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International audience; A risk assessment for disasters is usually composed of hazard, vulnerability and exposure variables, which are hardly studied and modeled simultaneously. In volcanology, it remains ambitious to anticipate risk trajectories of pre- and post-eruption regimes. The interdependencies and feedback loops of the system's components, between geological, ecological, social and economic ones, give rise to trade-offs and synergies that should be disentangled for supporting decision-makers and helping local communities to face the risks. We developed here an innovative discrete-event and possibilistic model based on a dynamical network representation to assess volcanological multi-risk and long term post-eruption impacts of such a multifactorial system. We illustrated our method with the region around Mount Meru (Northern Tanzania), a strato-volcano with various eruption styles, located in a growing economic and touristic region (>1 M.inh.). We used qualitative and rule-based Petri nets, largely unused in environmental sciences, for an integrated assessment of the overall system dynamics and associated risks. As a central result, we showed that the region could recover from a blast eruption, irrespective of the timescale. Our study highlights the fact that agriculture and pastoralism remain key activities to favour the recovery of this region. Yet, as soon as subsidies from governmental and non-governmental organizations are lacking, the modeled region remains isolated from national and international activities and shifts to rural dynamics. Our case study can equip environmental risk assessment with innovative models, new dynamical indices (e.g. desirable and non-desirable trajectories), and rigorous reasoning for an ultimate integrated management of social-ecological systems at stake.

In this work, we present an advanced heterogeneous integration scheme which consists in integrating a thin InP layer by wafer-bonding onto a silicon wafer (InPoSi) on which a regrowth step of III-V materials is implemented. Vertical p-i-n AlGaInAs lasers obtained from a single Selective Area Growth (SAG) step on InPoSi were fabricated. Thanks to SAG, the AlGaInAs-MQW structures successfully cover a PL range of 160 nm in the C+L band. Based on these structures, a 5- channel laser array was fabricated. The latter successfully covers a 155 nm-wide spectral band from 1515 nm to 1670 nm with a maximum output power of 20 mW under continuous-wave regime at 20°C. High thermal stability up to 70°C is demonstrated with a characteristic temperature of 69°C for the lasers emitting from 1515 nm to 1600 nm.

International audience; We present a complete characterization of reflective electroabsorption modulators (EAMs) monolithically integrated with semiconductor optical amplifiers (SOAs), components that are capable of operating beyond 50 Gb/s in the C-band. The devices are based on GaInAsP multiple quantum wells on InP substrate, leveraging semi-insulating buried heterostructure waveguide definition and butt-joint integration technologies. Different device configurations, based on 80-μm and 150-μm long EAMs, are fabricated and characterized in both static and dynamic modes. The frequency response of the 80-μm long EAM is still flat at 26.5 GHz (setup upper limit) whereas the 150-μm long EAM exhibits a 3-dB cutoff bandwidth of 23 GHz. A zero-chirp is achieved for EAM reverse bias voltages between −1.2 V and −1.5 V depending on the wavelength. Under large-signal modulation, the frequency chirp induced by the shorter EAM is almost half that of the longer EAM, with their respective peak values being +1.5/−2 GHz and +3.2/−3.7 GHz (rising/falling edges) at 1545 nm (−1.3 V bias, 2.6 V voltage swing). We obtained high dynamic extinction ratios of ~14.5 dB and ~8 dB from the longer and the shorter EAMs, respectively, when they are operated at 25 Gb/s using non-return-to-zero coding. Finally, we achieved 12 km and 16 km colorless transmissions in the C-band (between 1530 nm and 1545 nm) over a standard single-mode fiber without equalization using the 150-μm and the 80-μm EAMs, respectively, with 4.5 dB and 2.5 dB dispersion penalties at a bit error rate of 10E−3.

International audience; We experimentally present a 10-Gb/s Fiber Wireless IFoF/V-band uplink of four625Mbaud 16QAM signals with a linear, high-power monolithically integrated reflective electroabsorptionmodulator with semiconductor optical amplifier for 5G mmWave fronthaul networks.

Vertical p-i-n lasers integrated by wafer-bonding and regrowth on a heterogeneous InP-on-SOI wafer are presented. We demonstrate for the first time lasers based on regrown III-V active regions efficiently coupled to Si-photonic DBR cavities.

