Numerical analysis of the effects of carrier dynamics on the switch-on and gain-switching of quantum dot lasers

The paper analyses theoretically the quenching of the ground state (GS) power observed in InAs/GaAs quantum dot lasers when emitting simultaneously from both ground state and excited state. The model, based on a set of rate equations for the electrons, holes, and photons, shows that the power quenching is caused by the different time scales of the electron and hole intra-level dynamic, as well as by the long transport time of the holes in the GaAs barrier. The results presented also evidence how the very different dynamics of electrons and holes have other important consequences on the laser behavior; we show for example that the electron and hole carrier densities of the states resonant with lasing modes are never clamped at the threshold value, and that the damping of relaxation oscillations is strongly influenced by the hole dynamics.

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Output power of a quantum dot laser: Effects of excited states

Asryan

2015

Journal of Applied Physics

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A theory of operating characteristics of quantum dot (QD) lasers is discussed in the presence of excited states in QDs. We consider three possible situations for lasing: (i) ground-state lasing only; (ii) ground-state lasing at first and then the onset of also excited-state lasing with increasing injection current; (iii) excited-state lasing only. The following characteristics are studied: occupancies of the ground-state and excited-state in QDs, free carrier density in the optical confinement layer, threshold currents for ground-and excited-state lasing, densities of photons emitted via groundand excited-state stimulated transitions, output power, internal and external differential quantum efficiencies. Under the conditions of ground-state lasing only, the output power saturates with injection current. Under the conditions of both ground-and excited-state lasing, the output power of ground-state lasing remains pinned above the excited-state lasing threshold while the power of excited-state lasing increases. There is a kink in the light-current curve at the excited-state lasing threshold. The case of excited-state lasing only is qualitatively similar to that for single-state QDs-the role of ground-state transitions is simply reduced to increasing the threshold current.

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Numerical analysis of the effects of carrier dynamics on the switch-on and gain-switching of quantum dot lasers

Cited by 3 publications

References 13 publications

Gain-switched short pulse generation from InAs-InP (1 1 3)B quantum dot laser excited state

Gain-switched short pulse generation from InAs-InP (1 1 3)B quantum dot laser excited state

Ground-state power quenching in two-state lasing quantum dot lasers

Output power of a quantum dot laser: Effects of excited states

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