The problem of noise analysis in measuring the group delay introduced by a dispersive optical element by use of white-light interferometric cross correlation is investigated. Two noise types, detection noise and position noise, are specifically analyzed. Detection noise is shown to be highly sensitive to the spectral content of the white-light source at the frequency considered and to the temporal acquisition window. Position noise, which arises from the finite accuracy of the measurement of the scanning mirror’s position, can severely damage the estimation of the group delay. Such is shown to be the case for fast Fourier transform–based estimation algorithms. A new algorithm that is insensitive to scanning delay errors is proposed, and subfemtosecond accuracy is obtained without any postprocessing.
© 2002 Optical Society of America
Vincent Laude, "Noise analysis of the measurement of group delay in Fourier white-light interferometric cross correlation," J. Opt. Soc. Am. B 19, 1001-1008 (2002)