Abstract

Fabry-Perot interferometers are a sensitive tool to measure extremely slight changes of the optical cavity length. Variations in the temperature lead to small changes of the optical path i.e. the cavity length and the refractive index and thus to a detuning of the Fabry-Perot resonator. Whereas for most of the insulating optical materials the refractive index depends only weakly on the temperature the small bandgap semiconductors such as Si, GaAs, GaP, Ge etc. exhibit not only a high refractive index of about 3.5 but also typical thermal changes of the refractive index of about 10^-4/K which is much larger than the thermal expansion coefficient (typical in the 10^-4/K range)

© 1988 Optical Society of America