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We report, for the first time, a transmission experiment over standard fiber at 1.55 μ m using an electroabsorption modulated laser (EML) integrated with a semiconductor optical amplifier (SOA). We show clearly that negative pre-chirped signals can be obtained by adjusting both modulator and amplifier driving parameters. Negative chirp operation is evaluated through small-signal chirp measurement as well as through time-resolved dynamic chirp measurement. Signal chirp control at emission enhances transmission and increases optical reach. Thanks to the SOA gain and chirp compensation for modulator loss and chirp, dispersion-penalty-free with clear open eye diagrams over 100 km of optical fiber at 10.3 Gb/s is achieved. A transmission up to 125 km is also obtained. This novel fully integrated EML-SOA is very promising as a high-performance, compact and low-cost optical transmitter for the future access-metropolitan network convergence.

A performance comparison of single- and two-section reflective semiconductor optical amplifiers (RSOAs), used as remote modulators for the transport of IEEE 802.11n type signals at 0.3 GHz is reported. The two-section RSOA yields higher link gain and lower output noise than the single-section RSOA while retaining high output power. It provides a wide operational dynamic range and high tolerable path loss.

Quantum dash lasers were irradiated for the first time, using 31-MeV protons. These novel structures, which show promising performances for 1.55 mum optical communications exhibit better robustness to radiation than quantum well lasers.

We fabricate tunable semiconductor lasers with two coupled photonic crystal cavities that allow up to 46 nm tuning range with a side-mode suppression ratio greater than 30 dB. The effect of design parameters on device performances is discussed. In particular, we demonstrate that the lattice parameter of photonic crystals and the dimensions of the coupled cavities are the key parameters. On the basis of tuning curves, we also explain the tuning mechanisms and the guidelines for improving laser performance. Finally, we present a laser that enables tuning on three coarse wavelength dense multiplexing (WDM) channels.

Thickness and composition profiles of AlGaInAs-based layers grown by low-pressure metal organic vapour phase epitaxy in the regime of selective area growth (SAG) have been modelled and measured experimentally. Experimental thickness profiles of InP, GaAs and GaAlAs bulk layers grown in the SAG regime have been precisely fitted with a three-dimensional vapour phase-diffusion model, and the characteristic diffusion length coefficient (D/k) for In, Ga and Al extracted. The D/k diffusion parameter for aluminium has been calculated and found intermediate between the indium and gallium ones. The diffusion model predict both thickness and compositional variations of AlGaInAs layers selectively grown for different mask patterns. The excellent agreement obtained between calculated and measured profiles makes this modelling tool essential for engineering of future SAG integrated optical devices.

Lasing of triangular and square lattice photonic crystal, waveguides on InP substrate is investigated around the 1.5-/spl mu/m wavelength by optical pumping. The lattice period of the fabricated structures is varied over a very large scale, thereby allowing a detailed exploration of the laser behaviors in the cases of micrometer width waveguides. A genuine distributed feedback (DFB) laser emission is observed in the gap for W2-3 waveguides in the /spl Gamma/M direction of a triangular lattice. A different behavior is obtained for W3 waveguides in the /spl Gamma/K direction of the same lattice as well as for W1 and W3 waveguides in the /spl Gamma/X direction of a square lattice. The laser emission is found to occur at the /spl Gamma/ point of the Brillouin zone (wavevector k=0) when the emission frequency is outside the gap. The DFB-like laser emission is intrinsically single mode in this case. Plane wave calculations show that the field distributions of the two DFB components are radically different. The emitting mode is well localized in the guide core while the non-lasing mode spreads over the whole crystal.

