Silicon-based polarization analyzer by polarization-frequency mapping

Abstract

Measuring states of polarizations (SOPs) is a fundamental requirement in high capacity optical communications, optical imaging, and material characterization. However, most of the existing methods focused on the assembly of spatial optical elements, making the system bulky and complex. Alternatively, the integrated methods were mainly presented by plasmonic nanostructures or metasurfaces, difficult to integrate with commonly used silicon photonic devices. For large-scale inter-chip optical interconnections, the silicon-based polarization analyzers are in demand and in its infancy. Here, a silicon-based polarization analyzer by polarization-frequency mapping is put forward. The basis vectors of polarization are mapped to two frequencies by thermally tuned phase shifters. The SOPs are retrieved from the frequency domain. The proposed polarization analyzer is demonstrated experimentally and can measure SOPs in the entire C-band. The scheme is compatible with the CMOS fabrication process, making it possible to be integrated with other silicon-based devices monolithically.