InAs/InGaAs/GaAs quantum dot lasers of 1.3μm range with enhanced optical gain

Kim

Phys. Status Solidi (c)

et al. 2009

Multiple InAs/GaAs self‐assembled quantum dots (QDs) with vertically stacked structure are grown by molecular beam epitaxy and the effects of GaAs interlayer thickness variation on optical properties are studied. The growth conditions are optimized by in‐situ RHEED, AFM, and PL measurement. The five InAs QD layers are embedded in GaAs and Al0.3Ga0.7As layer. The PL intensity is increased with increasing GaAs interlayer thickness. The thin GaAs interlayer has strain field, the strain‐induced intermixing of indium atoms in the InAs QDs (blue‐shift) can overcompensate for the effect on the increased QD size (red‐shift) (H. Heidemeyer et al. Appl. Phys. Lett. 80, 1544 (2002); T. Nakaoka et al. J. Appl. Phys. Lett. 96, 150 (2004) [1, 2], respectively). For the interlayer thickness larger than about 7 nm, the blue‐shifts are correlated to the dominant high‐energy excited state transitions due to the successive state filling of the ground and higher excited states in the QDs. The energy separation of double PL peaks, originated from two different excited states, was kept at around 50 meV at room temperature. A possible mechanism concerning this phenomenon is also discussed. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Section: Methodssupporting

confidence: 76%

Effect of GaAs interlayer thickness variations on the optical properties of multiple InAs QD structure

Kim

Phys. Status Solidi (c)

et al. 2009

“…The cavity is 1 mm long with a 2 µm-wide waveguide, and the active region is based on a dots-in-a-well structure including 10 InAs QD layers grown by molecular beam epitaxy (MBE) embedded in InGaAs quantum wells. 29 The optical spectra of both lasers are shown in FIG. 1 (a) and (b), their LI curves being represented in the insets.…”

confidence: 99%

Multimode optical feedback dynamics of InAs/GaAs quantum-dot lasers emitting on different lasing states

et al. 2016

Self Cite

Quantum dot lasers are envisioned to be the next generation of optical transmitters used for short-reach communication links, owing to their low threshold current and high temperature operation. However, in a context of steady increase in both speed and reach, quantum dot lasers emitting on their upper energy levels have been recently of greater interest as they are touted for their faster modulation dynamics. This work aims at further evaluating the potential impact of such lasers in communication links by characterizing their long-delay optical feedback responses as well as the role of the lasing states on the multimode dynamics of InAs/GaAs quantum-dot Fabry-Perot devices sharing the same design. Results unveil that the excited-state laser shows a much larger sensitivity to optical feedback, with a more complex route to chaos, and a first destabilization point occurring at lower feedback strengths than for a comparable ground-state laser, which remains almost unaffected.

IEEE J. Quantum Electron.

“…The component under investigation was a ridge-waveguide QD SOA of length 2 mm and width 7 m. The active layer consisted of five sheets of self-organized InAs dots grown on GaAs and overgrown with a 5-nm InGaAs layer [9]. Each layer had a dot surface density of 4 10 cm and the dot ensemble displayed a ground state emission wavelength centered at 1260 nm and with an inhomogeneous linewidth of 90 nm.…”

Section: Experiments and Sample Detailsmentioning

confidence: 99%

Dynamic Spatiotemporal Speed Control of Ultrashort Pulses in Quantum-Dot SOAs

Gehrig

Poel

Mørk

et al. 2006

Abstract-We present theoretical and experimental results on the propagation of ultrashort pulses in quantum-dot (QD) laser amplifiers. The propagation time of the light pulses is controlled by the pulse itself (self-induced speed control) or by injection of a second pump pulse (external speed control). Our simulations on the basis of spatially and temporally resolved QD Maxwell-Bloch equations reveal that the excitation and relaxation dynamics induced by the propagating pulse or a pump pulse within the active charge carrier system leads to a complex gain and index dynamics that may either speed up or slow down the propagating light pulse. The physical effects allowing for the dynamic speed control could be ascribed to complex (coherent and incoherent) level dynamics leading to dynamic gain saturation and index dispersion. The dependence of the propagation time on injection current density and pulse energy is discussed. The numerical results of pulse reshaping and propagation times in the gain and absorptions regime are compared to experimental results.