Characterization of InAs quantum wires on (001) InP: toward the realization of VCSEL structures with a stabilized polarization

International audienceVertical cavity surface emitting lasers (VCSELs) operating at 1.55-µm are of great interests in optical telecommunication applications. Their circular, spectral and spatial single mode laser beam is essential points for an efficient fiber coupling and high frequency modulation. Moreover, their low-cost production and the possibility to test each laser directly on the wafer represent great advantages for production applications. In contrast with edge emitting lasers, VCSEL present an important polarization instability, which may increase the bit error rate in data transmission. Different solutions have been proposed for controlling the polarization, from patterning the output mirror or by using a birefringent material on top of the mirror, which do complicate the device technology. In this contribution, we propose to use a gain material presenting an important polarization anisotropy like quantum wires in order to fix the polarization of the emitting VCSEL

InAs quantum wires on InP substrate for VCSEL applications

International audienceQuantum dash based vertical cavity surface emitting lasers (VCSEL) on InP substrate are presented. Single and close stacking layers were successfully grown with molecular beam epitaxy. Optimized quantum dash layers exhibit a strong polarized 1.55 µm photoluminescence along the [1-10] crystallographic axis. Continuous wave laser emission is demonstrated at room temperature for the first time on a quantum dash VCSEL structure on InP susbtrate. The quantum dash VCSEL laser polarization appears stable on the whole sample and with excitation, no switching is observed. Its polarization is mainly oriented along [1-10], an extinction coefficient of 30 dB is measured. Those preliminary results demonstrate the interests of quantum dashes in the realization of controlled and stable polarization VCSEL device

PHOTOCURENT SPECTROSCOPY OF InAs/GaInAsP(Q1.18) QUANTUM DOTS

We present photocurrent measurements of InAs/InGaAsP (Q1.18) quantum dots embedded in a PIN diode grown on InP(311)B substrates. From the room temperature spectrum we deduce the fundamental E0 = 0.8eV and first excited E1 = 0.83eV energy levels of the dots. These energy levels are consistent with photoluminescence (PL) spectroscopy measurements E0=0.82eV. They are in good agreement with numerical simulations. Liquid nitrogen temperature measurements give E0=0.84eV and E1=0.895eV in agreement with PL measurements. Electroluminescence study correlates these results. Absorption coefficient was extracted from PC

Self-organized growth of InAs quantum dots on InP(001)

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Optical properties and morphology of the quantum dots InAs/InP (311)B characterized by photoluminescence

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Achievement of High Density InAs/GaInAsP Quantum Dots on Misoriented InP(001) Substrates Emitting at 1.55 μm

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Evidence of lateral coupling on the carrier dynamics in InAs/InP(311)B quantum dots

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Negative characteristic temperature of long wavelength InAs/AlGaInAs quantum dot lasers grown on InP substrates

International audienceInAs quantum dot lasers grown on (311)B InP substrates with AlGaInAs barriers have been fabricated and studied. A large decrease of the threshold current with temperature was observed from 110 to 140 K. In the same temperature range, electroluminescence spectra showed a shape change, an energy shift with temperature, which cannot be fitted with a Varshni law, and a large decrease of the laser linewidth. These results can be related to a delayed thermalisation of carriers within quantum dot ensemble

Polarization control of 1.6 µm vertical-cavity surface-emitting lasers using InAs quantum dashes on InP(001)

International audienceThe authors report the demonstration of a polarization-controlled vertical-cavity surface-emitting laser (VCSEL), emitting at the telecommunication wavelength. VCSELs are based on an active medium constituted of well elongated InAs quantum dashes (QDHs) nanostructures grown on conventional (001) oriented InP substrate. QDHs present important optical polarization anisotropies according to the (1-10) crystallographic orientation. Inserted into a VCSEL microcavity, QDH VCSELs show a continuous wave laser operation at 1.6 µm, at room temperature, with a reduced 13 kW/cm2 optical excitation density threshold. The QDH VCSEL output laser polarization is fixed along the same (1-10) direction. Power and temperature dependant measurements do not show any polarization instabilities and switching on all QDH VCSELs. A polarization extinction ratio as high as 30 dB is deduced from experiments