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Ustawodawca z różnych przyczyn przekazuje do rozpoznania przez sądy powszechne sprawy administracyjne. Sprawy te załatwiane są przez organ administracyjny decyzją, a odwołanie kierowane jest do sądu powszechnego. Przykładem takiej procedury, zwanej hybrydową, jest postępowanie w sprawach z zakresu ubezpieczeń społecznych.

Background The aim of this study was to determine whether spinal cord stimulation (SCS) using 3D neural targeting provided sustained overall and low back pain relief in a broad routine clinical practice population. Study Design and Methods This was a multicenter, open-label observational study with an observational arm and retrospective analysis of a matched cohort. After IPG implantation, programming was done using a patient-specific, model-based algorithm to adjust for lead position (3D neural targeting) or previous generation software (traditional). Demographics, medical histories, SCS parameters, pain locations, pain intensities, disabilities, and safety data were collected for all patients. Results A total of 213 patients using 3D neural targeting were included, with a trial-to-implant ratio of 86%. Patients used seven different lead configurations, with 62% receiving 24 to 32 contacts, and a broad range of stimulation parameters utilizing a mean of 14.3 (±6.1) contacts. At 24 months postimplant, pain intensity decreased significantly from baseline (ΔNRS = 4.2, N = 169, P

When elliptically polarized maximally entangled states are considered, i.e., states having a non random phase factor between the two bipartite polarization components, the standard settings used for optimal violation of Bell inequalities are no longer adapted. One way to retrieve the maximal amount of violation is to compensate for this phase while keeping the standard Bell inequality analysis settings. We propose in this paper a general theoretical approach that allows determining and adjusting the phase of elliptically polarized maximally entangled states in order to optimize the violation of Bell inequalities. The formalism is also applied to several suggested experimental phase compensation schemes. In order to emphasize the simplicity and relevance of our approach, we also describe an experimental implementation using a standard Soleil-Babinet phase compensator. This device is employed to correct the phase that appears in the maximally entangled state generated from a type-II nonlinear photon-pair source after the photons are created and distributed over fiber channels., 8 pages

We investigate the influence of nonlinear optical Faraday rotation on polarization multistability and modulational instabilities in nonlinear resonators. The potential use of gyrotropic cavities for implementing a light polarization-controlled set–reset flip–flop element and a high-repetition-rate pulse train generator is analysed.

A theoretical investigation of the performance of single-mode coupled spontaneous parametric downconversion sources is proposed, which only requires very few assumptions of practical interest: quasi-degenerate collinear generation and narrow bandwidth obtained through spectral filtering. Other assumptions, such as pump-beam spatial and temporal envelopes, target single-mode profile and size, and nonlinear susceptibility distribution, are only taken into account in the final step of the computation, thus making the theory general and flexible. Figures of merit for performance include absolute coupled brightness and conditional coupling efficiency. Their optimization is investigated using functions that only depend on dimensionless parameters, so that the results provide the best experimental configuration for a whole range of design choices (e.g., crystal length, pump power, etc.). A particular application of the theory is validated by an experimental optimization obtained under compatible assumptions. A comparison with other works and proposals for numerically implementing the theory under less stringent assumptions is also provided.

Fast and complete characterization of pulsed spontaneous parametric down conversion (SPDC) sources is important for applications in quantum information processing and communications. We propose a simple method to perform this task, which only requires measuring the counts on the two output channels and the coincidences between them, as well as modeling the filter used to reduce the source bandwidth. The proposed method is experimentally tested and used for a complete evaluation of SPDC sources (pair emission probability, total losses, and fidelity) of different bandwidths. This method can find applications in the setting up of SPDC sources and in the continuous verification of the quality of quantum communication links.

We have experimentally implemented the distribution of photon pairs produced by spontaneous parametric down conversion through telecom dense wavelength division multiplexing filters. Using the measured counts and coincidences between symmetric channels, we evaluate the maximum fringe visibility that can be obtained with polarization entangled photons and compare different filter technologies., Comment: 3 pages, 4 figures, submitted to Optics Letters

We consider the Raman amplification problem for silicon waveguides in the regime in which both the pump and signal pulses are relatively short but wide enough that their duration exceeds the phonon lifetime (about 3 ps in silicon). We use the coupled pump-signal equations for numerical simulations that include all competing nonlinear effects such as self- and cross-phase modulations, two-photon and free-carrier absorptions, and changes in the refractive index induced by the free carriers. However, numerical simulations do not provide much physical insight. For this reason, we also develop an approximate analytic approach for solving the Raman amplification problem. We introduce the concept of an effective Raman gain and show analytically how it depends on the pump bandwidth. As the pump spectrum broadens inside the silicon waveguide, the effective Raman gain is reduced considerably. We obtain an analytical form of the nonlinear phase accumulated during propagation inside a silicon waveguide and use it to calculate the total spectral broadening experienced by a pump pulse. Using this result, we can predict changes in the effective Raman gain as a function of pump pulse energy. A comparison of our predictions with the recent experimental data shows that our model is reasonable and captures the essential physics.