We report on a heterogeneously integrated InP/silicon-on-insulator (SOI) laser source realized through divinylsiloxane-bis-benzocyclobutene (DVS-BCB) wafer bonding. The hybrid lasers present several new features. The III-V waveguide has a width of only 1.7 mu m, reducing the power consumption of the device. The silicon waveguide thickness is 400 nm, compatible with high-performance modulator designs and allowing efficient coupling to a standard 220-nm high index contrast silicon waveguide layer. In order to make the mode coupling efficient, both the III-V waveguide and silicon waveguide are tapered, with a tip width for the III-V waveguide of around 800 nm. These new features lead to good laser performance: a lasing threshold as low as 30 mA and an output power of more than 4 mW at room temperature in continuous-wave operation regime. Continuous wave lasing up to 70 degrees C is obtained.

We demonstrate that the use of an optimized bi-electrode reflective semiconductor optical amplifier as remote modulator reduces the chirp. Our simulation shows that the chirp reduction is due to the carrier density profile in multi-electrode reflective semiconductor optical amplifiers. As a result of the chirp reduction, penalties for transmission are reduced from 6 to 4.5 dB on standard fiber at 2.5 Gb/s over 50 km. Using tri-electrode devices, a penalty of 3 dB is obtained for the same transmission conditions.

The modulation bandwidth has been identified as a specific limitation of quantum-dot or quantum-dash (QDash) lasers for direct modulation application. Solutions using tunnel injection and p-doping have already been demonstrated to increase the modulation bandwidth above 10 GHz, but with complex tunnel injection design and p-doping induced high internal losses. We show in this letter that the use of optimized QDashes and waveguide structure is sufficient to reach such high bandwidth at 1.55 mum. The device is validated by a large signal modulation demonstration at 10 Gb/s.

Self-organized InAs quantum-dot (QD) lasers emitting at 1.5 /spl mu/m were grown by gas source molecular beam epitaxy on (100) InP substrates. Room temperature continuous-wave (CW) operation of QD-based buried ridge stripe lasers is reported. We investigated experimentally the relevant CW performances of as-cleaved InP-based QD lasers for telecom applications such as temperature properties (T/sub 0/=56 K), infinite length threshold current density (J/sub /spl infin///spl sim/150 A/cm/sup 2/ per QDs layer) and internal efficiency (0.37 W/A). Lasing in pulsed mode is observed for cavity length as short as 200 /spl mu/m with a threshold current of about 37 mA, demonstrating the high gain of the QD's active core. In addition, the Henry parameter of these InP-based QD lasers is experimentally determined using the Hakki-Paoli method (/spl alpha//sub H//spl sim/2.2).

A hybrid III-V on silicon laser, integrating two intra-cavity ring resonators, is fabricated by using a wafer bonding technique. It achieves a thermal tuning range of 45 nm, with side mode suppression ratio higher than 40 dB.

International audience; Highly compact dual-mode semiconductor laser sources get more and more attention in different application fields such as radar, security and personal communication systems. When the two generated wavelengths are detected within the same photodetector, an electrical signal which frequency is the difference between the frequencies of the two optical modes will be issued. We report on an integrated semiconductor device which is composed of two in-line DFB sections that are using the same optical waveguide structure. The so generated dual-mode spectrum can be adjusted first, by the difference in the grating parameters of each DFB section and second, by their respective driving current. We will report on the characterisation of such a device focusing on tunability and linewidth aspects that are of prime importance in above mentioned applications.

Buried ridge stripe lasers have been grown on InP in two steps by gas source molecular beam epitaxy. The active structure consists of a compressively strained layer multi quantum well with an equivalent wavelength emission at 1.5 μm. The stripe was defined by reactive ion etching. A threshold current of 22 mA was reproducibly obtained on a laser length of 500 μm. A CW output power of 48 mW per facet was achieved. In addition, preliminary accelerated aging tests have shown the high reliability of the structure.

We demonstrate that the use of an optimized (high gain) bi-electrode reflective semiconductor optical amplifier as remote modulator enables 100 km transmission on single mode fiber below the FEC limit at 2.5 Gbit/s for colourless operation.

