Characterizing polarization controllers with Mueller matrix polarimetry

A system for characterizing polarization controllers and other fiber components with Mueller matrices is presented. Most polarization controllers, such as lithium niobate modulators or PLZT electro-optical modulators, exhibit a wide range of polarization behaviours at constant drive voltage including elliptical retardance, polarization dependant loss (PDL), and depolarization (coupling of polarized light into an unpolarized exiting component). Specifying the half wave voltage for such devices describes their desired characteristic, an electrically addressable retardance, but not the undesired characteristics. Devices with complex polarization behaviours require a similarly comprehensive description of their polarization effects. We present example measurements that demonstrate how the Mueller matrix as a function of voltage provides a complete description of the desired retardance and the undesired PDL. Such polarization controller Mueller matrices can be multiplied with Mueller matrices for other photonic components to quantify how component polarizations interact.