Liquid crystal micro-cells for tunable VCSELs

International audienceWe recently demonstrated the tunability of a VCSEL with an intra-cavity liquid crystal layer. This demonstration was made on a macroscopic-sized sample with optical pumping. For a further development of this solution, it is necessary to place the liquid crystal on microscopic VCSEL chips. We developed a microtechnology process which makes it possible to fabricate liquid crystal micro-cells in a collective process

InAs quantum wires on InP substrate for VCSEL applications

International audienceQuantum dash based vertical cavity surface emitting lasers (VCSEL) on InP substrate are presented. Single and close stacking layers were successfully grown with molecular beam epitaxy. Optimized quantum dash layers exhibit a strong polarized 1.55 µm photoluminescence along the [1-10] crystallographic axis. Continuous wave laser emission is demonstrated at room temperature for the first time on a quantum dash VCSEL structure on InP susbtrate. The quantum dash VCSEL laser polarization appears stable on the whole sample and with excitation, no switching is observed. Its polarization is mainly oriented along [1-10], an extinction coefficient of 30 dB is measured. Those preliminary results demonstrate the interests of quantum dashes in the realization of controlled and stable polarization VCSEL device

Liquid crystal micro-cells: collective fabrication of individual micro-cells

International audienceWe developed a micro technology process which enables the fabrication of microscopic individual liquid crys-tal cells. With a dimension close to 500 μm, they are the smallest inde-pendent cells manufactured to this day and can be placed on several kinds of substrates. One of our goals is to use these micro-cells for the fabrication of tunable VCSEL chips

Collective constructions with micro-bricks. Application to the fabrication of liquid crystal micro-cells

International audienceWe present a method that makes it possible to deposit and bond micro-elements on an underlying device. In this manner, micro-constructions can be built by the addition of micro-bricks. The elements are fabricated on a flexible substrate covered with a release coating and are subsequently transferred and bonded onto the target device in a collective process. The process works on complex geometries and can accommodate surface defects, while maintaining a tightly controlled geometry. Application to the fabrication of liquid crystal micro-cells is presented

Polarization splitter made of a polymer waveguide coupler with localized anisotropic segments

International audiencePolarization splitters are important functions in integrated-optic devices for managing polarization diversity. We present the fabrication and characterization of polymer waveguide couplers with localized anisotropic segments in the coupling region. The core of the waveguide is made of a polymerizable liquid crystal that is thermally patterned into isotropic and anisotropic regions before etching. For an appropriate coupling length, the coupler behaves as a polarization splitter: the horizontal polarization remains on the direct waveguide, while the vertical polarization is totally transferred to the coupled waveguide. This fabrication technique and the resulting couplers are useful elements for the development of polymer integratedoptic devices

Réalisation de micro résonateurs intégrés en polymère et de fonctions associées

session 2 " Matériaux et technologies pour la photonique (2) " [MTP]National audienceLes micro-résonateurs intégrés peuvent permettre de faire des fonctions miniaturisées très intéressantes de par leur grande sensibilité et leur petite taille. Nous montrerons quelques résultats et des fonctions qui sont envisagées au CCLO avec des micro-résonateurs intégrés en polymère permettant notamment d'obtenir d'excellentes caractéristiques de filtrage

Polymer waveguides featuring isotropic and anisotropic sections: Application to the fabrication of polarization splitters

International audienceWe present the fabrication of single-mode polymer waveguides featuring both isotropic and anisotropic sections on the same substrate. The core of the waveguide is made of a polymerizable liquid crystal, which is thermally patterned into isotropic and anisotropic regions before etching. Simulation is performed in order to design polarization-separating couplers. The technological fabrication is then presented as well as a first realizatio

Tunable semiconductor vertical-cavity surface-emitting laser with an intracavity liquid crystal layer

International audienceA tunable vertical-cavity surface-emitting laser is fabricated where tunability is achieved with an intracavity layer of nematic liquid crystal and gain is provided by a semiconductor quantum well structure. The anisotropic liquid crystal layer enables a continuously tunable single-mode emission along the extraordinary axis of the layer. Polarization control is achieved when the layer thickness is such that the ordinary modes are out of the spectral gain region. Laser emission in the 1.5µm telecom wavelength range is demonstrated under optical pumping with a tuning range of more than 30 nm for an applied voltage of less than 3V

Tunable VCSEL with intracavity liquid crystal layer

International audienceA tunable VCSEL is demonstrated, where tunability is achieved with an intracavity nematic liquid crystal layer. Laser effect is obtained under optical pumping. By choosing an adequate cavity length, it is possible to obtain a single mode emission on the extraordinary mode. A tuning range of more than 30 nm is demonstrated, with an applied voltage of less than 3 V