Spectral filtering for ultra-fast mode-locking in the normal dispersive regime

A theoretical model is developed which characterizes the physical process responsible for generating ultra-short, high-energy, mode-locked pulses in a normal GVD laser cavity with spectral filtering. Two physical parameters are critical to achieving optimal performance: the ratio of the filter bandwidth to the gain bandwidth and the placement of the output coupler in the laser cavity. The spectral filtering allows for the high-energy of typical normal GVD laser cavities to be maintained while the pulse intensity doubles and the FWHM reduces by an order of magnitude. This phenomenon is generic and ubiquitous to normal GVD mode-locking. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)