Análisis y caracterización de guías corrugadas de onda lenta para aplicaciones de modulación electro-óptica en silicio

[ES] El objetivo de este trabajo es demostrar experimentalmente el funcionamiento pasivo de estructuras de onda lenta. Se han caracterizado guías corrugadas en obleas SOI con el fin de validar sus características de onda lenta teóricamente alcanzables, de las cuales se espera que mejoren el funcionamiento de un modulador MZI[EN] The objective of this report is to demonstrate the passive performance of the slow-wave structures. Corrugated waveguides are characterized on SOI wafer in order to validate their theoretically achievable slow wave features, expected to improve the performance of a MZI modulator.Gutiérrez Campo, AM. (2010). Análisis y caracterización de guías corrugadas de onda lenta para aplicaciones de modulación electro-óptica en silicio. http://hdl.handle.net/10251/27276.Archivo delegad

Indicios y certezas: "Mulieres religiosae" en Zaragoza (siglos XIII-XVI)

This article deals with the so-far-unknown phenomenon of the mulieres religiosae in the Kingdom of Aragon from the 13th through the 16th century. Special attention is paid to the names these women were given, such as beguina (beguine), beata, emparedada ( cellite), reclusa and hospitalera. After that, we focus on the activities the mulieres religiosae developed -which were the Works of Mercy- and on the rafe these women played in redistribuiting goods and money. Finally, due to the multiple signs of respect and consideration showed by our sources, we come to the conclusion that the mulieres religiosae were deeply appreciated by their society, despite of the angry words of some authors against them.This article deals with the so-far-unknown phenomenon of the mulieres religiosae in the Kingdom of Aragon from the 13th through the 16th century. Special attention is paid to the names these women were given, such as beguina (beguine), beata, emparedada ( cellite), reclusa and hospitalera. After that, we focus on the activities the mulieres religiosae developed -which were the Works of Mercy- and on the rafe these women played in redistribuiting goods and money. Finally, due to the multiple signs of respect and consideration showed by our sources, we come to the conclusion that the mulieres religiosae were deeply appreciated by their society, despite of the angry words of some authors against them

El lenguaje de las predicciones meteorológicas. De los boletines y los productos a los medios de comunicación social

Ponencia presentada en: VI Simposio Nacional de Predicción, celebrado en los servicios centrales de AEMET, en Madrid, del 17 al 19 de septiembre de 2018.En esta ponencia proponemos una mirada sobre nuestros productos y nuestro léxico desde el punto de vista de la utilidad y la comprensibilidad para el usuario. Es decir, queremos hacer una revisión de la forma, más que del contenido, de nuestras predicciones; nos fijaremos en algunos de los productos o conceptos que más habitualmente suscitan dudas, controversias o gran expectación; pondremos algunos ejemplos de cómo manejamos en los medios y las redes sociales estas cuestiones, y haremos algunas propuestas para mejorar la comprensión de nuestras predicciones

High performace silicon 2x2 optical switch based on a thermo-optically tunable multimode interference coupler and efficient electrodes

