Design of asymmetrical directional couplers on ridge and strip SOI technology with high-dimensional variation tolerance

[EN] The supermode analysis of asymmetrical directional couplers (ADC) based on SOI technology for strip and ridge structures at 1550 nm is herein reported, targeting to reduce ADC device fabrication requirements. The reported analysis based on supermodes permits us to assess the sensitivity of the ADC coupling efficiency by calculating the index difference between even and odd supermodes. Optimum designs have been found for 100 and 400 nm gaps, respectively, capable of converting and (de) multiplexing both TE0 and TE1 modes taking into account the width, gap, height, and slab thickness variations produced with respect to the nominal design. (C) 2018 Optical Society of AmericaMinisterio de Economia y Competitividad (MINECO) (TEC2015-70858-C2-1-R, RTC-2014-2232-3).García-Rodríguez, D.; Corral, JL.; Llorente, R. (2018). Design of asymmetrical directional couplers on ridge and strip SOI technology with high-dimensional variation tolerance. Optics Letters. 43(11):2491-2494. https://doi.org/10.1364/OL.43.002491S249124944311Essiambre, R.-J., Kramer, G., Winzer, P. J., Foschini, G. J., & Goebel, B. (2010). Capacity Limits of Optical Fiber Networks. Journal of Lightwave Technology, 28(4), 662-701. doi:10.1109/jlt.2009.2039464Richardson, D. J. (2016). New optical fibres for high-capacity optical communications. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 374(2062), 20140441. doi:10.1098/rsta.2014.0441Mizuno, T., Takara, H., Sano, A., & Miyamoto, Y. (2016). Dense Space-Division Multiplexed Transmission Systems Using Multi-Core and Multi-Mode Fiber. Journal of Lightwave Technology, 34(2), 582-592. doi:10.1109/jlt.2015.2482901Winzer, P. J. (2014). Making spatial multiplexing a reality. Nature Photonics, 8(5), 345-348. doi:10.1038/nphoton.2014.58Melati, D., Alippi, A., Annoni, A., Peserico, N., & Melloni, A. (2017). Integrated all-optical MIMO demultiplexer for mode- and wavelength-division-multiplexed transmission. Optics Letters, 42(2), 342. doi:10.1364/ol.42.000342Garcia-Rodriguez, D., Corral, J. L., & Llorente, R. (2017). Mode Conversion for Mode Division Multiplexing at 850 nm in Standard SMF. IEEE Photonics Technology Letters, 29(11), 929-932. doi:10.1109/lpt.2017.2694605Garcia-Rodriguez, D., Corral, J. L., Griol, A., & Llorente, R. (2017). Dimensional variation tolerant mode converter/multiplexer fabricated in SOI technology for two-mode transmission at 1550  nm. Optics Letters, 42(7), 1221. doi:10.1364/ol.42.001221Le, Y.-S., Wang, Z., Li, Z.-Y., Li, Y., Li, Q., Cui, C., & Wu, C.-Q. (2018). Three-mode all-optical (de)multiplexing on a SOI chip. Optics Communications, 406, 173-176. doi:10.1016/j.optcom.2017.04.059Sun, C., Yu, Y., Ye, M., Chen, G., & Zhang, X. (2016). An ultra-low crosstalk and broadband two-mode (de)multiplexer based on adiabatic couplers. Scientific Reports, 6(1). doi:10.1038/srep38494Hanzawa, N., Saitoh, K., Sakamoto, T., Matsui, T., Tsujikawa, K., Uematsu, T., & Yamamoto, F. (2015). PLC-Based Four-Mode Multi/Demultiplexer With LP11 Mode Rotator on One Chip. Journal of Lightwave Technology, 33(6), 1161-1165. doi:10.1109/jlt.2014.2378281Yamashita, Y., Fujisawa, T., Makino, S., Hanzasa, N., Sakamoto, T., Matsui, T., … Saitoh, K. (2017). Design and Fabrication of Broadband PLC-Based Two-Mode Multi/Demultiplexer Using a Wavefront Matching Method. Journal of Lightwave Technology, 35(11), 2252-2258. doi:10.1109/jlt.2016.2641461Zanzi, A., Brimont, A., Griol, A., Sanchis, P., & Marti, J. (2016). Compact and low-loss asymmetrical multimode interference splitter for power monitoring applications. Optics Letters, 41(2), 227. doi:10.1364/ol.41.000227Hanzawa, N., Saitoh, K., Sakamoto, T., Matsui, T., Tsujikawa, K., Koshiba, M., & Yamamoto, F. (2014). Mode multi/demultiplexing with parallel waveguide for mode division multiplexed transmission. Optics Express, 22(24), 29321. doi:10.1364/oe.22.029321Wang, J., He, S., & Dai, D. (2014). On-chip silicon 8-channel hybrid (de)multiplexer enabling simultaneous mode- and polarization-division-multiplexing. Laser & Photonics Reviews, 8(2), L18-L22. doi:10.1002/lpor.201300157Pan, C., & Rahman, B. M. A. (2016). Accurate Analysis of the Mode (de)multiplexer Using Asymmetric Directional Coupler. Journal of Lightwave Technology, 34(9), 2288-2296. doi:10.1109/jlt.2016.2530852Mikkelsen, J. C., Sacher, W. D., & Poon, J. K. S. (2014). Dimensional variation tolerant silicon-on-insulator directional couplers. Optics Express, 22(3), 3145. doi:10.1364/oe.22.003145Xu, K. (2014). Corrections to «On the Design and Optimization of Three-Terminal Light-Emitting Device in Silicon CMOS Technology» [Jul/Aug 14 8201208]. IEEE Journal of Selected Topics in Quantum Electronics, 20(4), 422-422. doi:10.1109/jstqe.2014.2318271Corral, J. L., Garcia-Rodriguez, D., & Llorente, R. (2016). Mode-Selective Couplers for Two-Mode Transmission at 850 nm in Standard SMF. IEEE Photonics Technology Letters, 28(4), 425-428. doi:10.1109/lpt.2015.249708

