MODELLING AND SIMULATION OF P-I-N QUANTUM DOT SEMICONDUCTOR SATURABLE ABSORBER MIRRORS

摘要： Semiconductor saturable absorber mirror (SESAM) based on InAs quantum dot (QD) is important in designing fast mode-locked laser devices. A self-consistent time-domain material travelling-wave (TDTW) model for the simulation of self-assembled QD-SESAM is developed. The 1-D TDTW model takes into consideration the time-varying QD optical susceptibility, refractive index variation resulting from the intersubband free-carrier absorption, homogeneous and inhomogeneous broadening. The carrier concentration rate equations are considered simultaneously with the travelling wave model. The model is used to analyze the characteristics of 1.3-μm p-i-n QD InAs-GaAs SESAM. The ?eld distribution resulting from the TDTW equations, in both the SESAM absorbing region and the distributed Bragg re?ectors, is obtained and used in ?nding the device characteristics including the modulation depth and recovery dynamics. These characteristics are studied considering the e?ects of QD surface density, inhomogeneous broadening, the number of QD absorbing layers, and the applied reverse voltage. The obtained results, based on the assumed device parameters, are in good agreement, qualitatively, with the experimental results.