Non conventional optical systems
Dissolved methane optical sensor :
Test structure of the CH4 sensor made of side-by-side diffractive optical waveguides (grating pitch of 1.28µm).
Methane (CH4) is a recognized source of alternative energy and contributes to at least 20% of greenhouse gases. Oceans store considerable amounts of this gas and innovative sensors need to be developped to be able to study its geographic distribution. In collaboration with two other laboratories (GET Toulouse and ENS Lyon), we proposed an integrated optic sensor which, through a simple angular measurement, allows the detection of time-varying minute concentrations of methane dissolved in sea water. The sensor exploits a diffractive optical waveguide coated with a methane-sensitive polymer layer. This device is designed to operate under high pressures and in high-temperature-gradient environments (P ~ 450 bars, T ~ 0 à 400°C) to meet the requirements of methane exploration near the ocean floor and more specifically close to hydrothermal sources.
Related publications :
- Emerging technologies for in-situ dissolved methane measurements : S.AOUBA, C.BOULART, O.CARRAZ, P.ARGUEL, M.AUFRAY, P.BEHRA, O.BERNAL, A.CASTILLO, M.CATTOEN, V.CHAVAGNAC, B.DUBREUIL, J.P.DUTASTA, F.LOZES-DUPUY, P.GISQUET, HC.SEAT, Environmental Sensors 2012 du 23 septembre au 28 septembre 2012, Anglet (France), Septembre 2012, 1p. (Résumé) , N° 12843
- Deep sea observatory: a need of in situ dissolved methane sensor : V.CHAVAGNAC, C.BOULART, O.CARRAZ, HC.SEAT, M.CATTOEN, T.BOSCH, S.AOUBA, P.ARGUEL, F.LOZES-DUPUY, B.DUBREUIL, M.AUFRAY, P.BEHRA, Workshop MAISOE - RTRA - STAE 2011 du 21 novembre au 23 novembre 2011, Aspet (France), Novembre 2011, 1p. (Résumé) , N° 11882
Silicon-based monolithic micro-interferometer :
Schematic drawing of the micro-interferometer made of a grating and a photodiode. (Insert : Picture of a fully-operational device constituted of a 1µm-pitch grating integrated on top of a photodiode).
Integrating both optical and electronic functionalities on a single chip enables the fabrication of compact and robust systems which, in turn, open new opportunities or applications. In this context, we have experimentally demonstrated a micro-interferometer which monolithically integrates the beam-combining and photo-detection functions and which can be made using standard CMOS technology. The device enables the measurement of free-space optical phase difference, a parameter used in many sensing applications such as thermal expansion, concentration, pressure or displacement sensing and monitoring. It also paves the way towards the development of innovative equipments including optical data storage, 3-dimensional imaging, digital holography, or wavefront analysis systems. Finally, using a judiciously designed array, the amplitude, phase and polarisation content of a free-space-propagating optical beam could be simultaneously measured.
Related publications :
- A monolithic optical phase-shift sensor on silicon : P.ARGUEL, J.VALENTIN, S.FOURMENT, F.LOZES-DUPUY, G.SARRABAYROUSE, S.BONNEFONT, Y.JOURLIN, S.REYNAUD, N.DESTOUCHES, A.TISHCHENKO, J.JAY, IEEE Sensors Journal, Vol.5, N°6, pp.1305-1309, Décembre 2005 , N° 05402
- Diffraction grating for an integrated CMOS-compatible optical phase-shift sensor : P.ARGUEL, J.VALENTIN, O.BOUCHARD, S.BONNEFONT, F.LOZES-DUPUY,
IEEE Sensors Journal, Vol.7, N°12, pp.1757-1758, Décembre 2007 , N° 07745
- Dispositif de détection d'interférences monolithique intégré : P.ARGUEL, F.LOZES-DUPUY, G.SARRABAYROUSE, O.BOUCHARD,
Brevet : WO 2008074939 (A1), 16 Janvier 2009 , N° 09815
Polarization independent guided mode resonant filters (GMRFs):
2D map of the reflection coefficient of polarization independent GMRF as a function of both wavelength and polariztion state of the incident beam (angle of incidence 12°).
