Photonic microwave oscillator based on monolithic DFB lasers with frequency-shifted feedback

International audienceA photonic oscillator, locked to a master RF synthesiser, was built by using a monolithic dual-wavelength DFB semiconductor laser submitted to a frequency-shifted optical feedback. A [3; 10] GHz tuning range is reported, with a phase noise level lower than −70 dBrad2/Hz at a 10 Hz offset from the carrier

Transmission Quality Measurement of Two Types of 60 GHz Millimeter-Wave Generation and Distribution Systems

International audienceIn this paper, we demonstrate and compare experimentally two techniques achieving very high-data-rates (> 1 Gb/s) wireless transmission in the 60 GHz window using radio over fiber (RoF) for reach extension. The first RoF link is based on a 10 GHz vertical-cavity surface-emitting laser and uses a multimode fiber. The radio signal is transported on an intermediate frequency of 4.5 GHz and electrically upconverted to 60 GHz after the optical link. The second uses an optical frequency upconversion from 4.5 to 60 GHz by direct modulation of a mode-locked Fabry-PEacuterot laser whose self-pulsating frequency is 54.8 GHz before transmission over a single-mode fiber. For both techniques, two different types of modulation were tested. The first one was an on-off keying at 1.5 Gb/s and the second one was an orthogonal frequency-division multiplexing-QPSK signal compliant to the IEEE 802.15.3.c prestandard (3.03 Gb/s). Radio propagation performance is also reported

Comparison of two types of 60 GHz photonic millimeter-wave generation and distribution of a 3 Gb/s OFDM signal

International audienceWe demonstrate and compare experimentally two set-ups achieving very high data rate (3 Gbps) wireless transmission in the 60 GHz window, both using Radio-over-Fiber (RoF) for reach extension with OFDM signal compliant to the IEEE 802.15.3.c pre-standard

Coherent terahertz photonics

We present a review of recent developments in THz coherent systems based on photonic local oscillators. We show that such techniques can enable the creation of highly coherent, thus highly sensitive, systems for frequencies ranging from 100 GHz to 5 THz, within an energy efficient integrated platform. We suggest that such systems could enable the THz spectrum to realize its full applications potential. To demonstrate how photonics-enabled THz systems can be realized, we review the performance of key components, show recent demonstrations of integrated platforms, and give examples of applications

Monolithic dual-wavelength DFB lasers for the generation of optically carriedRF local oscillators

International audienc

Développement de composants de puissance pour la réalisation de liaisons optiques hyperfréquences de grande dynamique

Les liaisons optiques hyperfréquences présentent aujourd'hui des intérêts pour les oscillateurs opto-électroniques, la radio sur fibre ou le déport à la réception de signaux analogiques. Dans les radars par exemple, le déploiement de liaisons optiques analogiques en lieu et place de câbles coaxiaux est déjà une réalité [1]. Les principaux avantages des liaisons optiques sont la réduction de taille et de masse, les faibles pertes de propagation ou l'immunité électromagnétique et sont dus à l'utilisation de la fibre optique. Depuis une vingtaine d'année, plusieurs types de liaisons optiques hyperfréquences ont été rapportés : modulation directe ou externe, détection directe ou différentielle, avec réduction du bruit [2]. Par rapport aux liaisons à modulation directe, les liaisons à modulation externe permettent généralement de meilleures performances en termes de bande passante, de gain ou de dynamique. Cependant malgré de moins bonnes performances, la compacité et le faible coût des liaisons à modulation directe en font un candidat potentiellement très attractif jusqu'à 6 GHz, en remplacement des câbles coaxiaux. Dans cet article, nous présentons le développement d'une source laser DFB de puissance et d'une photodiode UTC ayant des performances spécifiques pour la transmission de signaux analogiques. Grâce à ces deux composants, nous avons démontré des performances de liaisons optiques en bande L et S à l'état de l'art, alliant fort gain, point de compression élevé et large dynamique (SFDR)

Thermal dissipation in InP based optical lasers and amplifiers

International audienceIn a semi-conductor optical amplifier (SOA) or a laser, the behavior of the device can be effected the temperature elevation due to high current injection level in the chip and a limited efficiency. For example, the optical output power of a laser or the optical gain in a SOA is reduced when the temperature of the junction increases. This latter can be controlled or monitored thanks to a thermo-electronic cooler (or a Peltier element) and a thermistor. In this paper, we calculate the thermal dissipation in semiconductor Optical Amplifier and laser. We investigate the effect of the material composition, the number of wells, the type of structure (Buried or Ridge), on the thermal resistance of the component and try to extract some rules towards minimization of temperature elevation. The influence of heat repartition inside the wells has been evaluated as well as the use of thick asymmetric cladding layer in the structure. In the latter case, optimization of layer composition and waveguide dimension has been performed