Fiber Birefringence


Birefringence dialog box

The “Birefringence” dialog box allows you to define parameters of the fiber
birefringence model. As described in the “Technical Background”, various
mechanisms contribute to fiber birefringence. You can simply define birefringence
values or follow one of the OptiFiber models.

To access this dialog box, do one of the following steps:

Step Action
1 Select “Birefringence” on the Simulation menu
2 Click the “Birefringence” icon in the “Navigator” pane , or
3 Access it by double-clicking in the “Birefringence” view tab.

Optical Fiber - Birefringence dialog boxThe elements and controls of the “Birefringence” dialog box options are described

Central Wavelength

Enter the central wavelength for the birefringence calculations.

User Defined

To characterize the birefringence phenomena without OptiFiber models, enter the
following coefficients:

  • Delta Beta – Difference between the propagation constants of the two
    orthogonally polarized modes
  • DGD – Differential Group Delay (DGD) related to fiber birefringence

Photoeleastic Constants

A group of constants characterizes photoelastic properties of the fiber: the Young
modulus, C coefficient, and Poisson ratio. This section is enabled when you intend to
use OptiFiber birefringence models.

Induced by Perturbation Parameters

This section refers to birefringence caused by intrinsic and extrinsic fiber

Intrinsic options:

  • Elliptical Core Deformation – Enter the Core Ellipticity parameter.
  • Thermal Stress – Enter the Differential Thermal Expansion Coefficient and Temperature Difference values.
  • Extrinsic options:
  • Bending Radius – Enter the bending radius.
  • Fiber Spooled with Tension – Enter the tension force value.
  • Transverse Pressure – Enter the transverse pressure value.


The birefringence calculations are performed over a spectral range around the
Central Wavelength value. You enter the spectral range and the number of calculation

See also the following sections in the Technical Background:

  • Fiber Birefringence Definition
  • Intrinsic Perturbations Birefringence
  • Elliptical Core Birefringence Definition
  • Internal Stress Birefringence Definition
  • Extrinsic Perturbation Birefringence
  • Lateral Stress Birefringence Definition
  • Bending Birefringence Definition
  • Bending Under Tension Birefringence Definition