H. Folliot

Achievement of High Density InAs Quantum Dots on InP (311)B Substrate Emitting at 1.55 µm

The As flux effect on InAs quantum dots formed by gas source molecular beam epitaxy on InP substrates, oriented following the (311)B crystallographic direction has been studied. Atomic force microscopy images show that the quantum dot (QD) density dramatically increases and quantum dot sizes decrease, when decreasing the As pressure. Moreover, the size dispersion is narrowed. Photoluminescence measurements on the high QD density samples is shifted to higher energy, toward the telecommunication important 1.55 µm emission.

Room temperature photoluminescence of high density (In,Ga)As/GaP quantum dots

We report on the achievement of high density (In,Ga)As self-assembled quantum dots on GaP substrate with a good homogeneity. Good structural and electronic properties have been achieved, as revealed by room temperature photoluminescence measurements and by comparison to both InAs/GaAs and InAs/InP materials reference systems. This is supported by atomistic calculations where the indium incorporation in InGaAs/GaP quantum structures is found to enhance both the type-I bandlineup and direct bandgap properties. The photoluminescence temperature dependence of the bandgap evidences the quantum confinement effects. Our results provide a valid framework to implement silicon optical devices based on InGaAs/GaP nanostructures.

Si wafer bonded of a‐Si∕a‐SiNx distributed Bragg reflectors for 1.55‐μm-wavelength vertical cavity surface emitting lasers

Amorphous silicon (a-Si) and amorphous silicon nitride (a-SiNx) layers deposited by magnetron sputtering have been analyzed in order to determine their optical and surface properties. A large value of ~1.9 of index difference is found between these materials. Distributed Bragg reflectors (DBR) based on these dielectric materials quarter wave layers have been studied by optical measurements and confronted to theoretical calculations based on the transfer matrix method. A good agreement has been obtained between the experimental and expected reflectivity. A maximum reflectivity of 99.5% at 1.55 µm and a large spectral bandwidth of 800 nm are reached with only four and a half periods of a-Si/a-SiNx. No variation of the DBR reflectivity has been observed with the time nor when annealed above 240°C and stored during few months. This result allows to use this DBR in a metallic bonding process to realize a vertical cavity surface emitting laser (VCSEL) with two dielectric a-Si/a-SiNx DBR. This bonding method using AuIn2 as the bonding medium and Si substrate can be performed at a low temperature of 240°C without damaging the optical properties of the microcavity. The active region used for this VCSEL is based on lattice-matched InGaAs/InGaAsP quantum wells and a laser emission has been obtained at room-temperature on an optically pumped device.

Growth and optical characterizations of InAs quantum dots on InP substrate: towards a 1.55 /spl mu/m quantum dot laser

In recent years, self assembled quantum dots (QDs) have attracted much attention, because of the great potentialities expected from their zero dimensional confinement properties, especially for the realization of opto-electronic devices such as lasers. Indeed, for a QD based laser, a lower temperature dependence (high T/sub 0/), a lower chirp (/spl alpha//sub H/) and a higher modulation bandwidth are predicted compared to the conventional quantum well lasers. Numerous studies have been performed for the growth of InAs/GaAs QDs, and lasers have been realized, presenting improved performances (T/sub 0/=161 K @ 350 K [1], /spl alpha//sub H/=0 @ 1 GHz [2]).

Guided Photoluminescence from Integrated Carbon-Nanotube-Based Optical Waveguides

Thin films and ridge waveguides based on large-diameter semiconducting single-wall carbon nanotubes (s-SWCNTs) dispersed in a polyfluorene derivative are fabricated and optically characterized. Ridge waveguides are designed with appropriate dimensions for single-mode propagation at 1550 nm. Using multimode ridge waveguides, guided s-SWCNT photoluminescence is demonstrated for the first time in the near-infrared telecommunications window.

Coherent integration of photonics on silicon through the growth of nanostructures on GaP/Si

Selected results obtained in the framework of MBE grown nanostructure for photonics on silicon are repsented in this paper. We present first a comprehensive study of GaAsPN/GaPN quantum wells (QWs) grown onto GaP substrates, in the light of a comparison with their N-free GaAsP/GaP QWs counterpart system. High density of small InGaAs/GaP Quantum Dots are presented next with their PL properties. Finally, RT photoluminescence properties of GaAsPN/GaPN QWs onto Si substrate are presented and discussed in term of carrier injection efficiency. However, for future development, optical properties of the active area must be improved and are tightly bound to the structural perfection of the GaP/Si template layer. To address this point, structural analyses including X-Ray Diffraction (lab setup and synchrotron) and Transmission Electron Microscopy have been performed, with a particular care for typical III-V/Si defect characterisation. First results of Si buffer layer growth are also presented as a perspective for future low defect MBE grown GaP/Si template layers.

Enhancement of VCSEL Performances Using Localized Copper Bonding Through Silicon Vias

We report on a new cost effective, with a low temperature budget and simple bonding process on silicon, presenting efficient heat spreading and great potentialities in integration. This process is based on a thick electro-plated copper bonding layer through silicon vias and is expected to reduce significantly the bonded device internal temperature. We apply this process to realize 1.55-<inline-formula> <tex-math notation=LaTeX>

Class-A operation of an optically-pumped 1.6 µm-emitting quantum dash-based vertical-external-cavity surface-emitting laser on InP

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EFFECTS OF INTERFACE-LAYERS COMPOSITION AND STRAIN DISTRIBUTION ON THE OPTICAL TRANSITIONS OF INAS QUANTUM DOTS ON INP

</tex-math></inline-formula> emitting vertical-cavity surface-emitting lasers. We demonstrate continuous wave operation from room temperature up to 55 °C, an internal temperature reduction of 13 °C, and we estimate a decrease of 30% of the overall device thermal impedance.

wavelength vertical cavity surface emitting lasers.

A continuous-wave 1.6 µm-emitting InAs Quantum Dash-based Optically-Pumped Vertical-External-Cavity Surface-Emitting Laser on InP is demonstrated. The laser emits in the L-band with a stable linear polarization. Up to 163 mW output power has been obtained in multi-transverse mode regime. Single-frequency regime is achieved in the 1609-1622 nm range, with an estimated linewidth of 22 kHz in a 49 mm cavity, and a maximum emitted power of 7.9 mW at 1611 nm. In such conditions, the laser exhibits a Class-A behavior, with a cut-off frequency of 800 kHz and a shot-noise floor of -158 dB/Hz for 2 mA of detected photocurrent.