Modeling Interferometric Structures with Birefringent Elements: A Linear Vector-Space Formalism.

摘要

We outline a formalism for modeling structures containing birefringent elements and directional couplers. The traditional description of couplers (as single polarization devices with two input and output ports) and fibers (as single port devices with two polarizations) is generalized into a four-dimensional vector space with convenient coordinate transformations between the traditional views. This enables system modelers to introduce complex elements and scenarios under a single formalism, switching between the two traditional views with a single 4 x 4 matrix transformation. We generalize an earlier formulation to include extra degrees of freedom in rotation, coupling, and birefringence matrix operators. The technique is applied to a microwave photonics setting and a quantitative description is developed that illustrates how normal mode loss in the interferometer's couplers leads to a polarization-independent phase offset in the output arms.