We experimentally and theoretically study self-phase modulation by Kerr effect in a liquid filled hollow core photonic crystal fiber. We perform a complete characterization of the linear optical properties of the hollow core photonic band gap fiber filled with deuterated acetone to determine all the characteristics of the propagation mode. The nonlinear coefficient of the fiber is determined by fitting the output spectra broadened by self-phase modulation with a new analytical expression giving the spectra of a secant hyperbolic pulse transmitted through a Kerr media. The experiment allows a precise determination of the nonlinear index change of acetone-d6 equal to (1.15$\pm$0.17)x10-19 m2W-1., to be published in JOSAB

We experimentally show that the self-phase modulation of picosecond pump pulses, induced by both the optical Kerr effect and free-carrier refraction, has a detrimental effect on the maximum on-off Raman gain achievable in silicon on insulator nanowaveguides, causing it to saturate. A simple calculation of the Raman gain coefficient from the measured broadened output pump spectra perfectly matches the saturated behavior of the amplified Raman signal observed experimentally at different input pump powers., Accepted for publications in Applied Physics Letters

A new filtering technique is proposed that associates the high dispersion of standard reflection gratings with the tuning speed of acousto-optic cells. Tuning is performed by adjusting the grating period so that the chosen wavelength is at Bragg resonance. In this way, the selected wavelength always experiences a maximum diffraction efficiency, ensuring good uniformity. Using a commercial acousto-optic modulator, a wavelength selectivity of 0.075 nm is demonstrated together with a uniformity of ±0.2 dB on a tuning range of 2.2 nm corresponding to N = 30 resolvable frequencies. N > 600 could be obtained with an acousto-optic cell specially designed for this device.

The ability of two-dimensional (2D) photonic crystals (PC) for high enhancements of nonlinear processes is analyzed in the case of a degenerate band edge when two symmetrical diffracted beams are generated by Bragg diffraction in the 2D-PC. Calculations are performed using the very simple Bragg-coupled wave theory which only involves three coupled waves (the incident wave and the two diffracted waves) for the linear interaction. The validity of the approximation is proved for wavelengths lying at the neighborhood of the band edges of 2D-PC. Very large local-field intensities are predicted around the band-edge wavelengths, in particular for the upper band edge. Nonlinear propagation is studied through the analysis of degenerate four-wave mixing. For counterpropagating pump beams orthogonally sent onto the 2D-PC huge improvement of the phase conjugate reflectivity are predicted at least for small incidence angles of the signal beam. These results represent an improvement by a factor of 20 when compared to the case of a one-dimensional PC of the same thickness made of the same materials. As three intense phase conjugate beams are generated in the four-wave mixing interaction, the 2D-PC could be very interesting for the purpose of dense parallel optical signal processing. Moreover, the simple theoretical analysis developed in the paper can be used for any kind of 2D-PC.

International audience; A very simple model has been developed to describe the diffractive properties of a crossed grating structure of the refractive index formed by a thin transmission grating recorded in a Bragg reflector. When the Bragg condition of the transmission grating coincides with the band edge of the reflection grating seen as a one dimensional photonic crystal, the diffraction efficiency and wavelength selectivity of the transmission grating are highly enhanced and a Bragg diffraction regime can be obtained, even in very thin samples. The model can be used to design micrometric very efficient new diffracting devices for optical signal processing

Nonlinear propagation experiments in GaAs photonic crystal waveguides (PCW) were performed, which exhibit a large enhancement of third order nonlinearities, due to light propagation in a slow mode regime, such as two-photon absorption (TPA), optical Kerr effect and refractive index changes due to TPA generated free-carriers. A theoretical model has been established that shows very good quantitative agreement with experimental data and demonstrates the important role that group velocity plays. These observations give a strong insight into the use of PCWs for optical switching devices., Comment: 6 pages

