6-H single-crystal silicon carbide thermo-optic coefficient measurements for ultrahigh temperatures up to 1273 K in the telecommunications infrared band

6H single-crystal silicon carbide (SiC) is an excellent optical material for extremely high temperature applications. Furthermore, the telecommunication infrared band (e.g., 1500-1600 nm) is an eye safe and high commercial maturity optical technology. With this motivation, the thermo-optic coefficient ∂n∂T for 6H single-crystal SiC is experimentally measured and analyzed from near room temperature to a high temperature of 1273 K with data taken at the 1550 nm wavelength. Specifically, the natural ́talon behavior of 6-H single-crystal SiC is exploited within a simple polarization-insensitive hybrid fiber-free-space optical interferometric system to take accurate and rapid optical power measurements leading to ∂n∂T data. The reported results are in agreement with the previously reported research at the lower <600 K temperatures.