Search

Optimization and characterization of multiple InGaAsN/GaAs quantum-well laser diodes for high frequency operation are reported. From the modelling of the dilute nitride quantum well, we investigate how to design the structure to achieve a high frequency operation. The gain characteristics are optimized by incorporating the minimum amount of nitrogen in the well to obtain the emission at 1.3 μm with a low transparency density and a high differential gain. We show that the number of wells must be adjusted to three to benefit of the best compromise between the threshold current and the differential gain. The effects of the cavity losses on the dynamic characteristics are evaluated and demonstrate the interest for high cavity losses to reach high relaxation frequency despite a lower characteristic temperature. An optimized structure has been realized and exhibits an emission at 1.34 μm with a transparency current density of 642 A/cm2 and a characteristic temperature T0 ~ 80 K. Dynamic properties for ridge devices are evaluated from relative intensity noise measurements and small-signal modulation. A relaxation frequency as high as 7.4 GHz and a 9.7 GHz small-signal bandwidth are reported. We demonstrate transmission up to 10 Gb/s at 25°C without penalty and bit error floor.

Static performances and high-frequency characterisation of a GaInNAs/GaAs laser diode emitting at 1.35 μm are reported. Optimised molecular beam epitaxial (MBE) growth has allowed the achievement of a triple quantum well stack for improved dynamic properties. Broad area lasers exhibit a transparency current density of 642 A/cm2 at 20°C under pulsed operation and a characteristic temperature T0 of 80 K. Single-mode narrow-ridge waveguide devices emitting at 1.34 μm demonstrate a low threshold current of 26 mA under continuous wave (CW) operation at 25°C for an HR/as-cleaved cavity. The maximum output power reaches 9 mW with a slope efficiency of 0.13 W/A under CW operation. Intrinsic dynamic properties of the devices have been evaluated through relative intensity noise (RIN) measurements and small signal modulation. The dependence of the relaxation frequency on the bias current shows a slope of 0.92 GHz/mA1/2. The evolution of the damping factor against the squared relaxation frequency gives a K factor of 0.44 ns. RIN measurements yield a record relaxation frequency of 7.4 GHz for this triple-QW device. Small signal modulation shows a 3 dB bandwidth of 9.7 GHz for this new material system, compatible with 10-Gbit/s applications.

We demonstrate electrical wavelength tuning by mode locking of an external cavity laser (ECL) with linearly chirped fiber Bragg grating (LCFBG). The configuration consists of a laser chip providing the gain coupled to an LCFBG with a large chip rate of 10 or 55 nm/cm providing the counter-reaction for laser oscillation. The laser chirp is electrically modulated by a sinusoidal signal in such a way that the ECL is mode locked. By changing the modulation frequency, a wavelength tuning range of 27 nm is achieved with the 10 nm/cm LCFBG, and a partial tuning range over 41 nm is demonstrated with the 55-nm/cm LCFBG. The output pulse stream at a specific mode-locking frequency and a corresponding wavelength is obtained for both positively and negatively chirped grating. A time bandwidth product reduction is measured in the case of negatively chirp grating when compared with positively chirp grating. A simple general law between the laser parameters is given (locking frequency, tuning range, and FBG chirp value). The parameters for a 40-nm tunable source modulated at 10 GHz are given. This simple tuning mechanism is very well adapted for a structure that requires accurate wavelength monitoring.

We developed a 10-Gb/s AlGaInAs colorless remote amplified modulator with a gain peak detuned semiconductor optical amplifier using a selective epitaxy and semi-insulating buried heterostructure. The device provides up to 10-dB insertion gain and lossless operation together with static extinction ratio larger than 20 dB over a 50-nm range. Using this device, we achieved 10-Gb/s remote modulation over 80-nm spectral range in a back-to-back transmission. The device operates also in a single-mode fiber bidirectional link without penalty at 20 $^{\circ}$ C.

Dans ce travail, un absorbant saturable est utilise pour ameliorer le taux d'extinction d'un train d'impulsions picosecondes cadence a 160-GHz et centre sur 1555 nm. Une amelioration du taux d'extinction de 6 dB est observee sur une plage de longueur d'onde de 8 nm.

We demonstrate an easy and efficient step tunable sampled fiber Bragg grating (SFBG) external cavity laser. A small current variation applied to a single electrode induces a step tuning of 15 nm based on the Vernier effect between an SFBG with a comb-like reflectivity and a two-section semiconductor laser diode. Thanks to the low current variation of less than 3 mA in the phase section, the output power remains constant within 0.6 dB at 6 dBm. The side-mode suppression ratio is greater than 40 dB over the whole tuning range.

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.