International audience; Highly improved diffraction properties are demonstrated in a two-dimensional [2D] grating consisting of a transmission grating optically recorded in a semiconductor one-dimensional photonic crystal (1D-PC). Near unity internal diffraction efficiency, high wavelength selectivity, and Bragg diffraction regime operation are demonstrated when the read beam is set at Bragg incidence on the transmission grating while its wavelength corresponds to the band edge of the 3 um thick 1D-PC. When the 2D grating is grown on a Bragg mirror, a single diffracted beam is obtained, which makes the device promising for optical signal processing

5 pages; International audience; An optical parametric oscillator for the infrared region pumped by a picosecond Ti:Sapphire laser is demonstrated. Fourier transform limited pulses of 15 and 10 ps, for signal and idler wavelengths respectively, have been obtained using a periodically poled stoechiometric lithium tantalate nonlinear crystal, without any spectral filtering. A complete experimental study of the influence of the cavity length detuning on the spectral and temporal dynamic of the output radiation is discussed.

International audience; Large refractive index changes have been measured at the band edge frequency of 1D photonic crystals. Results concerning both thin and thick samples of high and low refractive index contrast respectively are presented. The very large value of the refractive index changes obtained at moderate pump powers thanks to the strong enhancement of the local intensity inside the photonic crystal open the way to very small volume devices for optical signal processing. However, time-resolved experiments demonstrate the photo-generation of high free carrier densities through two- or even three-photon absorptions which are shown to be also strongly enhanced at the band edge of the photonic crystal. This drawback may the most probably be circumvented by using lower pump intensities in photonic crystals showing narrower resonances.

International audience; We report the results of an experimental investigation of the diffractive properties of a thick index grating embedded in a Fabry-Perot resonator, the so-called intracavity Bragg grating. We compare the performance of this device with that of a bare Bragg grating with same thickness and the same index modulation and establish the improvement in performance with the resonator. The experimental data also fit predictions calculated from a theoretical model.

International audience; Intracavity gain gratings are theoretically demonstrated to exhibit diffraction efficiencies that are 100 times larger than unity at pump powers substantially below the lasing threshold. Experiments performed using a Nd:YVO4 microlaser pumped below threshold by two interfering Ti:sapphire laser beams are described. Huge enhancement of the diffraction efficiency (5000x) and a large increase of the angular selectivity (10x) are demonstrated despite the angular reduction of the Fabry-Perot cavity finesse. Much better results are expected using gain gratings with larger areas or thinner cavities such as vertical cavity surfaceemitting lasers. Such large fan-out values could be very interesting for applications to optical signal processing.

We relate the optical activity in photonic crystals to a photospin-orbit interaction analogous to the electron spin-orbit interaction in asymmetric semiconductors and analyse its implications in photospin state manipulation and photospintronics as in electron spintronics.

International audience; We experimentally and theoretically analyze an original method based on two-wave mixing in an erbiumdoped fiber amplifier for optical carrier reduction of microwave signals. 75% optical carrier attenuation has been observed, and a 10 dB modulation depth increase of the microwave signal is experimentally demonstrated. Moreover, calculated results are in good agreement with measurements and predict that up to 80% carrier attenuation is easily possible.

We present here an experimental and theoretical study of two wave mixing by gain saturation in a diode pumped erbium doped polarisation maintaining fiber amplifier. Application to modulation depth enhancement of optically carried microwave signals is proposed and demonstrated.

International audience; A theoretical analysis of the Raman amplification in optical fibers and the pump-to-signal relative intensity noise (RIN) transfer has been performed in the spectral domain. An efficient Raman amplification of a monochromatic signal beam by a large-bandwidth pump beam has been demonstrated for a pump bandwidth much smaller than the Raman linewidth. Under the same approximation the pump-to-signal RIN transfer has been calculated in both cases of copropagating and counterpropagating beams in the two limiting cases of modulated monochromatic and smooth-profile large-bandwidth pump beams. At low frequencies the excess of noise evidenced in the case of a modulated monochromatic pump beam did not exist in the case of large-bandwidth pseudoincoherent sources. As this noise reduction can be as large as 13 dB for a 40 dB net gain of the amplifier, such incoherent pumping sources must be considered for the purpose of low-noise Raman amplifiers

International audience; Stimulated Raman amplification of optically carried microwave signals in optical fibers is experimentally investigated. In the backward configuration which is shown to be less noisy than the forward one, net amplification factors larger than 20 dB are demonstrated in the low signal regime with better relative intensity noise (RIN) values than using erbiumdoped fiber amplifiers. Due to the RIN flatness with respect to the gain of the stimulated Raman amplifier high quality variable gain amplification of optically carried microwave signals could be implemented using optimized Raman amplifiers

