Ultra-compact In-Line Scattering Polarimetry

In-line polarimeters perform non-destructive polarization measurements of optical signals, and play a critical role in monitoring and controlling the polarization environment in for example optical networks. While current in-line polarimeters are constructed with multiple optical components, either fabricated into an optical fiber or using free-space optics, we present here a novel architecture conducive to monolithic on-chip integration. This enables the scalable fabrication of high-performance polarization sensors with exceptional stability, compactness and speed. The method relies on the detection of the highly polarization-dependent scattered field of a sub-wavelength antenna array known as metasurface, and is shown here to provide polarization state measurements matching those of a state-of-the-art commercial polarimeter.