The Application Gallery features COMSOL Multiphysics® tutorial and demo app files pertinent to the electrical, structural, acoustics, fluid, heat, and chemical disciplines. You can use these examples as a starting point for your own simulation work by downloading the tutorial model or demo app file and its accompanying instructions.

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Directional Coupler

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 ...

Nanorods

A Gaussian electromagnetic wave is incident on a dense array of very thin wires (or rods). The distance between the rods and, thus, the rod diameter is much smaller than the wavelength. Under these circumstances, the rod array does not function as a diffraction grating (see the Plasmonic Wire Grating model). Instead, the rod array behaves as if it was a continuous metal sheet for light polarized ...

Gaussian Beam Incident at the Brewster Angle

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.

Stress-Optical Effects with Generalized Plane Strain

Planar photonic waveguides in silica (SiO2) have great potential for use in wavelength routing applications. The major problem with this type of waveguide is birefringence. Anisotropic refractive indices result in fundamental mode splitting and pulse broadening. The goal is to minimize birefringence effects by adapting materials and manufacturing processes. One source of birefringence is the use ...

Self-Focusing

A Gaussian beam is launched into BK-7 optical glass. The material has an intensity-dependent refractive index. At the center of the beam, the refractive index is the largest. The induced refractive index profile counteracts diffraction and actually focuses the beam. Self-focusing is important in the design of high-power laser systems. The model demonstrates 3D nonlinear wave propagation.

Step-Index Fiber Bend

The first part of the application computes the modes for a straight step index fiber made of silica glass. In the second part, a step index fiber bend with a 3 mm radius of curvature is analyzed with respect to propagating modes and radiation loss. It is shown how to find the power averaged mode radius and how to use this to compute the effective mode index.

Second Harmonic Generation of a Gaussian Beam (Wave Optics)

It is possible to generate harmonics that are multiples of the frequency of laser light by using nonlinear optical materials. This model demonstrates second harmonic generation using transient wave simulation and nonlinear material properties. A YAG (lambda=1.06 micron) laser beam is focused on a nonlinear crystal so that the waist of the beam is inside the crystal.

Hexagonal Grating (Wave Optics)

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.

Beam Splitter

A beam splitter is used to split a single beam of light into two. One way of making a splitter is to deposit a thin layer of metal between two glass prisms. The beam is slightly attenuated within the layer, and split into two paths. In this example, the thin metal layer is modeled using a transition boundary condition which reduces the memory requirements. Losses in the metal layer are also ...

Time-Domain Modeling of Dispersive Drude-Lorentz Media (Wave Optics)

This tutorial shows how to solve the full time-dependent wave equation in dispersive media such as plasmas and semiconductors. The 2D TM in-plane wave model solves for the vector potential from the wave equation and for an auxiliary electric polarization density from an ordinary differential equation. The geometry consists of a single dispersive slab with a sub-wavelength slit in it. Periodic ...