Temperature dependence of refractive indices of Al0.9Ga0.1As and In0.53Al0.1Ga0.37As in the telecommunication spectral range

In this work, we determine the temperature dependence of refractive indices of In0.53Al0.1Ga0.37As and Al0.9Ga0.1As semiconductor alloys at telecommunication wavelengths in the range from room temperature down to 10 K. For that, we measure the temperature-dependent reflectance of two structures: with an Al0.9Ga0.1As/GaAs distributed Bragg reflector (DBR) designed for 1.3 µm and with an In0.53Al0.1Ga0.37As/InP DBR designed for 1.55 µm. The obtained experimental results are compared to DBR reflectivity spectra calculated within the transfer matrix method to determine refractive index values. We further show that changes due to the thermal expansion of the DBR layers are negligible for our method.