Search

We have designed, fabricated and characterized an electro-absorption modulator integrated with generic technology on a semi-insulating substrate. The modulator operates at 64Gb/s with 6dB dynamic extinction ratio, a bias voltage of -2.2V and a voltage swing of 3.5V.

We demonstrate an InP-based photonic multiwavelength transmitter realized by integrating an array of distributed Bragg reflector lasers with modulators in Mach-Zehnder configuration. An arrayed waveguide grating is used to multiplex the generated signals into a common optical output. The device is designed according to a generic integration concept, using standardized building blocks, and is fabricated in a multiproject wafer run. The device delivers up to 4 dBm of optical power into the fiber with a modulation data rate of 12.5 Gbps per transmission channel. The obtained performance makes it very promising for application in the next generation optical access networks as a key source in the central office part of the telecommunication systems.

International audience; Injection-locked quantum dash laser exhibits a different FM-to-AM ratio as compared to the solitary one.Optical injection enhances the FM-AM phase difference. The linewidth enhancement factor can no longer becharacterized by the FM/AM technique.

International audience; It is well known that current modulation in diode lasers generates amplitude (AM) and optical frequency (FM) modulations. The frequency chirp under direct current modulation originates from variations in the carrier density and from the finite difference in carrier density between the laser on and off states. Modulation of the carrier density modulates the gain and the optical index causing the resonant mode to shift. This frequency chirp broadens the spectrum, which is a serious limitation for high-speed applications and optical fiber communications. At low frequencies, thermal effects also alter the frequency chirp. The aim of this paper is to show that the laser’s frequency chirp can be modified using an external control technique. The chirp response is evaluated via the determination of the chirp-to-power ratio (CPR) through a Mach-Zehnder interferometer. Experiments demonstrate that when an external optical feedback is properly adjusted, the CPR can be severely decreased over a wide range of modulation frequencies as compared to the free-running case. These preliminary results obtained on quantum well distributed feedback lasers (QW DFB) with low normalized coupling coefficient (􏰀L) demonstrate how to stabilize the CPR through the DFB facet phase effects or parameters such as the linewidth enhancement factor. In order to confirm this frequency chirp engineering, self- consistent calculations based on the transfer matrix method are also presented.

International audience; The temperature dependence of the dynamic performance of p-doped InAs/GaAs quantum-dot distributed feedback (DFB) lasers emitting at 1.3 µm is investigated. A maximum relaxation frequency of ~7 GHz is demonstrated for a constant bias current over the whole 25°C-85°C temperature range. The Henry factor is temperature independent and remains constant at ~2.5. The effect of external optical feedback is assessed on the same device in a 10-Gb/s transmission over 20 km

International audience; This paper reports on the tolerance of low-dimensional InAs/InP quantum-dash- and quantum-dot-based semiconductor lasers to optical feedback in the 1.55 mum window. For this purpose, the onset of coherence collapse (CC) is experimentally determined and systematically investigated as a function of different laser parameters, such as the injection current, differential gain, temperature, and photon lifetime. It is in particular found that for both material systems the onset of CC increases with the injection current in a similar way to bulk or quantum-well-based devices. Of most importance, we experimentally show that the differential gain plays a key role in the optical feedback tolerance. It is indeed shown to determine not only the range of the onset of CC but also the dependence of this threshold both on the temperature and laser cavity length. Increasing the operating temperature from 25degC to 85degC leads to a decrease of the onset of CC by a factor of only ~3 dB, well accounted for by the variation of the differential gain in this temperature range. We find no difference in the tolerance to external reflections of a truly 3-D confined quantum-dot-based laser and a quantum dash device of the same cavity length, which have similar differential gains. A tentative analysis of our data is finally carried out, based on existing models.

The performances of a novel low-chirp electroabsorption modulator laser module are presented. Transmission is analysed in standard singlermode fibre at 40 Gbit/s. Propagation without chromatic dispersion compensation up to 2 km exhibits a low penalty variation over a wide temperature range. A propagation scheme with compensation leads to negligible impairment at 88 km.

The alphaH-factor behavior with current is investigated in a 1.52 mum InAs/InP (311B) QD laser. It is shown that due to low gain compression effects, no divergence of the alphaH-factor occurs unlike 1.3 mum InAs/GaAs QD lasers.