Mode-selective couplers for two-mode transmission at 850 nm in standard SMF

© 2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.The optimal design of a low-loss fused fiber mode-selective coupler for two-mode fiber transmission in the 850-nm band is presented. The coupler is based on precise phase matching of the propagation constants in each arm of a weakly fused fiber coupler. The designed component permits both mode converter and mode multiplexer/demultiplexer operation, thus enabling modal multiplexing transmission in this band with no additional component. The presented design is evaluated by simulation considering two types of structures, leading to asymmetric and symmetric coupler configurations. Mode converter and mode multiplexer operation is achieved with 93.5% efficiency in the band of 845 855 nm. Mode demultiplexer operation is achieved with an extinction ratio better than 20.4 dB in the same band.This work was supported by the Spanish Ministerio de Economia y Competitividad under Project RTC-2014-2232-3 HIDRASENSE and Project TEC2012-38558-C02-01.Corral, JL.; García Rodríguez, D.; Llorente Sáez, R. (2016). Mode-selective couplers for two-mode transmission at 850 nm in standard SMF. IEEE Photonics Technology Letters. 28(4):425-428. https://doi.org/10.1109/LPT.2015.2497080S42542828

Modal Selectivity at 850 nm employing Standard Single-Mode Couplers: Theory and Experimental Demonstration