International audience; We show that high efficiency stimulated Raman scattering can be obtained using hollow core photonic crystal fiber with the core filled with a low refractive index nonlinear liquid. This new architecture opens new perspectives in the development of nonlinear functions as any kind of nonlinear liquid media can now be used to implement them, with original properties not accessible with silica core fibers

International audience; We present a modeling of a degenerate four-wave-mixing nonlinear process in one-dimensional photonic crystals. The model is based on the nonlinear extension of the transfer-matrix description of propagation in the structure. The influence of light localization, near the band edge of the structure, on the enhancement of the phase-conjugate reflectivity is studied. The phase-conjugate reflectivity is shown to increase as the eighth power of the number of layers with an additional large dependence on the index contrast of the structure. In both cases the enhancement is accompanied by a strong reduction of the resonance width, which may lead to some limitation of the enhancement when ultrashort pulses are used. A strong influence of the losses on the nonlinear efficiency of the structure is also predicted with a great importance of scattering losses at the multiple interfaces of the structure

International audience; The diffraction regime of a thin grating inserted in a Fabry-Perot cavity is investigated. Our calculations show that, at Bragg incidence, a single diffraction order can be selectively enhanced, giving rise to a very efficient Bragg-like diffraction regime. The optimization of the device is studied as a function of the resonator thickness and finesse and the grating position inside the Fabry-Perot cavity. The angular and wavelength selectivities are also investigated. The device could be easily integrated and would be very useful for optical signal processing applications.

International audience; We theoretically analyze a high-efficiency single-frequency Brillouin all-fiber ring laser at 1.5 mm wavelength, taking pump depletion into account. The output pump and Stokes intensities are calculated as functions of the cavity coupling coefficient and of the input pump intensity. Lasing threshold and pump-to-Stokes conversion efficiency are predicted. Furthermore, we demonstrate good agreement between model results and measurements. Applications to the improvement of optoelectronic links for radio-frequency signals by use of stimulated Brillouin scattering fiber lasers are also presented.

International audience; We experimentally demonstrate efficient optical carrier reduction of microwave signals with a single-mode 1.5-mm wavelength Brillouin all-fiber ring laser. Because of the tunable optical coupling, the lasing threshold of the short-length (20-m) fiber cavity is lower than 5 mW, and high conversion efficiencies (up to 60%) are obtained at any pump power up to _200 mW. Using the single-mode Stokes beam as a seed for the stimulated Brillouin scattering process allows up to 40-dB optical carrier depletion with almost no added noise for an optically carried microwave signal at 6 GHz. In addition, using this resonator, we provide evidence of generation of high-spectral-purity beatnotes.

International audience; The grating thickness limit lFP between the Raman-Nath and the Bragg diffraction regimes is calculated for an index grating placed in an asymmetric Fabry-Perot resonator with a totally reflecting back mirror and compared with that which was obtained for the same grating with no cavity lM . Owing to the increase of the effective interaction length inside the Fabry-Perot cavity, the stronger the front mirror reflectivity R1 of the cavity, the smaller the thickness above which the whole diffracted intensity can be concentrated into one unique diffracted beam: lFP=[(1−√R1)/(1+√R1)]lM/2.