Vertical p-i-n AlGaInAs lasers obtained from a single Selective Area Growth (SAG) step on a thin InP layer bonded to silicon wafers are presented. A PL extension from 1490 nm to 1645 nm was demonstrated on InP-SOI wafer. Based on this result, a record of 155 nm wide spectral range was obtained for FP lasers on InP-SiO 2 /Si wafer.

We demonstrate a hybrid silicon tunable laser with wide tunability and rapid switching speed for applications in sensing and optical networks. By implementing an optimized carrier injection phase shifter design, the filters of the silicon laser cavity may be efficiently controlled, enabling both fine and broad wavelength tuning across a 56 nm range, in addition to a rapid 10 ns switching time. The laser emits up to 10 dBm output power, and the linewidth is near 200 kHz. The fast wavelength switching demonstrated here may be employed in data center and access networks, while the potential for rapid wavelength sweeping is attractive for optical sensing and imaging applications.

We present a colorless transmitter based on a reflective electroabsorption modulator (EAM) monolithically integrated with a semiconductor optical amplifier (SOA). A semi-insulating buried heterostructure (SI-BH) technology is used to define the device waveguide structures. The integration of the SOA allows to fully compensate for insertion losses. We observe up to +2 dB net gain in the fiber-coupled output power, for 90 mA SOA bias current. We demonstrate 25 Gb/s operation with non-return-to-zero (NRZ) modulation format, with a dynamic extinction ratio (DER) up to 14 dB for 2.6 V peak-to-peak EAM driving voltage. Colorless operation is demonstrated over 15 nm spectral range in the C-band. We achieved 10 km dispersion limited transmission distance at 25 Gb/s NRZ with a penalty of 3 dB at 10−3 bit error rate (BER).

International audience

we present a 50 Gb/s O-band reflective electroabsorption modulator operating in both non-return-to-zero (NRZ) and PAM-4 modulation formats without equalization. We obtained >9 dB NRZ dynamic extinction ratio for a peak-to-peak voltage of 2.4 V.

Fabry-Perot laser arrays based on vertical p-i-n laser diode structures grown on InP layer directly bonded to Si wafer is presented. Lasing emission covering the C+L bands is achieved by means of a single-epitaxy Selective Area Growth (SAG) technology.

We demonstrate a 56-GBd pulse-amplitude modulation-4 compact InP transmitter module integrating a distributed feedback laser and an electro-absorption modulator, which exhibits 50-GHz bandwidth, >13-dB extinction ratio and up to 1.5-mW output power. Successful amplifier-free 112-Gb/s transmission is performed over 2 km using low complexity three-taps equalization. We also study the tradeoff between receiver bandwidth, equalizer length and performance, and show successful signal recovery with bandwidths as low as 18 GHz when increasing the equalizer length.

We present a 56Gbaud/s $13\mu{m}$ electro-absorption modulated laser, based on semi-insulated buried waveguide technology. A dynamic extinction ratio of 8.4dB, with 1. 8dBm fiber coupled average power, and 112Gb/s PAM4 transmission, with a $BER=10^{-3}$ , are demonstrated.

We demonstrate a SOA-UTC receiver PIC in O-band with up to 90 A/W responsivity, NF below 8-dB, >−10 dBm saturation input power and 33 GHz bandwidth which shows a 10−9 sensitivity at 32 Gb/s of −20.5 dBm.

We present a preamplified high-speed photoreceiver comprising a unitraveling carrier photodiode (UTC) monolithically integrated with a semiconductor optical amplifier (SOA). The SOA-UTC photoreceiver exhibits above 95-GHz 3-dB bandwidth, 8-dB noise figure, low polarization dependence loss of 1–2 dB and 95-A/W peak responsivity corresponding to record gain-bandwidth product of 6.1 THz.

We present an electro-absorption modulated laser with 6dBm modulated power leading to record power budget NRZ transmissions at 1.55μm: 37dB at 10Gb/s over 50km and 30dB at 28Gb/s over 10km with a pre-amplified photodiode.

A 112-Gb/s PAM4 transmitter module which integrates InP DFB and EAM demonstrated for the first time 2 km transmission with only 3-taps equalizer due to 50 GHz bandwidth, >13 dB extinction ratio and 1.5 mW output power.