Optical switches based on tunable multimode interference (MMI) couplers can simultaneously reduce the footprint and increase the tolerance against fabrication deviations. Here, a compact 2x2 silicon switch based on a thermo-optically tunable MMI structure with a footprint of only 0.005mm2 is proposed and demonstrated. The MMI structure has been optimized using a silica trench acting as a thermal isolator without introducing any substantial loss penalty or crosstalk degradation. Furthermore, the electrodes performance have significantly been improved via engineering the heater geometry and using two metallization steps. Thereby, a drastic power consumption reduction of around 90% has been demonstrated yielding to values as low as 24.9 mW. Furthermore, very fast switching times of only 1.19 μs have also been achieved.Financial support from LEOMIS TEC2012-38540 and PROMETEOII/2014/034 projects is acknowledged. Alvaro Rosa also acknowledges the Spanish Ministry of Economy and Competitiveness for funding his grant. The authors also would like to thank the Electronic Microscopy Department at UPV for taking the SEM images.Rosa Escutia, Á.; Gutiérrez Campo, AM.; Brimont, ACJ.; Griol Barres, A.; Sanchis Kilders, P. (2016). High performace silicon 2x2 optical switch based on a thermo-optically tunable multimode interference coupler and efficient electrodes. Optics Express. 24(1):191-198. https://doi.org/10.1364/OE.24.000191S191198241Subbaraman, H., Xu, X., Hosseini, A., Zhang, X., Zhang, Y., Kwong, D., & Chen, R. T. (2015). Recent advances in silicon-based passive and active optical interconnects. Optics Express, 23(3), 2487. doi:10.1364/oe.23.002487Nikolova, D., Rumley, S., Calhoun, D., Li, Q., Hendry, R., Samadi, P., & Bergman, K. (2015). Scaling silicon photonic switch fabrics for data center interconnection networks. Optics Express, 23(2), 1159. doi:10.1364/oe.23.001159Dong, P., Preble, S. F., & Lipson, M. (2007). All-optical compact silicon comb switch. Optics Express, 15(15), 9600. doi:10.1364/oe.15.009600Biberman, A., Lira, H. L. R., Padmaraju, K., Ophir, N., Chan, J., Lipson, M., & Bergman, K. (2011). Broadband Silicon Photonic Electrooptic Switch for Photonic Interconnection Networks. IEEE Photonics Technology Letters, 23(8), 504-506. doi:10.1109/lpt.2011.2112763Li, G., Zheng, X., Yao, J., Thacker, H., Shubin, I., Luo, Y., … Krishnamoorthy, A. V. (2011). 25Gb/s 1V-driving CMOS ring modulator with integrated thermal tuning. Optics Express, 19(21), 20435. doi:10.1364/oe.19.020435Densmore, A., Janz, S., Ma, R., Schmid, J. H., Xu, D.-X., Delâge, A., … Cheben, P. (2009). Compact and low power thermo-optic switch using folded silicon waveguides. Optics Express, 17(13), 10457. doi:10.1364/oe.17.010457Van Campenhout, J., Green, W. M., Assefa, S., & Vlasov, Y. A. (2009). Low-power, 2×2 silicon electro-optic switch with 110-nm bandwidth for broadband reconfigurable optical networks. Optics Express, 17(26), 24020. doi:10.1364/oe.17.024020Dong, P., Liao, S., Liang, H., Shafiiha, R., Feng, D., Li, G., … Asghari, M. (2010). Submilliwatt, ultrafast and broadband electro-optic silicon switches. Optics Express, 18(24), 25225. doi:10.1364/oe.18.025225Sun, P., & Reano, R. M. (2010). Submilliwatt thermo-optic switches using free-standing silicon-on-insulator strip waveguides. Optics Express, 18(8), 8406. doi:10.1364/oe.18.008406Watts, M. R., Sun, J., DeRose, C., Trotter, D. C., Young, R. W., & Nielson, G. N. (2013). Adiabatic thermo-optic Mach–Zehnder switch. Optics Letters, 38(5), 733. doi:10.1364/ol.38.000733Harris, N. C., Ma, Y., Mower, J., Baehr-Jones, T., Englund, D., Hochberg, M., & Galland, C. (2014). Efficient, compact and low loss thermo-optic phase shifter in silicon. Optics Express, 22(9), 10487. doi:10.1364/oe.22.010487Suzuki, K., Cong, G., Tanizawa, K., Kim, S.-H., Ikeda, K., Namiki, S., & Kawashima, H. (2015). Ultra-high-extinction-ratio 2 × 2 silicon optical switch with variable splitter. Optics Express, 23(7), 9086. doi:10.1364/oe.23.009086Sanchez, L., Griol, A., Lechago, S., Brimont, A., & Sanchis, P. (2015). Low-Power Operation in a Silicon Switch Based on an Asymmetric Mach–Zehnder Interferometer. IEEE Photonics Journal, 7(2), 1-8. doi:10.1109/jphot.2015.2407317Besse, P. A., Bachmann, M., Melchior, H., Soldano, L. B., & Smit, M. K. (1994). Optical bandwidth and fabrication tolerances of multimode interference couplers. Journal of Lightwave Technology, 12(6), 1004-1009. doi:10.1109/50.296191Soldano, L. B., & Pennings, E. C. M. (1995). Optical multi-mode interference devices based on self-imaging: principles and applications. Journal of Lightwave Technology, 13(4), 615-627. doi:10.1109/50.372474Leuthold, J., & Joyner, C. W. (2001). Multimode interference couplers with tunable power splitting ratios. Journal of Lightwave Technology, 19(5), 700-707. doi:10.1109/50.923483Fan Wang, Jianyi Yang, Limei Chen, Xiaoqing Jiang, & Minghua Wang. (2006). Optical switch based on multimode interference coupler. IEEE Photonics Technology Letters, 18(2), 421-423. doi:10.1109/lpt.2005.86320