We propose a hybrid wavelength-division-multi-plexing/time-division-multiplexing architecture using reflective semiconductor optical amplifiers (RSOAs) for next-generation access solutions. We demonstrate that the use of a high gain and high output power RSOA as remote modulator enables a 36-dB optical budget for colorless operation at 2.5 Gb/s over 45-km single-mode fiber. This RSOA-based configuration provides a reasonable cost per user for this hybrid system and can be easily upgraded.

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 report a compact hybrid photonic-integrated optical device consisting of AlGaInAs/InP electroabsorption modulators and a four-arm silica-on-silicon planar lightwave circuit optical interferometer. We use the device to generate 50-Gb/s NRZ-DQPSK signal with excellent performances comparable to those of the commercial lithium niobate DQPSK modulators, while requiring only 2.5Vpp drive signals.

We integrated an AlGalnAs modulator-amplifier using semi-insulating buried hetrostructure and selective area growth. The reflective component exhibits insertion gain, operates at 10Gbit/s over 80nm and links bi-directional 10km SMF up to 60°C.

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 report generation of 80-Gb/s RZ-OOK signals using a hybrid photonic integrated electroabsorption device. We achieve this using electronics having a bandwidth of 40 GHz or less and without using an external optical pulsed source.

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.

New self thermal compensated Single Active Layer AlGalnAs EML demonstrates 43 Gb/s open-eye operation for temperatures ranging between 10°C and 70°C. The dynamic extinction ratio over the whole temperature range was above 10 dB.

This paper investigates the performance of a reflective semiconductor optical amplifier in a bidirectional wavelength-division multiplexed passive optical network at 2.5 and 5 Gbit/s over 20 and 15 dB link budget.

Large positive detuning is used for self thermal compensation of threshold and power variation in AlGalnAs DFB. 25 km uncompensated and non-amplified SMF transmissions are demonstrated at a constant bias current from 20°C to 90°C.

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.

AlGalnAs large spectral range EAM has been integrated with SOA using Single Active Layer technology. The device operates as a 10Gbit/s drop & continue colorless element in a 50nm spectral range up 60°C

Single Active Layer is used for self thermal compensation of threshold and power variation in AlGalnAs EML. 90km SMF up to 60°C and 50km SMF up to 70°C trans missions are demonstrated.

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.

For high speed remote colorless modulation in FTTH technology, a new 10Gbit/s monolithically integrated amplified reflective electroabsorption modulator (R-EAM-SOA) is demonstrated over 50nm spectral range and over 20°C-60°C, with excellent eye diagrams.

For high speed remote colorless modulation in FTTH technology, a new 10Gbit/s monolithically integrated amplified reflective electroabsorption modulator (R-EAM-SOA) is demonstrated over 50nm spectral range and over 20°C-60°C, with excellent eye diagrams.

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.

A very low-loss and low switching energy vertical micro-cavity has been developed for all-optical signal reshaping. This saturable absorber-based device shows insertion loss as low as 0.2 dB and a switching energy of 13 μJ/cm2 while keeping a response time lower than 5 ps. Such a low loss and low switching energy device has high potential applications in 2R regenerated transmission lines

We report on 800 fs pulse generation, at 134 GHz, using a Fabry-Perot quantum dash laser at 1.56 /spl mu/m. A 50 kHz RF spectral linewidth at 42 GHz is also demonstrated.

International audience; A vertical-access passive all-optical gate has been used to improve the extinction ratio of a 160 GHz pico-second 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 (211) regeneration at 160 Gbits/s.

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.

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)

International audience; Giant effective linewidth enhancement factors, close to 60, are measured on a quantum dot laser under specific biasing conditions. Consequently, 2.5 Gbit=s purely frequency modulated signal is obtained by direct current modulation at this operation point.

Measurements of SOA with various optical confinements show that low confinement devices are not saturated by ASE. This allows them to have good inversion factors at their input section, which leads to state-of-the-art noise factors.

We demonstrate ~500 fs pulse generation at a 53 GHz repetition rate using a two-section mode-locked quantum dot laser emitting at 1.56 μm. A very low 47 kHz linewidth of the carrier frequency at 43 GHz is reported. (2 pages)

We present a 22 mW-16nm tunable DBR-SOA, robust and simple to control. Less than 12 ns tuning speed is obtained by electrical pattern optimisation, and 10 Gb/s reconfigurable wavelength conversion compatible with packet switching is demonstrated. (2 pages)

We report on low-power optical bistability in a vertical cavity structure at 1.55-/spl mu/m wavelength due to the bandgap resonant dispersive optical nonlinearity of InGaAsP. In this structure, a GaAs-AlAs Bragg reflector grown on GaAs and the nonlinear medium grown on InP are bonded through wafer-fusion, leading to a high-quality vertical cavity after deposition of a top dielectric mirror. This device shows interesting characteristics for optical switching applications at fiber communication wavelengths, such as a switching contrast higher than 8:1 in the reflective mode and a bistability threshold power as low as 0.6 mW. True steady-state memory effect is observed with continuous-wave input, and the device switching time is in the ns range.

