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.