Time-resolving wavelength chirp with Fabry-Perot etalons and gratings: a theoretical approach

Basic dynamic properties of Fabry-Perot (FP) etalons and gratings are investigated for a square-wave shaped input pulse with a linearly changing wavelength. It is shown that for the chirp rates present in distributed feedback (DFB) laser pulses a simultaneous good resolution in the wavelength and time domain is attainable with an etalon due to its small FWHM time-bandwidth product of 0.11. This is not possible with the grating, which has a time∞bandwidth product of 0.89. A simulation of time resolving the dynamic chirp of a DFB laser pulse is presented. The result is compared to the actually calculated incident wavelength variation. The dynamic aspects of FP etalons and gratings for time resolving the wavelength chirp in laser pulses are given