Non-contact absolute internal distance measurement between two mirrors by using a low-coherence tandem interferometer (3rd Report)

Uncertainty budget

Abstract

An absolute measurement method for precisely measuring the internal distance between two plane mirrors is proposed by a tandem low-coherence interferometer. The measurement uncertainty of the proposed method is reported in this paper. It is considered that the main source of measurement uncertainty is coming from the use of the beam splitter. Hence, the uncertainty due to the correction value which is difference value between the refractive index of air and beam splitter that causes a length difference between mechanical and optical lengths is estimated. We also report the uncertainty budget for the influence the geometrical error and temperature.