Analysis and design optimization of a hybrid VO2/Silicon 2x2 microring switch

The metal-to-insulator transition (MIT) property of vanadium dioxide (VO2) has been recently used in several application fields like plasmonics, sensing, metamaterials and optical modulation. Due to the MIT nature, VO2 allows a huge change in its complex refractive index that can be electro-optically controlled. In this work, the analysis and design optimization of a 2x2 microring switch based on a hybrid VO2/silicon waveguide structure is addressed. Switching is achieved by exploiting the change in both absorption loss and phase shift that occurs in the VO2 when changing from the insulating to the metallic state. The device is optimized to minimize insertion losses and crosstalk. An active length of only 2.8µm is required to achieve a data throughput rate higher than 500Gbps at a single optical wavelength.This work was also supported by LEOMIS (TEC2012-38540) and NANOMET PLUS-Conselleria d'Educacio, Cultura i Esport (PROMETEOII/2014/034). The work of L. Sanchez was supported by the Generalitat Valenciana in the context of the VALi+d program.Sánchez Diana, LD.; Lechago-Buendia, S.; Gutiérrez Campo, AM.; Sanchis Kilders, P. (2016). Analysis and design optimization of a hybrid VO2/Silicon 2x2 microring switch. IEEE Photonics Journal. 8(2):1-9. https://doi.org/10.1109/JPHOT.2016.2551463S198

Electro-Optical Modulation Based on Pockels Effect in BaTiO3 With a Multi-Domain Structure

[EN] The influence of an in-plane multi-domain structure in BaTiO3 films grown on SrTiO3/Si buffers for highly efficient electro-optic modulation has been analyzed. The modulation performance can be significantly enhanced by rotating a certain angle, the optical waveguide, with respect to the BaTiO3 crystallographic axes. A robust electro-optical performance against variations in the domain structure as well as the lowest V-pi voltage can be achieved by using the rotation angles between 35 degrees and 55 degrees. Our calculations show that Vp voltages below 1.7 V for a modulation length of 2 mm can be obtained by means of a CMOS compatible hybrid silicon/BaTiO3 waveguide structure.This work was supported by the European Commission under Grant FP7-ICT-2013-11-619456 SITOGA. The work of P. Sanchis was supported in part by GVA under Grant PROMETEOII/2014/034 and in part by the Ministerio de Economia y Competitividad under Grant TEC2012-38540 LEOMIS.Castera, P.; Gutiérrez Campo, AM.; Tulli, D.; Cueff, S.; Orobtchouk, R.; Rojo Romeo, P.; Saint-Girons, G.... (2016). Electro-Optical Modulation Based on Pockels Effect in BaTiO3 With a Multi-Domain Structure. IEEE Photonics Technology Letters. 28(9):990-993. https://doi.org/10.1109/LPT.2016.252250999099328

A CMOS Compatible Silicon-on-Insulator Polarization Rotator Based on Symmetry Breaking of the Waveguide Cross Section

[EN] A polarization rotator in silicon-on-insulator technology based on breaking the symmetry of the waveguide cross section is reported. The 25-mu m-long device is designed to be integrated with standard grating couplers without the need for extra fabrication steps. Hence, fabrication is carried out by a 2-etch-step complementary metal-oxide-semiconductor compatible process using 193-nm deep ultraviolet lithography. A polarization conversion efficiency of more than -0.85 dB with insertion losses ranging from -1 to -2.5 dB over a wavelength range of 30 nm is demonstrated. © 1989-2012 IEEEThis work was supported by the European Commission under Project HELIOS (pHotonics Electronics functional Integration on CMOS), FP7-224312, TEC2008-06333 SINADEC and PROMETEO-2010-087 R&D Excellency Program (NANOMET).Aamer, M.; Gutiérrez Campo, AM.; Brimont, ACJ.; Vermeulen, D.; Roelkens, G.; Fedeli, J.; Håkansson, OA.... (2012). A CMOS Compatible Silicon-on-Insulator Polarization Rotator Based on Symmetry Breaking of the Waveguide Cross Section. IEEE Photonics Technology Letters. 24(22):2031-2034. https://doi.org/10.1109/LPT.2012.2218593S20312034242

