What is "autocorrelator"

n. 1 (context electronics English) A device that modifies a signal with a delayed copy of itself in order to detect any periodic signal hidden in the noise 2 (context electronics English) A device that uses interferometry to detect autocorrelation of optical beams

A real time interferometric autocorrelator is an electronic tool used to examine the autocorrelation of, among other things, optical beam intensity and spectral components through examination of variable beam path differences. See Optical autocorrelation.