Theory of generation of picosecond pulses by an injection laser with an external resonator in the mode-locking regime

A theoretical investigation is made of generation of a continuous sequence of picosecond pulses in the case of resonant high-frequency pumping of an injection laser with an external resonator. Multiple transit of a light pulse through the components of a ring resonator is considered and the parameters of a steady-state pulse are determined. The active medium is regarded as consisting of two parts, one of which exhibits weak nonlinear absorption. The problem is solved by an iteration method on a computer. A study is made of the influence of the laser parameters on the duration, asymmetry, and energy of the pulses. A comparison is made with experimental results.