FIMMWAVE is a generic, robust, fully vectorial mode finder for 2D+Z waveguide structures, which may be of almost any geometry or material including SOI, polymer & etched GaAs/AlGaAs waveguides in addition to single and multimode fibers.

  • Vectorial solution of (near) arbitrary 3D waveguides
  • Accurate also for higher order modes and large multimode waveguides
  • Many different mode solver engines including FMM, FEM, & FDM Methods
  • Complex engines for waveguides with complex refractive index materials, including metals
  • Calculation of material stress, thermal & electro-optic effects
  • Automatic calculation of confinement factor, mode loss, group index, dispersion etc.
  • Parameter scanners for rapid design
  • Accurate solutions even for devices with thin layers, weakly coupled, and near cut-off
  • Comprehensive materials database
  • Diagonal and general tensor anisotropy supported
  • Rigorous bend mode solver
  • Far Field Calculator

FIMMWAVE contains a variety of robust and computationally efficient solvers optimized for either generic structures often encountered in opto-electronics, or fibers with generic refractive index profiles.

A lot of original work has been put into this product to make these solvers extremely reliable with the option of using approximate versions of these methods - ideal for rapid prototyping.

FIMMWAVE combines both methods based on semi-analytical techniques, which allow tackling of problems with strong variations in refractive index, thin layers, etc., with other more numerical methods such as Finite Difference or Finite Element. This allows FIMMWAVE to offer enough flexibility to solve accurately a very wide variety of waveguides.

The program comes with sophisticated visualization tools for easily analyzing mode profiles, such as quick previews, 2D contour plots, rotatable 3D mesh plots etc. ASCII files of most results may be generated for import to other programs.


PC: x86+x64: Win2000/XP/Vista/7, 1GB RAM, 2GHz or better recommended.

Calculation Methods

The FMM Solver: - This solver, based on the Film Mode Matching method, is optimized for rectangular waveguide structures commonly seen in integrated optics. It is fully vectorial capable of solving structures with complex refractive index such as metallic components, or even radius of curvature.

This solver can accurately calculate modes that are near cut-off in the lateral direction without loss of accuracy or an increase in computation time. Such modes cannot be modeled accurately with Finite Element or Finite Difference methods.

The FDM Solver: - The FDM Solver brings the Finite Difference method to FIMMWAVE. It can model both real and lossy materials, supports PML absorbing boundary conditions, and anisotropic dielectric tensors (diagonal tensor).

Effective Index Solver: - This well known approximate method is both a fast and reliable way of finding estimates for 3D modes for near 2D waveguides (many ridge structures fit into this category). This home grown solver is extremely robust; in particular it can deal with structures with completely decoupled cores.

The FEM Solver (Opt 9): - The FEM Solver brings the Finite Element method to FIMMWAVE and is offered as an optional add-on to the base module. Ideal for structures with curved interfaces or unusual shapes such as holey fibers.

Vectorial Fibre Solver (Opt 06): - This option houses two vectorial engines for solving generic circular waveguides with arbitrary refractive index. The first is based on a rigorous solution to the vectorial wave equation in cylindrical co-ordinates. It will find all the modes of such structures using metallic or transparent boundaries. Although it is a fully vectorial solver it exploits the circular symmetry, thus making it an almost instant calculation.

The second engine employs a Finite Difference technique to solve the vectorial wave equation. It can model fibers of arbitrary refractive index profiles (real or complex) and anisotropic media. Large multimode fibers, metal coated fibers are just a couple of difficult applications that this solver can easily handle.

Stress Solver (opt 10): - The Stress Solver for FIMMWAVE allows the user to calculate the stress fields in a waveguide and the consequential perturbation of the waveguide modes. This Finite Element method based solver supports thermally induced stress fields – typically generated during cooling of a device constructed from materials with different thermal expansion coefficients.

Applications are SOI waveguides and PANDA Fibers among others.

Thermal Profiler and EO module (opt 07):- This option allows the user to study the thermal or electro-optic response of the waveguides. The change in refractive index profile of the structure is calculated by a 2D Poisson Solver before the subsequent modes are calculated.

Design Utilities

Parameter Scanners:- These tools allow the user to rapidly generate design curves of almost any calculated parameter as a function of almost any input parameter or dimension. Parameter scanners permit design optimization in a rapid simple manner. Here we model the change in effective index of the supermodes of a twin ridge waveguide as the waveguide ridges are separated.


A new generic optimization tool Kallistos is now available, capable of automatically improving the characteristics of any FIMMWAVE waveguide by altering its dimensions and refractive indices. For more information on Kallistos please click here.

A small sample of publications using results from FIMMWAVE

"Polarization-selective grating excitation of plasmons in cylindrical optical fibers" - Y. Shevchenko, C. Chen, M. A. Dakka, J. Albert. Optics Letters, vol. 35, No. 5, March 1 2010 , pp.637-639

"Compact and highly-efficient polarization independent vertical resonant couplers for active-passive monolithic integration" - M. Galarza, D. Van Thourhout, R. Baets, M. Lopez-Amo. Optics Express, vol. 16(12) 2008 , pp.8350-8358

"Compact and low loss silicon-on-insulator rib waveguide 90° bend" - Yusheng Qian, Seunghyun Kim, Jiguo Song, Gregory P. Nordin and Jianhua Jiang. Optics Express, Vol. 14, No. 13, June 2006, pp. 6020-6028

"Design of modulation-doped SiGe/Si optical modulator integrated in a submicrometer silicon-on-insulator waveguide" - Delphine Marris, Eric Cassan, Laurent Vivien, Daniel Pascal, Alain Koster, Suzanne Laval. Optical Engineering, Vol.44(8), 084001, August 2005

"All-Optical Efficient Wavelength Conversion Using Silicon Photonic WIre Waveguide" - K. Yamada, H. Fukuda, T. Tsuchizawa, T. Watanabe, T. Shoji and S. Itabashi. IEEE Photonics Technology Letters, Vol. 18, No. 9, pp. 1046-1048, May 2006

"Hollow-Core Waveguides and 2-D Waveguide Arrays for Integrated Optics of Gases and Liquids" - Holger Schmidt, Dongliang Yin, John P. Barber, Aaron R. Hawkins. IEEE Journal of Selected Topics in Quantum Electonics, V11, No. 2, March/April 2005