Improved FBG Polarimeter Design Evaluated Using VCM Extension to Elliptical Polarization

Polarimeters for measuring the Stokes parameters have evolved significantly over the years from a variety of bulk-optic configurations to a number of elegant in-fiber designs. In this paper, we exploit recent advances in tilted fiber Bragg grating (FBG) technology to propose an improved in-line polarimeter that samples more than four detected beams with only two tilted FBGs. Based on theoretical analysis and simulation utilizing an extended formulation of the Volume Current Method (VCM), we demonstrate that this design reduces average Stokes vector errors by 20% for every state of polarization (SOP), facilitating monitoring at lower signal to noise ratios (SNRs).