We demonstrate a single polarization monolithically integrated coherent receiver on an InP substrate with a SOA preamplifier, a 90° optical hybrid, and four 40 GHz UTC photodiodes. Record performances with responsivity above 4 A/W with low imbalance

We present a pre-amplified high-speed photoreceiver comprising a uni-traveling carrier photodiode monolithically integrated with a semiconductor optical amplifier. The SOA-UTC exhibits 3-dB bandwidth of 95 GHz, NF(8 dB) and 95 A/W responsivity corresponding to record gain-bandwidth product of 6.1 THz.

The gridding irregularities of electron beam lithography may deterministically disorder photonic crystals (PhC). Their practical impact is addressed on a PhC wavelength selective device using a large grid size of 8 nm. The device operation, based on confined resonances and propagation mini-stopbands in a multimode waveguide, is deterministically blurred. Scattering length scales are correspondingly discussed. Strategies for higher throughput lithography are proposed accordingly

Access networks evolve towards longer reach, higher bit-rates and more subscribers per central office. This evolution could require flexible amplifiers such as Semiconductor Optical Amplifiers

We demonstrate that the combination of Quantum Dots and Quantum Dashes (QD) structures with buried ridge stripe technology allows to achieve QD semiconductor amplifier (SOA) with an internal gain of 30dB for an injected current of 350mA. Using optimized taper configuration, the beam divergence and the coupling losses are reduced down to 18°×22° and ∼3dB, respectively. It opens the way to an investigation of nonlinear properties and wavelength conversion scheme in high gain QD-SOA and to a fair comparison with SOA based on conventional bulk or multiple quantum wells material.

A new architecture for low-cost WDM-PON is proposed, which combines a multi-wavelength CW source with a Reflective SOA at 2.5 Gbps, with an optical budget up to 20 dB.

In this paper, we report on quantum dash based injection locked Fabry-Perot laser diode, which allowed us to demonstrate a 231−1 PRBS 10Gb/s coded signal over 20km SMF error-free transmission and over a spectral bandwidth more than 20nm.

Calculations show that electron states are not confined in the dashes in 1.55 mu m InAs/InP quantum dash-in-a-well laser structures. The combination of strain and three-dimensional confinement reduces the calculated density of states (DOS) near the valence band maximum, with the conduction and valence DOS then almost equal close to the band edges. Calculations and photoabsorption measurements show strongly polarized spontaneous emission and gain spectra. Experimental analysis shows the room temperature threshold current is dominated by nonradiative current paths. (C) 2008 American Institute of Physics. (DOI: 10.1063/1.2952194)

We report the successful growth of 9- and 12- layer InAs/InP Quantum Dash in-a-well (DWELL) laser structures using GSMBE. The performances of broad area (BA) lasers emitting at 1.55 µm are compared to those of devices made from 6-layer stacks. The impact of stacking on the modal gain and T 0 is investigated. The p-doping effect on the temperature stability is also discussed. Single ridge waveguide laser performance is finally reported.

This invited paper gives an overview of the recent advances on two-dimensional photonic crystals on InP based materials. In particular, the fabrication approach developed at Alcatel-Thales III-V Lab is described in detail. Optical characterisation of photonic crystal building blocks is presented. Results on functional optoelectronic devices, such as high power lasers, tunable lasers and wavelength monitor, integrating these building blocks, are summarized.

Single mode lasing of square lattice photonic crystal (PhC) waveguides is investigated experimentally and compared to simulation results. Lasing of a Wl PhC waveguide structure at 1.5 /spl mu/m on InP substrate is reported for the first time.

Summary form only given. Here, a detailed investigation of the cascadability of gain clamped semiconductor optical amplifiers (GC-SOAs) is presented and compared to that of conventional SOAs for different bit rates. The analysis is both theoretical and experimental and shows that at 2.5 Gbit/s more than 30 GC-SOAs can be cascaded while only seven conventional SOAs (@1-dB penalty).

SOA-based devices provide a family of key components for optical networks, including wavelength conversion, regeneration, space switching and wavelength selection. All these functions require integration of multiple SOAs that calls for efficient combination of monolithic and hybrid integration to reach performances and cost effective solutions. Several examples are presented and discussed.

International audience; A quantum dash Fabry-Perot actively modelocked laser module is tested as part of a 42.7 Gbit/s transmitter with more than 10 nm wavelength tunability. Its low chirp level is also assessed through chromatic dispersion tolerance measurements.