Analysis of double laser emission occuring in 1.55 μm InAs-InP (113)B quantum dot laser

In this paper, a theoretical model based on rate equations is used to investigate static and dynamic behaviors of InAs–InP (113)B quantum-dot (QD) lasers emitting at 1.55 m. More particularly, it is shown that two modelling approaches are required to explain the origin of the double laser emission occurring in QD lasers grown on both, GaAs and InP substrates. Numerical results are compared to experimental ones by using either a cascade or a direct relaxation channel model. The comparison demonstrates that when a direct relaxation channel is taken into account, the numerical results match very well the experimental ones and lead to a qualitative understanding of InAs–InP (113)B QD lasers. Numerical calculations for the turn-on delay are also presented. A relaxation oscillation frequency as high as 10 GHz is predicted which is very promising for the realization of directly modulated QD lasers for high-speed transmissions

Optical properties and morphology of InAs ∕ InP (113)B surface quantum dots

We report on long-wavelength photoluminescence(PL) emission at room temperature from self-organized InAssurfacequantum dotsgrown by gas-source molecular beam epitaxy on a GaInAsP∕InP (113)B substrate. The influence of arsenic pressure conditions during growth on the PL emission of surfacequantum dots is detailed as well as oxide/contamination layer formation after growth. Experimental results are in good agreement with six-band k⋅p theory in the envelope function approximation.This work was supported by the SANDIE European Network of Excellence

41 GHz and 10.6 GHz low threshold and low noise InAs/InP quantum dash two-section mode-locked lasers in L band

International audienceThis paper reports recent results on InAs/InP quantum dash-based, two-section, passively mode- locked lasers pulsing at 41 GHz and 10.6 GHz and emitting at 1.59 lm at 20°C. The 41-GHz device (1 mm long) starts lasing at 25 mA under uniform injection and the 10.6 GHz (4 mm long) at 71 mA. Their output pulses are significantly chirped. The 41-GHz laser exhibits 7 ps pulses after propagation in 60 m of a single-mode fiber. The 10.6-GHz laser generates one picosecond pulses with 545 m of a single-mode fiber. Its single side-band phase noise does not exceed -80 dBc/Hz at 100 kHz offset, leading to an average timing jitter of 800 fs

Échantillonnage électrooptique sur les circuits III-V

International audienc

Etude des centres à électrons créés par irradiation de protons dans InP:n

Schottky diodes made on n type LEC InP samples have been irradiated by 100 keV H+ at 6 K, 77 K and 300 K and the created electron traps studied by transient capacitance techniques : concentration, profiles and annealing temperature ranges have been determined. Irradiations at 6 K and 77 K give the same results : between 77 K and 300 K, four electron traps have been detected, identical to those observed after electron irradiation at 20 K. The two shallowest disappear after annealing at 100 K and 160 K respectively. One observed trap at least comes from a diffusion process before stabilization. Irradiation at room temperature gives similar results to an irradiation at 77 K followed by 300 K annealing.Les expériences ont été faites sur du matériau LEC non intentionnellement dopé. Les irradiations, avec des protons de 100 keV, sont effectuées aux températures 6 K, 77 K, 300 K et les pièges créés étudiés par méthodes capacitives : concentrations, profils et domaines de stabilités ont été déterminés. Les irradiations à 6 K et 77 K donnent les mêmes résultats expérimentaux. Quatre pièges principaux sont créés, identiques à ceux observés après irradiation aux électrons dans des conditions équivalentes. Il existe, de 77 K à 300 K, deux stades de recuit à 100 K et 160 K. L'un des centres au moins (A. 3) provient d'un processus complexe mettant en jeu une diffusion avant stabilisation. Une irradiation à 300 K est équivalente à une irradiation à 77 K suivie d'un recuit à 300 K

Effects of interface-layers composition and strain distribution on the optical transitions of InAs quantum dots on InP

International audienc

Detailed optical characterization of the deep cr level in gaas

The deep level optical spectroscopy by the so called DLOS technique gives the spectral shape of both σon(hv) and σ op(hv), the optical cross sections for the transitions between a deep level and the conduction and valence bands, in a very sensitive and selective way. We have applied this technique to the optical study of the HL1 trap related to chromium in GaAs, in very pure LPE layers of n and p type doped with chromium. We can therefore determine what kind of charge states of chromium we are dealing with by çomparing σo n and σop with the optical absorption spectra in bulk materials. Moreover, comparisons between the excitation spectra of luminescence and the photoionization cross section σo n and σop have given unambiguous interpretation of the origin of the two luminescence bands at 0.57 and 0.62 eV found by YAG laser excitation in bulk Cr doped GaAs depending on the Fermi level position. They are interpreted as the radiative transitions between the (Cr3+-Cr2+ ) centre and the bands. In this way, we give a coherent description of the thermal and optical properties of the single deep acceptor level corresponding to the Cr 3+ or Cr2+ states according to its electronic filling.Les caractéristiques optiques du niveau profond « HL1 » lié à la présence du chrome dans GaAs ont été étudiées par différentes méthodes pour donner une description précise du centre. Les sections efficaces d'ionisation optique σ on(hv) et σop(hν) ont été mesurées par spectroscopie capacitive optique (Deep Level Optical Spectroscopy — DLOS) sur GaAs LPE de type n et p dopé au chrome. Ces résultats permettent de déterminer l'état de charge du chrome dans un matériau massif par mesure d'absorption optique. L'origine des émissions à 0,57 et 0,62 eV liées au chrome est clairement démontrée par comparaison de leurs spectres d'excitation avec σon et σop. L'ensemble des résultats donne une description cohérente des propriétés thermiques et optiques du niveau correspondant aux deux états Cr+2-Cr+3