Recent advances in electrooptic polymer modulators incorporating highly nonlinear chromophore

Based on a nonlinear optical polymer with a highly nonlinear chromophore (CLD) dispersed in an amorphous polycarbonate (APC), we have developed electrooptic (EO) polymer modulators operating at 1550-nm wavelength with low loss and good thermal stability. By incorporating polymer insulation layer, push-pull poling was successfully performed without film damages. We also demonstrated that the propagation loss of the EO polymer waveguide could be reduced as low as 1.2 dB/cm at 1550 nm when the large core waveguide structure was incorporated. The long-term reliabilities of the EO polymer modulator made of CLD/APC polymer were investigated. When the modulator was hermetically sealed in an inert gas, the V_π change of a Mach-Zehnder modulator was negligible over 30 d of operation with 20-mW exposure to the waveguide input. In the thermal stability measurement, 25% V_π increase was observed from the sample heated to 60°C over 40 d, though the sample left at room temperature showed no decay of nonlinearity