Different structures for optoelectronic devices have been grown by gas source molecular beam epitaxy. Strained layer multiquantum well structures with quarternary wells exhibit low threshold current density (Jth=510 A/cm2) and high T0 value (90 K). A two step growth procedure enables the realization of the vertical structure distributed feedback laser with very good control of the coupling coefficient between laser mode and engraved gratings. Finally, the realization of a buried heterojunction laser is demonstrated in a three-step epitaxial process and a new lift-off procedure avoiding the use of a dielectric mask. Preliminary devices show power emission up to 40 mW with a threshold current Ith=60 mA.

In this communication, we report experimental results on optical injection of quantum dot (Q-dot) [1] and quantum dash (Q-dash) [2] semiconductor multi-mode lasers. We show the impact of a strong damping on optical injection map and reveal the observation of a random phenomenon of multi-excitability on such structure. These properties are obtained thanks to the different structural properties of Q-dash and Q-dot and by comparing Q-dash lasers having different numbers of Q-dash plans.

Calculations show electrons are not confined in the dashes in 1.5 mum InAs/InGaAsP/InP quantum dash in a well structures. Calculations and photoabsorption measurements show strongly polarised recombination. The threshold current remains dominated by Auger recombination.

We study modulation properties of state-of-the-art quantum dot lasers and compare them with state-of-the-art Al-based quantum well lasers. In particular, we demonstrate uncooled transmission over 20 km at 10 Gbit/s, limited by a large adiabatic chirp.

We demonstrate ~590 fs pulse generation at a 245 GHz repetition rate using a one-section Fabry-Perot quantum-dash-based laser. A time-bandwidth product of 0.41 and average output power in excess of 20 mW are achieved.

A selective area growth model was used to engineer a remote amplified modulator with an AlGaInAs multi-quantum well active layer. The selective mask layout was designed to fulfill special component requirements including +35 nm SOA gap detuning and low polarization dependence. The fabricated reflective device exhibits 10 dB maximum insertion gain and operates at 10 Gbit/s over 80 nm spectral range.

We study 1.5 mum quantum ldquodash in a wellrdquo (DWELL) and quantum ldquodash in a barrierrdquo (DBAR) lasers. Calculations for the DWELL show a similar magnitude can be achieved for the conduction and valence band density of states over a sizeable energy range, the optimum case for a semiconductor laser. Experimental characterisation shows the room temperature threshold current remains dominated by non-radiative recombination, as previously observed for 1.55 mum quantum well lasers.

A modulation bandwidth up to 10 GHz in continuous wave mode operation is demonstrated using optimized 1.55 mum InAs/InP (100) quantum dashes based lasers.

International audience; The comparison of relative intensity noise (Rin) shows improved performances, for quantum dash laser (QD) compared to the ones of bulk medium structures. We introduced a statistical measurement through a coupling parameter that reveals the impact of strong damping on the competition between modes or the so-called partition noise. The existence of a strong damping in QD laser prevents the relaxation frequency from being observed in the coupling parameter, which makes the noise to appear as if the laser lines were inhomogeneous. However the method also enables the characterization of the coupling strength between modes, showing again differences between QD and bulk structures.

We report on the recent advances in InP-based Quantum Dashes (Qdashes) material for 1.55μm optoelectronic devices. We achieve highly uniform, reproducible and wavelength-controlled Qdashes, with a length ranging from 50nm to 500nm depending on the growth conditions. These Qdashes lead either to high modal gain distributed feedback (DFB) lasers or low chirp semiconductor optical amplifier (SOA). Moreover, we demonstrate that Qdashes are compatible with buried ridge stripe and shallow ridge technology and lead to very reliable lasers. Directly modulated lasers with 10GHz bandwidth are demonstrated in continuous wave mode operation. 10Gb/s transmission over 25km in semi-cooled operation is achieved using DFB buried lasers. Qdashes optimization leads to SOA with internal gain of 10 dB and a -3dB optical bandwidth of 120 nm at 50°C, paving the way for semi-cooled CWDM optical sources. Furthermore, low chirp Qdashes SOA are evaluated as optical boosters after a modulated source. Although we still observe overshoots on the amplified signal, the chirp, even in their saturation regime, is low enough to allow for 50 km of transmission at 10Gb/s.

