Patent ID: 7551267

Claim:
A system for measuring a pulse length τ 0 of an ultra-short light pulse P 0 , comprising: a) an autocorrelation optical system adapted to receive a number of substantially similar light pulses P 0 and create from each light pulse two co-polarized beams having an associated optical path length difference ΔOPL that varies between light pulses to form an autocorrelation interference pattern representative of an autocorrelation of the light pulse; b) an LED detector adapted to detect the autocorrelation interference pattern and generate therefrom a raw autocorrelation signal S AR ; c) a signal-processing unit electrically coupled to the LED detector and adapted to form from the raw autocorrelation signal S AR a digital count signal S N representative of a number N C of counted peaks in the autocorrelation signals above the full-width half-maximum (FWHM); d) control electronics unit operably coupled to the autocorrelation optical system and the signal-processing unit and adapted to cause the varying ΔOPL and to provide a difference signal S Δ representative of the ΔOPL to the signal-processing unit; and e) wherein the signal-processing unit is adapted to calculate the pulse length based on ΔOPL and N C .