English: The operation of a polarization independent isolator, showing the propagation of light through the structure. The forward travelling light is shown in blue, and the backward propagating light is shown in red. The rays were traced using an ordinary refractive index of 2, and an extra-ordinary refractive index of 3. The wedge angle is 7 degrees. The first birefringent wedge has its slow axis vertical and its fast axis horizontal. The Faraday rotator is a 45 degree rotator. The second birefringent wedge has its slow axis at 45 degrees and its fast axis at -45 degrees. Therefore light travelling in the forward direction experiences symmetric refraction. Due to the non reciprocal rotation, the light travelling in the backward direction experiences asymmetric refraction, hence is diverged. Upload drew the image