Inmate contact with the correctional health care system provides public health professionals an opportunity to offer HIV screening to a population that might prove difficult to reach otherwise. We report on publicly funded human immunodeficiency virus (HIV) voluntary counseling, testing, and referral (VCTR) services provided to incarcerated persons in the United States. Incarcerated persons seeking VCTR services received pretest counseling and gave a blood specimen for HIV antibody testing. Specimens were considered positive if the enzyme immunoassays were repeatedly reactive and the Western blot or immunofluorescent assay was reactive. Demographics, HIV risk information, and laboratory test results were collected from each test episode. Additional counseling sessions provided more data. From 1992 to 1998, there were 527,937 records available from correctional facilities from 48 project areas; 484,277 records included a test result and 459,155 (87.0%) tests came with complete data. Overall, 3.4% (16,797) of all tests were reactive for HIV antibodies. Of reactive tests accompanied by self-reports of previous HIV test results (15,888), previous test results were 44% positive, 23% negative, 6% inconclusive or unspecified, and 27% no previous test. This indicates that 56% of positive tests were newly identified. During the study period, the number of tests per year increased three-fold. Testing increased among all racial/ethnic groups and both sexes. The largest increase was for heterosexuals who reported no other risk, followed by persons with a sex partner at risk. Overall, the greatest number of tests was reported for injection drug users (IDUs) (128,262), followed by men who have sex with men (MSM) (19,928); however, episodes for MSM doubled during the study, while for IDUs, they increased 74%. The absolute number of HIV-positive (HIV+) tests increased 50%; however, the percentage of all tests that were HIV+ decreased nearly 50% due to the increased number of tests performed. HIV+ tests fell 50% among blacks (7.6% to 3.7%), Hispanics (6.7% to 2.5%), and males (5.1% to 2.5%); 33% among females (4.5% to 3.1%); 95% among IDUs (8.6% to 4.4%); and 64% among MSM (19.3% to 11.8%). Among HIV+ episodes, those for IDUs dropped from 61.5% to 36.6%, while episodes for heterosexuals with no reported risk factor increased from 4.3% to 18.2%. The use of VCTR services by incarcerated persons rose steadily from 1992 to 1998, and 56% of HIV+ tests were newly identified. High numbers of tests that recorded risk behaviors for contracting HIV indicate that correctional facilities provide an important access point for prevention efforts.

We propose nonlinear Faraday rotation as a mechanism for achieving stable polarization mode locking of a soliton laser. We analyze by perturbation theory and beam-propagation simulations the interplay between bandwidth-limited gain, gain dichroism, and linear and nonlinear Faraday rotation.

We experimentally and theoretically study self-phase modulation by Kerr effect in a liquid filled hollow core photonic crystal fiber. We perform a complete characterization of the linear optical properties of the hollow core photonic bandgap fiber filled with deuterated acetone to determine all the characteristics of the propagation mode. The nonlinear coefficient of the fiber is determined by fitting the output spectra broadened by self-phase modulation with a new analytical expression giving the spectra of a hyperbolic secant pulse transmitted through a Kerr medium. The experiment allows a precise determination of the nonlinear index change nI2 of acetone-d6 equal to (1.15±0.17)×10−19 m2 W−1.

A fast tunable filtering technique is proposed associating a diffraction grating with an intracavity Bragg grating. The bandwidth and the tuning range of this filter can be easily adapted by changing the diffraction grating's orientation, or its period, and its response is uniform over the whole tuning range. A numerical simulation of the filter response to a Gaussian beam has been developed, and it fits the experimental results allowing a calculation of the performances that could be obtained with more specific elements. For example, using a commercial acousto-optic deflector would allow a separation of 500 frequencies. It would then be possible to have a tuning range of 100 nm with a bandwidth of 0.2 nm for optical telecommunications.

Two-dimensional photonic crystals composed of two orthogonal volume diffraction gratings have been photogenerated in photopolymers. When the read beam is set at the Bragg angle, the diffraction efficiency of the transmission grating is strongly enhanced at the band edge of the reflection grating recorded in the material. Such a device provides Bragg operation and enhancement of the diffraction efficiency of the thin diffraction grating together with good wavelength selectivity. Such advantages could be interesting for optical signal processing.

A solution for dynamically enhancing the modulation depth of optically carried microwave signals is presented. It is based on stimulated Brillouin scattering in photonic crystal fibres (PCFs) used in loop configuration. The behaviour of this nonlinear effect in this new type of fibre is compared, both experimentally and theoretically, to that observed in conventional optical fibres.

International audience; Kerr and four-wave mixing spectroscopy is shown to be a powerful technique to quantify the strong enhancement of the third-order optical nonlinear susceptibilities at the band edge of photonic crystals. Local field factors of about 5 are demonstrated for crossed Kerr effect and a narrow resonance peak observed for the conjugate reflectivity. Moreover, a reduction of the effective nonlinear susceptibility of the four-wave mixing process with increasing pump intensities is measured, which is due to different Kerr-induced blueshifts of the band edge for forward and backward pump beams and signal and conjugate beams. This observation definitely demonstrates the need for considering all the nonlinear processes for the optimization of nonlinear photonic crystals for a given application in optical signal processing

International audience; The diffraction of Gaussian beams on intracavity Bragg gratings is analyzed theoretically. For reasonable waists the associated beam divergence does not significantly influence the diffraction efficiency of such devices. Nevertheless, the tilt angle of the incident beam, imposed by the Bragg resonance condition, strongly reduces the diffraction efficiency at short grating periods. However, the angular selectivity can be maintained if the Fabry-Perot cavity is tuned to the incident beam direction, which allows the use of small-volume holograms together with a dense angular multiplex. This theoretical analysis can be applied to the optimization of the diffraction properties of Gaussian beams on any intracavity Bragg grating, which could then be used for freespace parallel signal processing.

