Enhanced Dynamic Performance of Quantum Dot Semiconductor Lasers Operating on the Excited State

Abstract

International audienceThe modulation dynamics and the linewidth enhancement factor of excited-state (ES) lasing quantum dot (QD) semiconductor lasers are investigated through a set of improved rate equation model, in which the contribution of off-resonant states to the refractive index change is taken into account. The ES laser exhibits a broader modulation response associated with a much lower chirp-to-power ratio in comparison with the ground-state (GS) lasing laser. In addition, it is found that the laser emission in ES reduces the linewidth enhancement factor of QD lasers by about 40% than that in GS. These properties make the ES lasing devices, especially InAs/InP ones emitting at 1.55 μm, more attractive for direct modulation in high-speed optical communication systems

Analytic Characterization of the Dynamic Regimes of Quantum-Dot Lasers

“…This behavior shows that the detailed balance of the in and out-scattering rates plays a crucial role in determining the dynamics for moderate to high scattering rates. This is an important result as most models usually neglect this dependence and use constant in and out-scattering rates [26][27][28]. Those models cannot describe the third regime of quantum-dot laser dynamics.…”

Influence of inhomogeneous broadening on the dynamics of quantum dot lasers

“…However, in the second regime where the broadening linewidth is larger than the GS-ES 1 separation, the modulation bandwidth is slightly enhanced while the resonance peak appears in the responses. This difference is attributed to the carrier contribution of the ES, which is known to lead to a broader modulation bandwidth [19], [25]. As usually performed in experiments, we employ the well-known modulation transfer function described in [26] to fit the AM responses, in order to derive the resonance frequency R f as well as the damping factor Γ .…”

Enhanced Modulation and Noise Characteristics in 1.55 µm QD Lasers using Additional Optical Pumping

“…A research report has also revealed that via band structure engineering, the dynamic characteristics of QD lasers can be tailored [14]. Several structural and technical solutions such as using tunneling injection [15], pdoping [16], two sections gain lever [17], injection locking [18], or operating at excited state emission [19] have been suggested to overcome the mentioned restrictions on the modulation bandwidth of QD lasers. One of technical suggestions for improving the modulation response of QD laser is optical locking.…”