A theory predicting the durations of Pulses from actively mode-locked lasers.
The Kuizenga Siegman theory is a theoretical treatment which allows to calculate the pulse duration of an actively mode-locked laser. The basic underlying idea is that active Mode locking involves two competing mechanisms acting on the duration of the circulating pulse:
The Modulator causes a slight Attenuation of the wings of the pulse, effectively reducing the pulse duration.
Due to its limited Gain bandwidth, the gain medium tends to reduce the Bandwidth of the pulse and thus to increase the pulse duration.