Electrical spectrum line-width is reduced in mode-locked FP 1.55 μm-QD laser diode through optical confinement factor optimization. From optimized structures, we obtained nearly Fourier-transform limited pulses at 10 GHz, with an averaged width of 8 ps over 10 nm.

Polarisation insensitive injection locking of two-section Fabry-Perot laser diodes is demonstrated, allowing to achieve error free transmission through 50 km over 20 nm at 2.5 Gb/s.

We studied selective area growth modeling and characterization of the AlGaInAs material system. We used a three-dimensional vapor phase diffusion model to extract the effective diffusion lengths of Al, Ga, and In species from measured thickness profiles of the three binaries AlAs, GaAs, and InP. Our growth conditions yield to 50, 85, and 10 μm for Al, Ga, and In, respectively. Based on these values, we achieved a precise prediction of AlGaInAs thickness, composition, band gap, and biaxial strain variations in different selective area growth conditions. Particular attention was paid to the influence of neighboring cells in the case of high mask density. This configuration occurs in practical component mask layout. High mask density leads to interferences between masked cells and enhances the effect of the long diffusion length of aluminum and gallium species. Then, the biaxial strain is tensile shifted and the band gap is blue shifted in the vicinity of a mask, compared to reference material features grown...

This paper summarizes recent advances on InAs/InP mode-locked quantum dashes (QD) lasers, and their applications for all-optical clock recovery, short pulse generation and millimeter wave generation. We demonstrate that QD FP lasers, owing to the small confinement factor and the 3D quantification of electronic energy levels, exhibit a beating linewidth as narrow as 15 kHz. Such an extremely narrow linewidth, compared to their QW or bulk counterparts, leads to the excellent phase noise and time jitter characteristics when QD lasers are actively mode-locked. We report also on an actively mode-locking tunnel injection quantum dash Fabry-Perot laser diode at 42.7GHz, generating nearly Fourier transform limited pulses with a pulse width of 2ps over 16nm.

Quantum dash lasers were irradiated for the first time, using 31 MeV protons. These novel structures, which show promising performances for 1.55 mum optical communications exhibit better robustness to radiation than quantum well lasers.

We investigate in detail the influence of the tunneling-injection design on the device performances of InAs/InP QDashes-based broad-area lasers. Using optimum design, high-performances single mode buried ridge stripe Fabry-Perrot lasers are reported (external efficiency of ~0.17 W/A per facet and threshold current of ~16 mA for as-cleaved 600 mum-long cavity). A relaxation frequency of 8.5 GHz is reported, indicating the good potential of such design for 10 Gb/s direct modulation, and the actual limitations of small-signal modulation bandwidth are discussed.

Thicknesses and compositions of AlGaInAs-based layers grown by low-pressure metal-organic vapor-phase epitaxy (LP-MOVPE) in the regime of selective area growth (SAG) have been measured and calculated. In this study, we have grown InAs, GaAs and AlAs binary bulk layers on patterned InAs and GaAs substrates, respectively, in order to assess separately the vapor-phase diffusion (VPD) length (D/k) of indium, gallium and aluminum species. Special care has been taken in the evaluation of the Aluminum D/k ratio, on which little information was available. A 3D VPD model has been used to predict the composition and thickness profiles of various alloys. The calculated profiles have been compared to the experimental ones for GaInAs, AlInAs, AlGaInAs layers and GaAlAs layers deposited on patterned InP and GaAs substrates, respectively. The good agreement between modeling and experiment, together with the perfect selectivity obtained for all the different alloys, holds for the validity of the calculated D/k ratio of Al, Ga and In species. In MOVPE-SAG, the efficiency of a computational model is a key issue for the engineering of future SAG integrated optical devices.