Analytical model for calculating the nonlinear distortion in silicon-based electro-optic Mach-Zehnder modulators

[EN] In this study, an analytical model for calculating the nonlinear harmonic/intermodulation distortion for RF signals in silicon-based electro-optic modulators is investigated by considering the nonlinearity on the effective index change curve with the operation point and the device structure simultaneously. Distortion expressions are obtained and theoretical results are presented showing that optimal modulator parameters can be found to linearize it. Moreover, the harmonic distortion of a 1 mm silicon-based asymmetric MZI is RF characterized and used to corroborate the theoretical results. Based on the present model, the nonlinear distortion in terms of bias voltage or operating wavelength is calculated and validated by comparing with the experimental data, showing a good agreement between measurements and theory. Analog photonic link quality parameter like carrier-todistortion is one of the parameters that can be found with that model. Finally, the modulation depth is measured to assure that no over-modulation is produced.This work was supported by the funding from the European Commission under project HELIOS (pHotonics Electronics functional Integration on CMOS), FP7-224312. The work of P. Sanchis and J.-M. Fedeli was supported by the funding funding from TEC2012-38540 LEOMIS, TEC2008-06333 SINADEC, and PROMETEO-2010-087. The work of F. Y. Gardes, D. J. Thomson and G. T. Reed was supported by funding received from the UK EPSRC funding body under the grant "UK Silicon Photonics."Gutiérrez Campo, AM.; Brimont, ACJ.; Herrera Llorente, J.; Aamer, M.; Thomson, DJ.; Gardes, FY.; Reed, GT.... (2013). Analytical model for calculating the nonlinear distortion in silicon-based electro-optic Mach-Zehnder modulators. Journal of Lightwave Technology. 31(23):3603-3612. https://doi.org/10.1109/JLT.2013.2286838S36033612312

Compact focusing grating couplers for silicon horizontal slot waveguides

In this Letter, we present the design, simulation (2D and 3D), fabrication, and experimental characterization of compact and fully etched focusing gratings for a horizontal slot waveguide based on a silicon nitride layer sandwiched between amorphous silicon and a silicon-on-insulator. The measured coupling losses are about 4 dB with a 3 dB bandwidth of 38 nm. The fully etched configuration allows the fabrication in a single lithography step.Ministerio de Economia y Competitividad (MINECO) (TEC2012-38540-C02-02, TEC2016-76849-C2-2-R); Generalitat Valenciana (NANOMET PLUS -PROMETEOII/2014/034).Larrea-Luzuriaga, RA.; Gutiérrez Campo, AM.; Hurtado Montañés, J.; Ramirez, JM.; Garrido, B.; Sanchis Kilders, P. (2017). Compact focusing grating couplers for silicon horizontal slot waveguides. Optics Letters. 42(3):490-493. https://doi.org/10.1364/OL.42.000490S49049342

Barium titanate (BaTiO3) RF characterization for application in electro-optic modulators