[EN] In this paper, we evaluate experimentally and analyze theoretically and by simulation the demultiplexing of LP01 and LP11 modes in a 850 nm few mode optical link when a standard single-mode coupler theoretically designed for 1550 nm operation is used. The simulation analysis indicates a feasible conversion efficiency higher than 98% for the LP01 mode and 100% efficiency for LP11 mode. These results are experimentally validated considering different off-the-shelf optical couplers configured in 99:1, 90:10, 80:20 and 60:40 coupling ratios. Experimental analysis of the optical couplers demonstrate adequate functionality in correspondence with the theoretical analysis, exhibiting a good near-field pattern and modal profile for the LP01 and LP11 modes. The mode purity observed was 98.4% for the LP01 mode, and higher than 90% for the LP11 mode. The 90:10 optical coupler configuration shows best mode purity with the minimal insertion losses.This work was supported by the Ministerio de Economia y Competitividad (MINECO/FEDER), Spain (grant numbers TEC2015-70858-C2-1-R and RTC-2014-2232-3).García-Rodríguez, D.; Morant, M.; Corral, JL.; Llorente, R. (2019). Modal Selectivity at 850 nm employing Standard Single-Mode Couplers: Theory and Experimental Demonstration. Optics Communications. 436:248-252. https://doi.org/10.1016/j.optcom.2018.12.003S24825243

Entangled microwaves as a resource for entangling spatially separate solid-state qubits: Superconducting qubits, nitrogen-vacancy centers, and magnetic molecules

13 págs.; 10 figs.; 2 apps.Quantum correlations present in a broadband two-line squeezed microwave state can induce entanglement in a spatially separated bipartite system consisting of either two single qubits or two-qubit ensembles. By using an appropriate master equation for a bipartite quantum system in contact with two separate but entangled baths, the generating entanglement process in spatially separated quantum systems is thoroughly characterized. Decoherence thermal effects on the entanglement transfer are also discussed. Our results provide evidence that this entanglement transfer by dissipation is feasible, yielding to a steady-state amount of entanglement in the bipartite quantum system which can be optimized for a wide range of realistic physical systems that include state-of-the-art experiments with nitrogen-vacancy centers in diamond, superconducting qubits, or even magnetic molecules embedded in a crystalline matrix. ©2016 American Physical SocietyA.V.G., F.J.R., and L.Q. acknowledge financial support from Facultad de Ciencias at UniAndes-2015 Project “Transfer of Correlations from Non-classically Correlated Reservoirs to Solid State Systems” and Project “Quantum Control of Non-equilibrium Hybrid Systems-Part II,” UniAndes-2015. J.J.G.R. acknowledges support from Spanish Mineco Project No. FIS2012-33022, from EU FP7 Project PROMISCE, from CAM Research Network QUITEMAD+.Peer Reviewe

Influence of ships emissions in the ultrafine particles pollution in an urban coastal air

Comunicación presentada en: V Reunión Española de Ciencia y Tecnología de Aerosoles – RECTA 2011 celebrada del 27 al 29 de junio de 2011 en CIEMAT, Madrid.Experimental data (2008-2009) of particle number (N≥2.5 nm diameter) and black carbon (BC) concen-trations and of gaseous pollutants recorded in the city of Santa Cruz de Tenerife was analyzed in order to asses the impact of ship emissions on the ultrafine particle (UFP) concentrations in coastal urban areas. The observed relationship between N and the other air pollutants, allowed segregating the contribu-tion of vehicle exhaust and of ship emissions to the UFP con-centrations in the urban ambient air. The influence of fresh vehicle exhaus

