field expression is split into a slowly varying complex envelope amplitude and a steady-state oscillating term. Then, field profile can be obtained by just solving the slowly varying complex envelope amplitude and the number of unknown variables along the propagation direction can be greatly reduced. The proposed method can achieve efficient optical waveguide analysis. Furthermore, by employing this analysis method in the inverse design of optical waveguide devices, automatic optimization of device structure can be carried out with reasonable computational costs.

Function-expansion-based topology optimization of three-dimensional optical waveguide devices with multi-layered structure considering layer thickness

So far, as an optimal design method for 2D and 3D design of optical waveguide devices, topology optimization based on a function expansion method has been reported. In this paper, we improve the conventional function-expansion-based topology optimization method to design three-dimensional photonic devices with structural variation in the depth direction. In order to design realistic 3D optical waveguide devices, we consider a layered structure and design each layer by using function-expansion-based topology optimization method. In this approach, undesired floating structures are avoided and layer thickness can be optimized. The validity of this method is verified through design examples of a polarization splitter and rotator (PSR) and a crossing waveguide which have two-layer structure.

Shortcuts to adiabaticity in optical waveguides using fast quasiadiabatic dynamics.

We propose a fast quasiadiabatic approach to the design of optical waveguide devices. This approach distributes the system adiabaticity homogeneously over the device length, thus providing a shortcut to adiabaticity at a shorter device length. A mode sorting asymmetric Y junction is designed by redistributing the adiabaticity of a conventional linearly separating Y junction. Simple procedures for the design of fast quasiadiabatic devices are outlined, and the designed Y junction features large bandwidth at a shorter length than the conventional linearly separating Y junction. The proposed device is verified with beam propagation simulations. A mode conversion efficiency of larger than 99% is observed for the designed Y junction over a 220 nm range.

Study of optical anisotropies in benzocyclobutene thin films for the efficient design of optical waveguide devices

We study the in-plane/out-of-plane anisotropies in refractive indices (n) and in thermo-optic coefficients (dn/dT) of benzocyclobutene (BCB) thin film on a substrate. Both nonoxidized and oxidized films are investigated. Aside from the stress-induced effects, oxidation has significant influence on the refractive index anisotropy. The dependence of the anisotropy on each of the thermal stress and the oxidation is determined quantitatively. The anisotropies in the dn/dT values are mainly caused by the thermal stress and are independent of oxidation. However, the original (stress-free) thermo-optic coefficients are obtained as isotropic and significantly different than the measured dn/dT values. Our findings have the potential to optimize the design of polarization insensitive and/or athermal BCB optical waveguide devices.

Beam propagation method based on finite element scheme and its application to optical waveguide analysis

AbstractIn regard to the beam propagation method (BPM), one of the indispensable analysis tools for the design of optical waveguide devices and optical circuits, this paper treats the FE‐BPM based on the finite element method, which allows an efficient analysis using adaptive meshes and provides basic concepts. The paper also refers to the time‐domain BPM, which can automatically take care of the reflected wave, and to the imaginary‐distance BPM, which can easily carry out eigenmode analysis including leaky modes. In addition to examples of generated adaptive meshes, analysis examples of photonic crystal circuits and three‐dimensional ARROW waveguides are presented so that the effectiveness and usefulness of the FE‐BPM are demonstrated. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 85(10): 29–39, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.1112

Study of polarization-dependent coupling in optical waveguide directional couplers by the effective-index method with built-in perturbation correction

Polarization dependence is a major factor of consideration in the design of optical waveguide devices for application in optical fiber transmission systems. In this paper, we apply the recently proposed effective-index method with built-in perturbation correction to the study of the polarization dependence in the coupling coefficient of a directional coupler that consists of two parallel rectangular-core waveguides. Numerical results are found to agree with those calculated by the vector version of the Marcatili method with perturbation correction. With numerical illustrations, we show that the polarization dependence in the splitting ratio of a directional coupler can be eliminated by a proper choice of the physical parameters of the coupler. Our results provide useful guidelines for the design of polarization-insensitive integrated-optic directional couplers.