Ultrashort Pulse Generation by Gain Switching using Spice Simulator

Gain switching characteristics of quantum well (QW) lasers diode is described by using a SPICE equivalent circuit model which is based on the three-level rate equations. Effects of some laser diode parameters and dc and rf drive conditions on the full-width half maximum (FWHM) of gain switched pulses are investigated. It is shown that FWHM of pulses decrease as the rf current increased whereas these pulses increase as the dc bias is increased. FWHM decreases also for small value of gain compression parameter and spontaneous coupling factor. However, the variation in carrier lifetime in the well does not significantly affect the FWHM of generated pulses