Optimized Design of Temperature-Insensitive Optical Waveguide Coupler with 120-nm Bandwidth Using Fluorinated Polyimide

Method for designing optimized temperature-insensitive optical waveguide couplers by use of fluorinated polyimide is presented. Based on measured temperature and dispersion characteristics of fluorinated polyimide, a 3-dB waveguide coupler with a 120nm bandwidth with minimal temperature variance is designed and verified through simulation based on three-dimensional beam propagation. The coupling ratio of the theoretical device is 50 +/- 0.7% in the waveband 1490 ~ 1610 nm and the temperature range -10 ~ 40 °C. [Optical Society of America ]