FIMMWAVE

Modes of Cylindrical Optical Fibres

Simulation with FIMMWAVE Cylindrical Solvers software

FIMMWAVE can calculate modes of circular optical fibres using its powerful range of cylindrical mode solvers.

Modes of a step-index fibre
Mode analysis: calculation of attenuation, dispersion, etc.
Modes of a graded-index fibre
Modes of an anti-guiding fibre
Importing a refractive index profile from a profiler

Modes of a step-index fibre

FIMMWAVE allows you to define the radial refractive index profile and calculate the modes of a step-index fibre extremely easily. You can conveniently define the fibre profile via the thickness and the refractive indices of the concentric shells.

The fibre modes can be found with the GFS Solver which uses Bessel functions and the FDM Fibre Solver which relies on a finite-difference method. Both are rigorous fully vectorial solutions, dealing correctly with both low and high index contrast profiles.

Step-index fibre designed in FIMMWAVE:
(left) geometrical view (right) refractive index profile

Mode profiles for the Ex-field component of (left) the fundamental TE-like mode
and (right) a higher-order mode of a step-index fibre calculated with the vectorial GFS Solver

Mode analysis: calculation of attenuation, dispersion, etc.

For each fiber mode, FIMMWAVE will provide you with extensive mode data, including mode loss, dispersion, effective core area, measurement of the mode width (FWHM, 1/e, 1/e2), etc.

A complex version of the FDM Fibre Solver is available, allowing you to model absorbing structures and plasmonic effects e.g. with metal claddings, and to calculate the associated mode losses.

Mode data for a non-lossy with parameters such as effective index, group index, dispersion, effective core area etc.

Modes of a graded-index fibre

Another example of design: you can define a graded-index profile by specifying the refractive index at different radial positions. FIMMWAVE will generate a continuously varying profile with an advanced spline fitting, shown below in the case of a graded-core fibre with a uniform cladding.

Graded-index fibre designed in FIMMWAVE:
(left) geometrical view (right) refractive index profile

Mode profiles of the first circularly-polarized mode of a graded-index fibre
(left) Ex field component (right) Ey field component calculated with the FDM Fibre Solver

Modes of an anti-guiding fibre

You can see below the profile of an anti-guiding fiber relying on a periodic arrangement of layers. The modes are confined in the low-index region at the center.

Anti-guiding fibre designed in FIMMWAVE: design and mode list
(top-left) geometrical view (top-right) refractive index profile (bottom) mode list

Mode profiles: (left) Ex field component of the fundamental TE-like mode (right) Ex field component of the HE12 mode.

Importing a refractive index profile from a profiler

FIMMWAVE can conveniently and easily import a radial refractive index profile measured with a profiler. You will find below an example of an imported profile, interpolated with a spline fitting.

Fibre profile imported into FIMMWAVE and fitted with a spline interpolation

More publications 

Click here to find publications that include FIMMWAVE simulations of optical fibres on Google Scholar.