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Dans ce travail, un absorbant saturable est utilisé pour améliorer le taux d'extinction d'un train d'impulsions picosecondes cadencé à 160-GHz et centré sur 1555 nm. Une amélioration du taux d'extinction de 6 dB est observée sur une plage de longueur d'onde de 8 nm.

Thanks to the high transmission coefficient of short infrared wavelengths in the atmosphere and specific contrasts, SWIR imaging is an attractive technology for space applications such as astronomical or earth observation. Detection module must demonstrate high uniformity, sensitivity and resolution combined with compactness to meet the needs of this application field. Image sensors based on InGaAs photodiodes arrays present very low dark currents even at ambient temperature as high quality materials can be grown on InP substrates. Besides, the suppression of InP substrate after hybridization is a way to extend the detection range towards visible wavelengths. These properties result in a new generation of sensitive, compact and multifunctional InGaAs detection modules. In this paper, we describe the performances of an uncooled VGA InGaAs module recently developed. The 640x512 array with a pitch of 15m allows high resolution images. The excellent crystalline quality induces very low dark current densities at ambient temperature. The readout circuit is based on a capacitive trans-impedance amplifier with correlated double sampling resulting in low readout noise figure. This compact module appears as a serious alternative to the existing technologies for low light level imaging in the [0.4m-1.7m] spectral range.

Dans ce travail, un absorbant saturable est utilis? pour am?liorer le taux d'extinction d'un train d'impulsions picosecondes cadenc? ? 160-GHz et centr? sur 1555?nm. Une am?lioration du taux d'extinction de 6?dB est observ?e sur une plage de longueur d'onde de 8?nm.

A vertical-access passive all-optical gate has been used to improve the extinction ratio of a 160 GHz picosecond pulse train at 1555 nm. An extinction ratio enhancement of 6 dB is observed within an 8 nm bandwidth. Such a device is a promising candidate for low-cost all optical reamplication and reshaping (2R) regeneration at 160 Gbits/s.

A coplanar distributed amplifier, fabricated in a double channel InP HEMT technology, is presented. It exhibits a 13 4;dB gain and a 92 4;GHz −3 4;dB cutoff frequency that corresponds to a gain-bandwidth product of 410 4;GHz. Key aspects for distributed and coplanar design around 100 4;GHz are highlighted.

Evanescently coupled photodiodes have been designed for hybridisation on an Si platform. Diluted multimode waveguides have been optimised with a genetic algorithm. High efficiency photodiodes at both 1.3 and 1.5 µm, with very low polarisation dependence, have been fabricated with low bias, 2.5 Gbit/s capability and high reliability.

50 GHz bandwidth photodiodes, attaining a compression point of +12 dBm, have been fabricated. The structure design allows an almost complete absorption at 25 µm, corresponding to 0.5 A/W responsivity and gives a polarisation dependence as low as ±0.1 dB. These components have been realised with a low-cost technology including etched waveguide input facet, antireflection coating on wafer and cleaving V-grooves.

A performance comparison of InGaAs/GaAs and InGaNAs/GaAs strained quantum well (QW) laser structures grown by MOVPE is presented. Infinite threshold current densities of 0.095 and 1.22 kA/cm2, with slope efficiencies of 0.25 and 0.15 W/A at emission wavelengths of 1.18 and 1.22 µm, were obtained, respectively. A characteristic temperature (T0) of 80 K was determined for as-cleaved InGaAs QW lasers, while a T0 value as high as 117 K was obtained for InGaNAs QW lasers in the 20–80°C temperature range.

Long wavelength bulk InGaAsN semiconductor laser structures have been grown on GaAs substrate by AP-MOVPE, using DMHY and TBAs. After thermal annealing, GaAs/InGaAsN, and AlGaAs/InGaAsN Fabry-Perot laser diodes were processed from the wafers. At room temperature, stimulated emission was observed at peak wavelength from 1.15 to 1.38 µm, and laser operation was achieved at 1.16 and 1.275 µm. Infinite current density is extrapolated to 12 kA/cm2 for AlGaAs/InGaAsN bulk laser diodes.

Mode-locked vertical-extended-cavity-surface emitting lasers (ML-VECSEL) are promising candidates for the generation of stable short pulses at multi-GHz rate. However, the poor thermal behavior of quaternary InP-based semiconductor compounds often limits the performance of ML-VECSELs operating at 1.55 m. In this work, we report on a specific approach using downward heat sinking to optimize the heat dissipation out of the active region. VECSEL chips with a low thermal resistance are fabricated using a hybrid metal-metamorphic GaAs/AlAs mirror and bonding to a highly thermally conductive host substrate. We show that superior performance can be obtained with a CVD diamond substrate, while electroplated copper host substrate can afford a flexible and low cost alternate approach for moderate (~100 mW) output power. The VECSEL chip assembled with a 1.55m fast InGaAs(Sb)N/GaAsN semiconductor saturable absorber mirror (SESAM) produces nearly Fourier transform-limited mode-locked pulses at ~ 2 GHz repetition frequency, and the RF linewidth of the free running laser is measured to be less than 1000 Hz. When the resonance and group delay dispersion of the SESAM microcavity are tuned by selective etching of specific top phase layers, the modelocked pulse width is reduced from several picoseconds to less than 1 ps.

SWIR image sensors based on p-i-n photodiodes arrays present a tremendous interest in applications often requiring a high intra-scene dynamics. This paper describes a single-chip InGaAs SWIR camera with more than 120 dB intrinsic operational dynamic range with an innovative CMOS ROIC technology initially developed by New Imaging Technologies for visible CMOS camera chip. A simplified camera with on chip fixed pattern noise correction is presented. We also present the next generation of focal plane arrays (FPA) based on a VGA format of 640 x 512 pixels with a pitch of 15 m. These FPAs are associated to a logarithmic wide dynamic range ROIC. We give the electro-optics performances and particularly the visible extension capabilities. This InGaAs VGA logarithmic single-chip camera allows a high resolution SWIR camera with minimized system complexity and low power consumption.