“…The problem arises when different materials are combined to make these high temperature measurement probes, whether prior-art commercial electrical designs like packaged TCs or research community optical designs [4][5][6][7][8][9], e.g., sapphire fiber with gratings and external fiber packaging. Because fundamentally different materials have different Coefficient of Thermal Expansion (CTE) coefficients, CTE mismatch in the present probe designs leads to mechanical stresses and eventual probe failure.…”