[EN] Barium titanate (BaTiO3 or BTO) is currently one of the most promising ferroelectric materials for enabling Pockels modulation that is compatible with silicon photonic circuits. The relative permittivity of BTO has been characterized in thin films deposited on a silicon-on-insulator (SOI) substrate. High values between 800 and 1600 have been estimated at 20 GHz. Furthermore, no substantial difference has been obtained by using BTO grown by molecular beam epitaxy and sputtering. The obtained permittivity has been used to properly design the RF electrodes for high-speed modulation in hybrid BTO/Si devices. Electrodes have been fabricated and the possibility of achieving modulation bandwidths up to 40 GHz has been demonstrated. The bandwidth is limited by the microwave propagation losses and, in this case, different losses have been measured depending on the BTO growth process.Financial support from European Commission under project FP7-ICT-2013-11-619456 SITOGA, and from TEC2016-76849-C2-2-R and NANOMET Conselleria de Educació, Cultura i Esport -PROMETEOII/2014 034 are acknowledged. Álvaro Rosa also acknowledges the Spanish Ministry of Economy and Competitiveness for funding his grant.Rosa Escutia, Á.; Tulli, D.; Castera-Molada, P.; Gutiérrez Campo, AM.; Griol Barres, A.; Baquero Escudero, M.; Vilquin, B.... (2017). Barium titanate (BaTiO3) RF characterization for application in electro-optic modulators. Optical Materials Express. 7(12):4328-4336. https://doi.org/10.1364/OME.7.004328S43284336712Hennings, D. (1987). Barium titanate based ceramic materials for dielectric use. International Journal of High Technology Ceramics, 3(2), 91-111. doi:10.1016/0267-3762(87)90031-2Sengupta, L., & Sengupta, S. (1997). Novel ferroelectric materials for phased array antennas. IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 44(4), 792-797. doi:10.1109/58.655193De Flaviis, F., Alexopoulos, N. G., & Stafsudd, O. M. (1997). Planar microwave integrated phase-shifter design with high purity ferroelectric material. IEEE Transactions on Microwave Theory and Techniques, 45(6), 963-969. doi:10.1109/22.588610Zgonik, M., Bernasconi, P., Duelli, M., Schlesser, R., Günter, P., Garrett, M. H., … Wu, X. (1994). Dielectric, elastic, piezoelectric, electro-optic, and elasto-optic tensors ofBaTiO3crystals. Physical Review B, 50(9), 5941-5949. doi:10.1103/physrevb.50.5941Reed, G. T., Mashanovich, G., Gardes, F. Y., & Thomson, D. J. (2010). Silicon optical modulators. Nature Photonics, 4(8), 518-526. doi:10.1038/nphoton.2010.179Petraru, A., Schubert, J., Schmid, M., & Buchal, C. (2002). Ferroelectric BaTiO3 thin-film optical waveguide modulators. Applied Physics Letters, 81(8), 1375-1377. doi:10.1063/1.1498151Tang, P., Towner, D. J., Hamano, T., Meier, A. L., & Wessels, B. W. (2004). Electrooptic modulation up to 40 GHz in a barium titanate thin film waveguide modulator. Optics Express, 12(24), 5962. doi:10.1364/opex.12.005962Tang, P., Meier, A. L., Towner, D. J., & Wessels, B. W. (2005). BaTiO_3 thin-film waveguide modulator with a low voltage–length product at near-infrared wavelengths of 098 and 155 µm. Optics Letters, 30(3), 254. doi:10.1364/ol.30.000254Dicken, M. J., Sweatlock, L. A., Pacifici, D., Lezec, H. J., Bhattacharya, K., & Atwater, H. A. (2008). Electrooptic Modulation in Thin Film Barium Titanate Plasmonic Interferometers. Nano Letters, 8(11), 4048-4052. doi:10.1021/nl802981qGirouard, P., Liu, Z., Chen, P., Jeong, Y. K., Tu, Y., Ho, S.