Integrated analysis of mismatch repair system in malignant astrocytomas

This is an open-access article distributed under the terms of the Creative Commons Attribution License.-- et al.Malignant astrocytomas are the most aggressive primary brain tumors with a poor prognosis despite optimal treatment. Dysfunction of mismatch repair (MMR) system accelerates the accumulation of mutations throughout the genome causing uncontrolled cell growth. The aim of this study was to characterize the MMR system defects that could be involved in malignant astrocytoma pathogenesis. We analyzed protein expression and promoter methylation of MLH1, MSH2 and MSH6 as well as microsatellite instability (MSI) and MMR gene mutations in a set of 96 low- and high-grade astrocytomas. Forty-one astrocytomas failed to express at least one MMR protein. Loss of MSH2 expression was more frequent in low-grade astrocytomas. Loss of MLH1 expression was associated with MLH1 promoter hypermethylation and MLH1 -93G>A promoter polymorphism. However, MSI was not related with MMR protein expression and only 5% of tumors were MSI-High. Furthermore, the incidence of tumors carrying germline mutations in MMR genes was low and only one glioblastoma was associated with Lynch syndrome. Interestingly, survival analysis identified that tumors lacking MSH6 expression presented longer overall survival in high-grade astrocytoma patients treated only with radiotherapy while MSH6 expression did not modify the prognosis of those patients treated with both radiotherapy and chemotherapy. Our findings suggest that MMR system alterations are a frequent event in malignant astrocytomas and might help to define a subgroup of patients with different outcome.This work was supported by Fondo de Investigación Sanitaria (FIS PI 10/00219), Instituto de Estudios de Ciencias de la Salud de Castilla y León IECSCYL and Junta de Castilla y León y Fondo Social Europeo (Orden EDU/330/2008).Peer Reviewe

Stochastic unit commitment in microgrids: Influence of the load forecasting error and the availability of energy storage

A Stochastic Model for the Unit Commitment (SUC) problem of a hybrid microgrid for a short period of 24 h is presented. The microgrid considered in the problem is composed of a wind turbine (WT), a photovoltaic plant (PV), a diesel generator (DE), a microturbine (MT) and a Battery Energy Storage System (BESS). The problem is addressed in three stages. First, based on the historical data of the demanded power in the microgrid, an ARMA model is used to obtain the demand prediction. Second, the 24-h-ahead SUC problem is solved, based on generators’ constraints, renewable generation and demand forecast and the statistical distribution of the error in the demand estimation. In this problem, a spinning reserve of the dispatchable units is considered, able to cover the uncertainties in the demand estimation. In the third stage, once the SUC problem has been solved, a case study is established in real time, in which the demand estimation error in every moment is known. Therefore, the objective of this stage is to select the spinning reserve of the units in an optimal way to minimize the cost in the microgrid operation

Resultados de un programa de ahorro de sangre en prótesis de rodilla unilateral

La implantación de una prótesis de rodilla es un procedimiento que frecuentemente requiere reposición hemática en el postoperatorio inmediato. Entre las alternativas a la sangre alogénica, se ha propuesto la autodonación como una opción segura y efectiva; sin embargo, este procedimiento no está exento de controversia dada la anemia preoperatorio que supone para el paciente y el elevado coste de las unidades no utilizadas y, por tanto, desechadas. Se presentan los resultados obtenidos a lo largo de los últimos tres años con el uso no restrictivo de un programa de autotransfusión en pacientes en quienes se implantó una prótesis de rodilla unilateral. Las cifras obtenidas muestran una ligera reducción en la tasa de transfusión alogénica, pero con una eficiencia baja. Se plantean otras alternativas de reposición hemática y el perfil de pacientes que sería candidatos a seguir en un programa de autodonación.Total knee replacement is a procedure that frequently need postoperative blood transfusion. Instead of allogeneic blood, predeposit autologous transfusion has been proposed as a safe and efficient choice; nevertheless, this procedure is not free of debate due to the anaemia caused to the patients and the high number of no-used, and lost, units. We report the results of a no restrictive program of blood autologous transfusion in patients having a knee replace- ment, in the period between 2001 to 2003. The numbers show a slight decrease in the rate of allogeneic blood transfusion; nonetheless, with a short efectivenuess. We analyse other alternatives for blood transfusion and in what patients this procedure should be done

Comment on 'Distinct clinical outcomes of two CIMP-positive colorectal cancer subtypes based on a revised CIMP classification system'

This work was funded by Projects PI13/01741, PI13/01273, PI16/01920 and PI16/01650 from the Spanish Ministry of Health and Consumer Affairs and FEDER, and Mutua Madrileña Foundation (2012-0036), and was approved by the Ethics Committee of our Institution.Peer Reviewe