TABLE OF CONTENTS The large-signal circuit model is derived from the rate equation by translating physical parameters of the laser, such as photons and carriers, into circuit variables, such as voltages and currents. A detailed explanation of the derivation is given in Section 15.14. The large-signal circuit model used in this book is shown in Fig. 15.3.
The circuit model of package and chip parasitics can be combined with the laser circuit model at its input port. The injection current reaching the active region, after passing the parasitics model, is denoted by I. The term C sc denotes the space-charge capacitance, I sp is the spontaneous emission current term, I g is the stimulated emission current term, and R ph is the photon-decay (absorption and scattering loss) resistance. The term ? I sp is the spontaneous emission current coupled in the lasing mode, the term T ns( dl sp/dt) represents the carrier build-up/depletion effect, V j is the junction voltage, and S n is the normalised output photon density ( ? intensity and power). The capacitor C ph is the energy storage element that describes the photon build-up/depletion effect. This large-signal circuit model is constructed by using symbolically-defined devices (SDD) in HPMDS [ [41]], which allows nonlinear dependent sources to be implemented. Several application examples of how the large-signal circuit model...
