波导厚度变动、偏振变动以及折射率变动脱敏高分子宽带耦合器设计

针对高分子光波导在制造工艺中波导芯厚度难以控制、芯层和包层的折射率差变动时的随机性以及材料各向异性引起的偏振态依赖性等实际问题,提出了采用抗波导芯厚度误差、抗折射率差变动和抗偏振变动的宽带波导耦合器回路结构的解决方案,给出了设计的理论和方法。在实测数据的基础上,进行了带宽为120nm的3dB氟化聚酰亚胺波导耦合器设计。由该器件的三维BPM仿真结果表明,在上述带宽上,波导芯厚度的变动范围为7～8μm、相对折射率差变动范围为0 24%～0.30%,两个正交偏振态都具有(50±2.0)%功率输出比的良好特性。

Polarization-independent and thickness- insensitive and index difference-independent broad-band fluorinated polyimide waveguide coupler

According to the polarization of polyimide material, thickness fluctuation of the waveguide's core, index difference fluctuation of the waveguide's core and cladding in polyimide optical waveguide preparation process, a statistical optimum design method is suitable for polarization-independent, thickness-insensitive and index difference-independent for broad-band waveguide coupler is proposed. Using the method, a fluorinated polyimide waveguide 3dB coupler for 1490～1610nm is designed based on measurement of fluorinated polyimide characteristics. The design result is verified by the 3D-BPM simulation, and shows that the coupling ratio of (50±2.0)% for the two orthogonal polarization is realized, in the 120nm waveband and thickness fluctuation region of 7～8μm, index difference fluctuation region is 0.24%～0.30%.