-T., & Wessels, B. W. (2016). Enhancement of the pockels effect in photonic crystal modulators through slow light. Optics Letters, 41(23), 5531. doi:10.1364/ol.41.005531Abel, S., Stöferle, T., Marchiori, C., Rossel, C., Rossell, M. D., Erni, R., … Fompeyrine, J. (2013). A strong electro-optically active lead-free ferroelectric integrated on silicon. Nature Communications, 4(1). doi:10.1038/ncomms2695Xiong, C., Pernice, W. H. P., Ngai, J. H., Reiner, J. W., Kumah, D., Walker, F. J., … Tang, H. X. (2014). Active Silicon Integrated Nanophotonics: Ferroelectric BaTiO3 Devices. Nano Letters, 14(3), 1419-1425. doi:10.1021/nl404513pAbel, S., Stoferle, T., Marchiori, C., Caimi, D., Czornomaz, L., Stuckelberger, M., … Fompeyrine, J. (2016). A Hybrid Barium Titanate–Silicon Photonics Platform for Ultraefficient Electro-Optic Tuning. Journal of Lightwave Technology, 34(8), 1688-1693. doi:10.1109/jlt.2015.2510282Eltes, F., Caimi, D., Fallegger, F., Sousa, M., O’Connor, E., Rossell, M. D., … Abel, S. (2016). Low-Loss BaTiO3–Si Waveguides for Nonlinear Integrated Photonics. ACS Photonics, 3(9), 1698-1703. doi:10.1021/acsphotonics.6b00350Hsu, M.-H. M., Marinelli, A., Merckling, C., Pantouvaki, M., Van Campenhout, J., Absil, P., & Van Thourhout, D. (2017). Orientation-dependent electro-optical response of BaTiO_3 on SrTiO_3-buffered Si(001) studied via spectroscopic ellipsometry. Optical Materials Express, 7(6), 2030. doi:10.1364/ome.7.002030Rabiei, P., Ma, J., Khan, S., Chiles, J., & Fathpour, S. (2013). Heterogeneous lithium niobate photonics on silicon substrates. Optics Express, 21(21), 25573. doi:10.1364/oe.21.025573Pernice, W. H. P., Xiong, C., Walker, F. J., & Tang, H. X. (2014). Design of a Silicon Integrated Electro-Optic Modulator Using Ferroelectric BaTiO3 Films. IEEE Photonics Technology Letters, 26(13), 1344-1347. doi:10.1109/lpt.2014.2322501Hu, X., Cueff, S., Romeo, P. R., & Orobtchouk, R. (2015). Modeling the anisotropic electro-optic interaction in hybrid silicon-ferroelectric optical modulator. Optics Express, 23(2), 1699. doi:10.1364/oe.23.001699Castera, P., Tulli, D., Gutierrez, A. M., & Sanchis, P. (2015). Influence of BaTiO_3 ferroelectric orientation for electro-optic modulation on silicon. Optics Express, 23(12), 15332. doi:10.1364/oe.23.015332Castera, P., Gutierrez, A. M., Tulli, D., Cueff, S., Orobtchouk, R., Rojo Romeo, P., … Sanchis, P. (2016). Electro-Optical Modulation Based on Pockels Effect in BaTiO3With a Multi-Domain Structure. IEEE Photonics Technology Letters, 28(9), 990-993. doi:10.1109/lpt.2016.2522509Salama, C. A. T., & Siciunas, E. (1972). Characteristics of rf Sputtered Barium Titanate Films on Silicon. Journal of Vacuum Science and Technology, 9(1), 91-96. doi:10.1116/1.1316695Hayashi, T., Oji, N., & Maiwa, H. (1994). Film Thickness Dependence of Dielectric Properties ofBaTiO3Thin Films Prepared by Sol-Gel Method. Japanese Journal of Applied Physics, 33(Part 1, No. 9B), 5277-5280. doi:10.1143/jjap.33.5277Hamano, T., Towner, D. J., & Wessels, B. W. (2003). Relative dielectric constant of epitaxial BaTiO3 thin films in the GHz frequency range. Applied Physics Letters, 83(25), 5274-5276. doi:10.1063/1.1635967McKee, R. A., Walker, F. J., Conner, J. R., Specht, E. D., & Zelmon, D. E. (1991). Molecular beam epitaxy growth of epitaxial barium silicide, barium oxide, and barium titanate on silicon. Applied Physics Letters, 59(7), 782-784. doi:10.1063/1.105341Janezic, M. D., & Jargon, J. A. (1999). Complex permittivity determination from propagation constant measurements. IEEE Microwave and Guided Wave Letters, 9(2), 76-78. doi:10.1109/75.755052Engen, G. F., & Hoer, C. A. (1979). Thru-Reflect-Line: An Improved Technique for Calibrating the Dual Six-Port Automatic Network Analyzer. IEEE Transactions on Microwave Theory and Techniques, 27(12), 987-993. doi:10.1109/tmtt.1979.1129778Alferness, R. C. (1982). Waveguide Electrooptic Modulators. 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