BIFROST is a Python library that provides a set of data, methods, and classes for the simulation of polarization mode dispersion in optical fibers. Silica-based fibers whose core and/or cladding are doped with germanium oxide or with fluorine can be simulated.
Specifically, the fibers.py module provides the following classes (see their individual documentations for more details):
FiberLength, the base class that stores information about the fiber geometry and conditions and calculates birefringences and Jones matrices;FiberPaddleSet, a set of fiber paddles like ThorLabs FPC563 that manually controls the polarization;Rotator, providing arbitrary rotations; andFiber, an implementation of the hinge model of optical fibers that alternates hinges with long birefringent sections. This class includes theFiber.random()method for generating random optical fibers following user specifications.
This repository also includes the example Jupyter notebook for getting started.
The library requires NumPy; you may also find py_pol and plotly useful, as detailed below. The last example in the example notebook requires SciPy and MatPlotLib.
To aid in understanding the results of these simulations, I've found it best to use the package py_pol. The example Jupyter notebook shows a few examples of the use of this package, especially translating the Jones matrices generated by this package to Mueller matrices and Stokes vectors.
I have been especially interested in putting two sets of simulation results on the same Poincaré sphere. As best I can tell this is not supported in py_pol, but there is a quick and dirty fix: install plotly in your environment, and in the drawings.py file of your local install of py_pol, in the draw_poincare() method, set add_auxiliar = True by default on line 523. Then use code like I show in the examples notebook.
Another annoying caveat: one of the reasons py_pol is convenient is you can pass multiple objects around at the same time, e.g. E1 = J0 * E0 can represent the several Jones vectors resulting from one Jones vector E0 being multiplied by several Jones matrices J0. However, this fails if there are exactly two Jones matrices in J0. So be wary of trying to make direct comparisons between two Jones matrices.
Copyright (C) 2025 Patrick Banner.
This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program. If not, see https://www.gnu.org/licenses/.