Wave Optics Module

Wave Optics Module

For Simulating Electromagnetic Wave Propagation in Optically Large Structures


OPTICAL DEVICES: In this example of an optical waveguide, a wave propagates around a ring and interferes with a wave propagating in a straight waveguide. The Field Continuity boundary condition is used to make the field continuous on a boundary with a discontinuous phase.

Image made using the COMSOL Multiphysics® software and is provided courtesy of COMSOL.

Wave Optics Module


Software for Simulating Optical Design Components

The Wave Optics Module provides dedicated tools for electromagnetic wave propagation in linear and nonlinear optical media for accurate component simulation and optical design optimization. With this module you can model high-frequency electromagnetic wave simulations in either frequency- or time-domain in optical structures. It also adds to your modeling of optical media by supporting inhomogeneous and fully anisotropic materials, and optical media with gains or losses. Several 2D and 3D formulations are available in the Wave Optics Module for eigenfrequency mode analysis, frequency-domain, and time-domain electromagnetic simulation. You can calculate, visualize, and analyze your phenomena using postprocessing tools, such as computation of transmission and reflection coefficients.

Analysis for All Types of Optical Media

It is straightforward to simulate optical sensors, metamaterials, optical fibers, bidirectional couplers, plasmonic devices, nonlinear optical processes in photonics, and laser beam propagation. This can be done in 2D, 2D axisymmetric, and 3D spatial domains. Ports can be defined for inputs and outputs, as well as for automatic extraction of S-parameters matrices that contain the full transmission and reflection properties of an optical structure with, potentially, multiple ports. A variety of different boundary conditions can be applied to simulate scattering, periodic, and discontinuity boundary conditions. Perfectly-matched layers (PMLs) are ideal for simulating electromagnetic wave propagation into unbounded, free space while keeping computational costs down. The postprocessing capabilities allow for visualization, evaluation, and integration of just about any conceivable quantity, since you can freely compose mathematical expressions of fields and derived quantities.


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Product Features

  • In-plane, axisymmetric, and full-wave 3D electromagnetic wave propagation
  • Specialized beam envelope method for efficient simulation of large structures
  • User-defined materials that can be graded index, frequency-dependent, anisotropic, and lossy
  • Negative-index and metamaterials
  • Multiphysics enabled optics analysis coupled to heat transfer, structural analysis, and fluid flow
  • Frequency-domain, time-domain, and eigenmode analyses
  • Periodic structures with higher-order Floquet modes
  • Perfectly matched layers (PMLs) for optimal representation of infinite domains
  • Scattered field formulation for planar, cylindrical, spherical, Gaussian, or user-defined incident fields
  • Transmission and reflection through scattering parameters (S-parameters)
  • Advanced visualization capabilities for arbitrary field quantities
  • Drude-Lorentz, Debye, and Selmeier dispersion models

Application Areas

  • Photonic devices
  • Integrated optics
  • Waveguides
  • Couplers
  • Fiber optics
  • Photonic crystals
  • Fiber Bragg gratings
  • Nonlinear optics
  • Harmonic generation with frequency mixing
  • Optical scattering
  • Surface scattering
  • Scattering from nanoparticles
  • Lasers and amplifiers
  • Semiconductor lasers
  • Rod, slab, and disk laser design
  • Laser heating
  • Optoelectronics
  • Optical lithography
  • Optical sensors

Models

This model demonstrates the polarization properties for a Gaussian beam incident at an interface between two media at the Brewster angle.

The model shows how to use the Electromagnetic Waves, Beam Envelopes physics interface with a User defined phase specification. Matched Boundary Condition features are used for absorbing waves incident to boundaries at non-normal directions.

» See model.

This model demonstrates the simulation of the scattering of a plane wave of light by a gold nanosphere. The scattering is computed for the optical frequency range over which gold can be modeled as a material with negative complex-valued permittivity. The far-field pattern and losses are computed.

» See model.

Two embedded optical waveguides in close proximity form a directional coupler. The cladding material is GaAs and the core material is ion-implanted GaAs. The waveguide is excited by the two first supermodes of the waveguide structure – the symmetric and antisymmetric modes. Two numeric ports are used on both the exciting boundary and the absorbing boundary, to define the two modes. A boundary mode analysis study sequence is set up, with four boundary mode analyses and a final frequency-domain study. The model demonstrates coupling from one of the waveguides to the other waveguide.