To address the ever increasing requirements of sattelite observation and, in collaboration with CNES (Toulouse) and the Institut Fresnel (Marseille), we investigate a novel generation of wavelength-tunable high-spectral-selectivity and polarisation-independent filters. An innovative filter which combines two waveguides and two crossed 1D gratings has been proposed and experimentally demonstrated. In the near infrared and under oblique incidence, such reflective filter has been shown to provide a reflection with widely tunable (> 100 nm) central wavelength, narrow (1nm , quality factor of 2300) bandwidth and (within 3%) polarisation-independent response. This study is being furthered as a dedicated collaborative research project with CNES.
Related publications :
- Tunable, polarization independent, narrow-band filtering with one-dimensional crossed resonant gratings : A.L.FEHREMBACH, K.CHAN SHIN YU, A.MONMAYRANT, P.ARGUEL, A.SENTENAC, O.GAUTHIER-LAFAYE, Optics Letters, Vol.36, N°9, pp.1662-1664, Mai 2011 , N° 11226
- Filtre optique à réseau résonnant insensible à la polarisation accordable en fonction de l'angle d'incidence : A.MONMAYRANT, O.GAUTHIER-LAFAYE, K.CHAN SHIN YU, A.L.FEHREMBACH, A.SENTENAC, P.ARGUEL, J.LOESEL, Brevet : FR 2970088 (B1); Egalement publié en tant que : EP 2661649 (A1) WO 2012093119 (A1) , Août 2013, 13p. , N° 13730
Wavelength selection and stabilisation of laser diodes using nano-photonic filters:Superimposed spectra of a extended-cavity laser diode using 5 different CRIGFs of varying pitch (from 504 to 524 nm).
Within a DGA and CNES-funded project, the use of guided mode resonant filters (GMRFs) as wavelength-selective element of extended-cavity laser diodes is being studied. The GMRF simultaneously serves as an end cavity mirror and a wavelength-selective element, thereby realising a functional integration exploiting nano-photonic components. The objective is to exploit the unusual properties of the reflective spectral selection afforded by these GMRFs. Using such filters, wavelength-stabilised laser diodes with short (down to sub-cm length) extended cavity should be achievable, making these laser systems more practical and reliable for on-board applications. This work is carried out in close collaboration with the OSE team. In a first instance, we investigated the use of these filters in the collimated beam section of a Littrow-type cavity. Purposely-designed wavelength-selective mirrors with larger angular tolerance were also studied in parallel to permit the use of cat's eye extended cavity configurations which are known to offer better performance and greater robustness (tolerance) than Littrow setups. To that extent, we have develop a novel concept based on "Cavity Integrated Grating Filters" (CRIGFs) which can provide high-reflectivty high-qualty-factor spectral response with large angular acceptance. These reflectors were subsequently introduced in an much simpler extended cavity laser diode setup constituted of only three elements. The resulting laser performance of the demonstrator led to the renewal of the research contract with CNES to study the potential of these sources for space applications such as Pharao.
Related publications :
- X. Buet, E. Daran, D. Belharet, F. Lozes-Dupuy, A. Monmayrant, and O. Gauthier-Lafaye , High angular tolerance and reflectivity with narrow bandwidth cavity-resonator-integrated guided-mode resonance filter, Opt. Express (20), pp9322-9327 (2012).
- X. Buet, A. Guelmami, A. Monmayran, S. Calvez, C. Tourte, F. Lozes-Dupuy and O. Gauthier-Lafaye, Wavelength-stabilised external-cavity laser diode using cavity resonator integrated guided mode filter Electronics Letters, Volume 48, issue25, 6 December 2012, p. 1619 – 1621