Polarization Dependence of Optical Properties of Single-Mode Polymer Optical Waveguides Fabricated under Different Processes at 1310/1550 nm

We experimentally investigate the polarization dependence of the optical properties of single-mode polymer optical waveguides. We compare two types of waveguides composed of the same polymer materials: Step-index square-core waveguides fabricated using the direct curing method and graded-index (GI) circular-core waveguides fabricated using the Mosquito method. We demonstrate that the GI circular-core single-mode waveguides exhibit remarkably small dependence of optical loss on the polarization angle, which is less than 0.1 dB polarization dependent loss (PDL) at both 1310 and 1550 nm wavelengths. This steady polarization property is attributed to the material stress free to the composing polymers during the fabrication process of the Mosquito method and to parabolic GI profile formed in symmetric circular core.