» See model.

Polarizing beam splitter cubes consist of two right-angled prisms where a dielectric coating is applied to the intermediate surface. The cube transmits part of the incident wave while reflecting the other part. An advantage of using this cube design, instead of a plate design, for beam splitters is that ghost images are avoided.

This new app demonstrates the basic MacNeille design, which consists of pairs of layers with alternating high and low refractive indices, and where you can select how many layers will make up your splitter. You can enter refractive indices for the prisms and the layers in the dielectric stack, either directly or through a predefined material list.

Sweeps can be performed over a range of wavelengths or spot radii. The app displays the norm of the total electric field and the electric field for the first and second wave for a given wavelength or spot radius and polarization. Also presented is the reflectance and transmittance.

» See model.

A plane wave is incident on a reflecting hexagonal grating. The grating cell consists of a protruding semisphere. The scattering coefficients for the different diffraction orders are calculated for a few different wavelengths.

» See model.

Surface plasmon-based circuits are being used in applications such as plasmonic chips, light generation, and nanolithography. The Plasmonic Wire Grating Analyzer application computes the coefficients of refraction, specular reflection, and first-order diffraction as functions of the angle of incidence for a plasmonic wire grating on a dielectric substrate.

The model describes a unit cell of the grating, where Floquet boundary conditions define the periodicity. Postprocessing functionality allows you to expand the number of unit cells and extract the visualization into the third dimension.

Built into the app is the ability to sweep the incident angle of a plane wave from the normal angle to the grazing angle on the grating structure. The app also allows you to vary the radius of a wire as well as the periodicity or size of the unit cell. Further parameters that can be varied are the wavelength and orientation of the polarization.

The application presents results for the electric field norm for multiple grating periodicity for selected angles of incidence, the incident wave vector and wave vectors for all reflected and transmitted modes, and the reflectance and transmittance.

» See model.

This is an example of a Fabry-Perot cavity, the simplest optical resonator structure. It is a classical problem in optics and photonics. Two methods are shown for computing the Q-factor. The losses in this model are purely via radiation away from the resonator.

» See model.

A Mach-Zehnder modulator is used for controlling the amplitude of an optical wave. The input waveguide is split up into two waveguide interferometer arms. If a voltage is applied across one of the arms, a phase shift is induced for the wave passing through that arm. When the two arms are recombined, the phase difference between the two waves is converted to an amplitude modulation.

This is a multiphysics model, showing how to combine the Electromagnetic Waves, Beam Envelopes interface with the Electrostatics interface to describe a realistic waveguide device.

» See model.

Photonic crystal devices are periodic structures of alternating layers of materials with different refractive indices. Waveguides that are confined inside of a photonic crystal can have very sharp low-loss bends, which may enable an increase in integration density of several orders of magnitude. This is a study of a photonic crystal waveguide. The crystal features a grid of GaAs pillars. Depending on the distance between the pillars, waves within a certain frequency range will be reflected instead of propagating through the crystal. This frequency range is called the photonic band gap. When some of the GaAs pillars in the crystal structure are removed, a guide for the frequencies within the band gap is created. Light can then propagate along the outlined guide geometry.

» See model.

The transmission speed of optical waveguides is superior to microwave waveguides because optical devices have a much higher operating frequency than microwaves, enabling a far higher bandwidth. Single-mode step-index fibers are used for long-haul (even transoceanic) communication, whereas both graded-index and step-index multimode fibers are used for short-distance communication, for example, within institutions and university campuses and buildings.

For almost all commercial optical fiber types, the design consists of a concentric layer structure with the inner layer(s) forming the core and the outer layer(s) forming the cladding. Since the core has a higher refractive index than the cladding, guided modes can propagate along the fiber.

The Optical Fiber Simulator app performs mode analyses on concentric circular dielectric layer structures. Each layer is described by an outer diameter and the real and imaginary parts of the refractive index. The app can be used for analyzing both step-index fibers and graded-index fibers. These fibers may have an arbitrary number of concentric circular layers.

» See model.