Experimental investigation of thermo-optic effects in SiC and Si photonic crystal nanocavities

We experimentally investigate and compare the thermo-optic effects of silicon carbide (SiC) and silicon (Si) photonic crystal nanocavities on their resonant wavelengths over a temperature range of 25 °C to nearly 200 °C by using a laser source with a wavelength close to the telecommunication wavelength range of 1550 nm. The measured results clearly show that the shift in the resonant wavelength of the SiC cavity is significantly (by a factor of 3) less than that of the Si cavity for the same ambient temperature changes. In addition, the measured results provide direct estimates of the thermo-optic coefficients (dn/dT) for thin SiC and Si as 3.87×10(-5)/°C and 1.60×10(-4)/°C, respectively, for this temperature range.