Context.—Policies requiring confidential reporting by name to state health departments of persons infected with the human immunodeficiency virus (HIV) have potential to cause some of them to avoid HIV testing.Objective.—To describe trends in use of HIV testing services at publicly funded HIV counseling and testing sites before and after the implementation of HIV reporting policies.Design and Setting.—Analysis of service provision data from 6 state health departments (Louisiana, Michigan, Nebraska, Nevada, New Jersey, and Tennessee) 12 months before and 12 months after HIV reporting was introduced.Main Outcome Measure.—Percent change in numbers of persons tested at publicly funded HIV counseling and testing sites after implementation of confidential HIV reporting by risk group.Results.—No significant declines in the total number of HIV tests provided at counseling and testing sites in the months immediately after implementation of HIV reporting occurred in any state, other than those expected from trends present before HIV reporting. Increases occurred in Nebraska (15.8%), Nevada (48.4%), New Jersey (21.3%), and Tennessee (62.8%). Predicted decreases occurred in Louisiana (10.5%) and Michigan (2.0%). In all areas, testing of at-risk heterosexuals increased in the year after HIV reporting was implemented (Louisiana, 10.5%; Michigan, 225.1%; Nebraska, 5.7%; Nevada, 303.3%; New Jersey, 462.9%; Tennessee, 603.8%). Declines in testing occurred among men who have sex with men in Louisiana (4.3%) and Tennessee (4.1%) after HIV reporting; testing increased for this group in Michigan (5.3%), Nebraska (19.6%), Nevada (12.5%), and New Jersey (22.4%). Among injection drug users, testing declined in Louisiana (15%), Michigan (34.3%), and New Jersey (0.6%) and increased in Nebraska (1.7%), Nevada (18.9%), and Tennessee (16.6%).Conclusions.—Confidential HIV reporting by name did not appear to affect use of HIV testing in publicly funded counseling and testing programs.

Les réseaux de diffraction sont largement utilisés dans le traitement optique de l'information. Toutefois, les applications nécessitent des efficacités de diffraction importantes, d'excellentes résolutions dans le domaine des fréquences spatiales et des temps de réponses appropriés à la fonction recherchée (grande durée de vie pour les mémoires, temps de réponses rapide pour les opérations de traitements de l'information...). Ces qualités étant difficiles à obtenir à l'aide des matériaux existants, une solution consiste à placer le matériau non-linéaire à l'intérieur d'une cavité Fabry-Pérot, avec le double avantage d'obtenir une efficacité de diffraction fortement accrue et une résolution dans le domaine des fréquences spatiales améliorée. Le mémoire rapporte comment l'utilisation d'un milieu intracavité amplificateur permet d'accroître encore davantage la puissance du faisceau diffracté, avec des efficacités de diffraction largement supérieures à l'unité. Les propriétés diffractives des réseaux d'indice et/ou de gain insérés dans un résonateur de Fabry-Pérot amplificateur de longueur supérieure ou égale à l'épaisseur du réseau sont analysées théoriquement et expérimentalement. Un modèle analytique a été élaboré et a permis de montrer l'immense potentiel de tels dispositifs, en terme de sélectivité angulaire et d'efficacité de diffraction, cette dernière pouvant être très largement supérieure à l'unité. Un dispositif expérimental a ensuite été conçu afin de prouver la faisabilité du concept et de valider le modèle analytique. Le milieu non-linéaire intracavité est un cristal de Nd:YVO4. Le réseau est inscrit optiquement par absorption de la figure d'interférence de deux faisceaux d'écriture. La diffraction du signal de lecture est analysée autour de la double résonance de Bragg et de Fabry-Pérot, ainsi qu'à proximité de l'une ou de l'autre résonance séparément, afin de remonter aux propriétés diffractives du réseau. Les résultats expérimentaux sont en bon accord avec les calculs numériques issus du modèle analytique. La comparaison avec le réseau de Bragg hors cavité montre l'amélioration significative apportée par la cavité amplificatrice: l'efficacité de diffraction est augmentée d'un facteur 5000 et la sélectivité angulaire d'un facteur proche de 20. Ces résultats sont très encourageants pour une application de ce type de dispositif au traitement optique de l'information, surtout dans le cas où une très forte sortance est nécessaire.