Light-by-light polarization control using Stimulated Brillouin Scattering with retardance spectrum shaping

Abstract

The spectral broadening of a nonlinear polarization retarder based on the polarization dependent interactions of Stimulated Brillouin Scattering is proposed and demonstrated. Through phase-to-retardance conversion, it is shown that polarization can not only be controlled in a bandwidth wider than the natural Brillouin response, but it can also be tailored to provide a certain retardance profile. Broadening is achieved through the engineering of Brillouin phase frequency response via feedback pump regulation, unlike previous schemes based on amplitude and time delay control. Retardance broadening from 51 MHz (natural SBS interaction) to 0.9 GHz along with retardance flattening is demonstrated. This technique contributes to expand optical signal processing tools and opens new possibilities in all-optical switching and routing of data signals as well as in the field of microwave photonics.