Quantum dot material offers new perspectives for the development of low-cost, high performing semiconductor laser and amplifiers. The 3D quantification of the energy levels in quantum dots leads to potentially high optical gain and efficiency, and thus the possibility of operation at lower currents than quantum well devices. Better resistance to temperature change, lower linewidth enhancement factor and lower noise are also expected. The elaboration and the basic properties of the quantum dot material for laser and amplifiers will be first presented. Then the main device performance will be detailed, as well as the disruptive properties already obtained. Potentials for microwave photonic applications will be discussed.

Bulk active region DBR lasers emitting at 1.55 ?m with no absorbing section have been evaluated as optical source for microwave signal generation. These devices self pulsate at 34 GHz with a linewidth of about 150 kHz, making it suitable for low jitter signal generation. Both electrical and optical active mode-locking were successfully obtained with this component opening the field of this device to microwave carrier distribution and regeneration.

Monolithic quantum dot Fabry-Perot laser diodes are fabricated and characterized for ultra-stable clock signal generation. Pulse width of 7ps and electrical line-width as narrow as 2 kHz are obtained.

It had been demonstrated that a two-gain-section bulk active layer Fabry-Perot semiconductor laser allows sub-picosecond pulse generation for a wide range of bias conditions, with the shortest pulse width of 650 fs at 41 GHz.

Buried ridge distributed feedback lasers operating at 1.55 μm wavelength range are fabricated based on dashes-in-the-well InAs/InP. The first floor free 10 Gb/s direct modulation is demonstrated for back-to-back and an accumulated dispersion of 100 ps/nm.

We investigate the devices performances of InAs/InP (100) quantum dash buried stripe ridge lasers. We demonstrate high-gain quantum dash based lasers whose dynamic properties are compatible with high-speed devices requirements. The good temperature characteristic of such lasers allows 10 Gb/s direct modulation in the temperature range of 25-75/spl deg/C. The mode-beating RF spectrum of passively locked FP quantum dashes laser shows a very narrow spectral linewidth (50 kHz) attributed to a strong phase correlation between modes.

We demonstrate tunable semiconductor lasers based on three coupled photonic crystal cavities, that allows up to 18 nm tuning range with a side-mode suppression ratio greater than 3.5 dB, in two different wavelength ranges

We demonstrate tunable semiconductor lasers based on three coupled photonic crystal sections, that allows up to 18 nm tuning range with a side-mode suppression ratio greater than 35 dB.

A new tensile strained material system, GaInNAs/InP, has been developed in order to achieve TM lasing around 1.55 mum, for further isolator integration. First static and dynamic evaluation of such GaInNAs/InP multi-quantum-well lasers is reported.

Monolithic and mono-section InAs/InP quantum dot Fabry-Perot laser diodes are fabricated and characterized in an actively mode-locked mode for ultra-stable clock signal generation. Electrical line-width as narrow as the 10 Hz detection resolution is obtained

Fabrication of InAs QDs grown on (100) InP substrate by GSMBE is reported. We investigate the room temperature operation of QDs-based broad area and buried ridge stripe lasers emitting at 1.5 /spl mu/m (J/sub Th/, T/sub 0/, /spl alpha//sub H/).

Buried ridge hetero-structure with p-n blocking layers semiconductor optical amplifiers have been designed and fabricated. Noise figure as low as 6.5 dB has been obtained in the case of low spatial hole burning, by optimising the confinement factor.

Both passive and active mode-locking have been demonstrated in single-section quantum dots Fabry-Perot semiconductor lasers without saturable absorber, generating pulses at 28 GHz repetition frequency with one picosecond pulse width. (2 pages)

10 Gb/s operation at 1.55 μm of an InAs/InP (001) dots-in-a-well buried ridge stripe Fabry-Perot laser is demonstrated for the first time, in the temperature range 25-75°C. (2 pages)

40 GHz self-pulsating distributed Bragg reflector lasers with a polarization insensitive bulk active layer of 0.7/spl times/0.5 /spl mu/m/sup 2/ showed enhanced non-linear behavior at low power level, and nearly 1 GHz of continuous self-pulsation frequency tunability using two active sections.