Research
Dynamic Characterization of InAs/AlGaAs Broadband self-Assembled Quantum Dot Lasers
In this research we have solved the rate equations for InAs/AlGaAs broadband selfassembled quantum dot (QD) laser with considering the homogeneous broadening (HB) and inhomogeneous broadening (IHB) of the linear optical gain using fourth order Runge-Kutta method. We show that enhancing the injected current results in improving the dynamic characteristics, and increasing the steady-state photons, and show that with increase of the full width at half maximum (FWHM) of HB, the threshold current, turn-on delay and steady-state photons increase. Our calculation results also show that the simulated broadband selfassembled QD laser does not reach the complete steady-state when HB is near or equal to IHB.
Static Characterization of InAs/AlGaAs Broadband Self-Assembled Quantum Dot Lasers
In this paper we have studied the static-characteristics of InAs/AlGaAs broadband selfassembled quantum-dot laser diodes (SAQD-LDs) solving the rate equations numerically using fourth-order Runge-Kutta method. Energy level, size, and composition distributions of the InAs/AlGaAs broadband quantum-dots (QDs) are considered and their effects on Staticcharacteristics are investigated. Simulated results of static-characteristics show that nonlinearity appears in light-current characteristics whereas homogeneous broadening (HB) becomes equal to inhomogeneous broadening (IHB). Slope-efficiency increases as the HB heightens up to the IHB. Exceeding the HB from IHB results in degradation of light-current characteristics. In fact, InAs/AlGaAs broadband SAQD-LD has the best performance when HB is equal to IHB. Lightcurrent characteristics degrade and threshold current increases as the IHB enhances. We also investigate the effects of QD coverage on the laser performance and show that there is an optimum QD coverage in which the SAQD-LD operates with lowest possible threshold current and maximum output power as whatever the QD coverage enhances from that optimum amount, the threshold current increases and slope efficiency decreases.
