sapphire oscillator in order to generate a single wavelength at 780 nm. The model offers a simple mechanism to investigate the impact of the variations of the input parameters (maximum amplification coefficient, pumping rate, loss coefficient, and pumping density) on the output pulse characteristics (delay time, pulse width, pulse build up time, duration and peaks maxima of the Nd3+ -YAG pumping laser). Moreover, this model allows studying the gain-switched Ti:sapphire output characteristics as being pumped by the second harmonic wavelength (532nm). Numerical results showed that the maxima of the output photon density, pulse width, delay time, and pulse duration are very much dependent on the power variations of the pumping source.