DYNAMIC ANALYSIS OF ERBIUM-DOPED OPTICALLY PUMPED WAVE-GUIDE LASERS USING A TIME-DOMAIN TRAVELING-WAVE MODEL

A simple and straightforward dynamic model of Er3+-doped optically pum ped waveguide lasers using a time-domain algorithm is developed. The t heoretical model is based on (a) time-dependent rate equations of a qu asi-two-level system for the population densities and (b) time-depende nt travelling wave equations for the pump and signal power which are s olved simultaneously in the time domain. In addition, the longitudinal distribution of spontaneous emission noise is also taken into conside ration. Using the fast Fourier transform, the spectrum profile of the time-domain signal power is calculated. In this paper, the transient r esponses of population densities, pump and signal power are investigat ed for Er3+-doped Ti:LiNbO3 waveguide lasers. To demonstrate the sophi stication of this time-domain model, the influence of the cross-couple d effect of the travelling waves due to the optical feedback of an etc hed grating is also studied. Dynamic response of the waveguide laser w ith and without a grating are compared.