Polymer Waveguide Birefringence Modulators

Birefringence modulators for controlling the phase retardation between transverse electric (TE) and transverse magnetic (TM) polarizations are demonstrated based on polymeric waveguides. Highly birefringent polymer material is incorporated to increase the polarization dependence of the thermo-optic (TO) effect. The TO coefficient for each polarization is measured using a Mach-Zehnder device, and the polarization dependence of the TO effect is found to be 1.0 × 10^-5/°C. By applying 70 mW of heating power with an integrated heater, π-phase difference is achievable between the TE and TM polarizations. For 45° input polarization, the output polarization is successfully modulated to cover the entire Poincare sphere.