Optimized Design of Polarization-Independent and Temperature-Insensitive Broadband Optical Waveguide Coupler by Use of Fluorinated Polyimide

A statistically optimized design method suitable for a polarization-independent and temperature-insensitive broadband waveguide coupler is proposed. By use of this method, a fluorinated polyimide waveguide 3-dB waveguide coupler for 1490 ~ 1610 nm application is designed by optimizing polarization and temperature fluctuation. The validity of the design is verified through simulation based on the three-dimensional beam propagation method (3D-BPM), which revealed a coupling ratio of 50 +/- 0.8% in a 120-nm bandwidth in the temperature range -10 to 40 (degree)C for both orthogonal polarizations.