Saturable absorber comprised inside a suited micro-cavity has been fabricated and characterized through a dynamic wavelength conversion experiment. Wavelength conversion is observed within a 40nm bandwidth, and is effective within a 15nm bandwidth.

All-optical regeneration devices based on semiconductor microcavity have been designed with different numbers of quantum wells inside. The switching energy is strongly dependent of the quantum well number.

27 nm electrical wavelength tuning of external cavity laser with linearly chirped fiber Bragg grating (LCFBG) has been demonstrated. Wavelength tuning has been achieved by changing the modulation frequency around 2.1 GHz.

A current variation less than 3 mA applied to a single electrode induces a step tuning of 15 nm in a sampled fiber Bragg grating external cavity laser. The output power is 6 dBm and side mode rejection -40dB.

Summary form only given. A novel and very simple approach is demonstrated for strained layer InGaAsP MQW distributed feedback laser-electroabsorption modulator monolithic integration with very high performance at 1.5 /spl mu/m (13.6 dB extinction ratio at 1.5 V operating voltage for a 70 /spl mu/m long modulator).

In situ fully electrical monitoring of the reflectivity of antireflection coatings on semiconductor laser facets is experimentally demonstrated. The operating principle consists of detecting changes in the forward voltage drop induced by the modification of facet reflectivity of a constant current‐driven semiconductor laser. This technique allows one to detect the optimum thickness giving the lowest reflectivity without optical measurement. A reflectivity as low as 1×10−4 was currently obtained with electron beam deposited SiOx films on 1.5 μm buried ridge stripe lasers.

Room temperature optical variable delays are demonstrated using InAs/InP quantum dash semiconductor optical amplifiers (SOAs) at 1.55 μm. A microwave frequency modulated single optical beam allows to demonstrate fast light through the achievement of maximum optical delays of 136 ps at 250 MHz and ∼55 ps at 2 GHz by means of electrical control of the SOA bias current. The group index variation is attributed to enhanced nearly degenerate four wave mixing of this material system as well as population pulsation.

We report a novel hybrid integrated optic device consisting of AlGaInAs/InP electroabsorption modulators and a four-arm silica-on-silicon planar lightwave circuit optical interferometer. The device is designed for generation of high spectral efficiency optical modulation formats. We demonstrate generation of 21.4 Gb/s quadrature phase shift keyed optical signals with electrical data drives of 2V(pp) amplitudes, achieving a bit error rate of 10(-9) with the required optical signal to noise ratio of ~18 dB in a 0.1 nm resolution bandwidth.

We demonstrate passive mode locking in one-section monolithic semiconductor laser diodes based on quantum-dash active layer at very high repetition rate in the 1.5μm window. Transform-limited pulses are generated at 134GHz with subpicosecond width, without any pulse compression scheme. A 50kHz linewidth of the radio-frequency spectrum is also demonstrated at 42GHz, the lowest value reported for any passively mode-locked semiconductor laser. We further show that the saturable absorption section in two-section devices has no significant impact on the mode-locking behavior.

Several all-optical switching devices based on quantum well microcavity structures have been studied in view of their possible use for all-optical regeneration of telecommunication signals. Experiments and modeling show that the saturation energy is inversely proportional to a scaling factor describing the enhancement of the intracavity intensity at the Fabry-Perot resonance. As a result the saturation energy is approximately proportional to the number of quantum wells in the device and can be kept small by a proper cavity design.

High frequency characterisation of three-quantum well GaInNAs/GaAs lasers operating at 1.35 µm is reported. A relaxation frequency as high as 7.4 GHz and a 9.7 GHz small-signal bandwidth are demonstrated, indicating the potential for high bit rate (10 Gbit/s) direct modulation of these dilute nitrides on GaAs devices.

An all-optical fast wavelength switching at 10 Gbit/s between 200 GHz-spaced channels using a digitally tunable external cavity laser and semiconductor optical amplifier-based wavelength converter is demonstrated.

A flat-response multi-peak sampled fibre Bragg grating has been realised using a novel fabrication technique and has been used in a widely tunable hybrid semiconductor laser. The laser shows 45 nm tunability in C-band and sidemode rejection better than 35 dB for all wavelengths.