TEMPERATURE-DEPENDENT REFRACTIVE INDICES OF OPTICAL PLANAR WAVEGUIDES

The variation of refractive indices with temperature in polymer waveguides on silicon substrate is presented. It is among the first measurement done using advanced prism coupler with temperature-controlled system. The refractive index n, thickness and birefringence properties of the material have been studied in the temperature range of 30°C to 80°C. An apparent reduction of the refractive index with temperature of the material was observed, while there was no significant thickness-variation in the film coating. This behavior might be attributed to the temperature activated orientation mobility of the atoms of the polymer. The polarization anisotropy readouts are consistent with that would be expected of the TE and TM modes. The refractive index and thickness were examined as a function of spin coating parameter of the polymer. Temperature induced changes in nTE and nTM were studied for different planar waveguides parameters. The measured dn/dT coefficient of the polymer material matches with the value from the manufacturer.