Abstract

Active modelocking of cw Nd:glass lasers usually results in a pulse train of 5-10 ps pulses^{1 2} following the Kuizenga-Siegman theory. By inserting a newly developed intracavity spectral filter to flatten the net gain profile, a regeneratively actively mode- locked Nd:glass laser produced transform-limited pulses as short as 310 fs. This corresponds to a pulse shortening by a factor of more than 20 in comparison to previously demonstrated actively mode-locked Nd:glass lasers. No Kerr lens modelocking is responsible for the reported pulse shortening. However, due to the flattened gain profile the modelocker reduces the pulse- width until a soliton is formed.

© 1994 Optical Society of America