Birefringence matrix for a twisted single-mode fiber: Geometrical contribution

The elastic twisting of a fiber in the cold condition causes two effects: a geometrical rotation of the birefringence axes of the fiber with the twist rate and a torsional stress. In this work, considering only the geometrical contribution, we derive a matrix model based on classical polarization optics. The predictions of this model, useful for fibers with a low twist rate, are compared with experimental results.