Thin-film coated single-mode–multimode–single-mode (SMS) structures have been analyzed both theoretically and experimentally with the aim of detecting different refractive indices. By adequate selection of the thickness of the thin film and of the diameter of the multimode segment in the SMS structure, a seven-fold improvement can be obtained in the sensitivity of the device to the surrounding medium refractive index, achieving a maximum sensitivity of 1199.18 nm∕refractive index unit for the range of refractive indices from 1.321 to 1.382. Using layer-by-layer self-assembly for deposition, both on the cladding and on the tip of the multimode segment, allows the reflected power to increase, which avoids the application of a mirror on the tip of the multimode segment. ; This work was supported in part by the Spanish Ministry of Education and Science-FEDER TEC2010-17805 and Government of Navarra research grants.
In this work, two all-fiber loop mirrors using a clover microstructured fiber for the simultaneous measurement of temperature and strain are presented. The sensing heads are formed by a short piece of clover microstructured fiber with 35 mm and 89 mm length respectively. The geometry of the fiber allowed observing different interferences created by the microstructured fiber core section. Different sensitivities to temperature and strain were obtained and, using a matrix method, it is possible to discriminate both physical parameters. Resolutions of ±2ºC and ±11 μ for the first structure and ±2.3ºC and ±18 μ for the second one, for temperature and strain, respectively, were attained. ; This work was supported in part by the European COST action TD1001, FEDER founds and the Spanish Government project TEC2013-47264-C2-2-R1.
Polarization management is of paramount importance in integrated optics, particularly for highly birefringent photonic platforms such as silicon-on-insulator. In this paper, we present a polarization beam splitter based on amultimode interference coupler incorporating tilted subwavelength gratings. The tilt provides accurate control of the structural anisotropy and enables independent selection of the beat length for two orthogonal polarization states. As a result, device length is reduced to less than 100 μm while simultaneously achieving broadband operation through subwavelength grating dispersion engineering. Insertion losses below 1 dB and an extinction ratio higher than 20 dB are demonstrated through three-dimensional FDTD simulation in a 131-nm bandwidth. ; This work was supported in part by the Spanish Ministry of Science, Innovation and Universities under Grants TEC2016-80718-R, TEC2015- 71127-C2-1-R (FPU scholarship 16/06762), and IJCI-2016-30484; in part by the Community of Madrid under Grant S2018/NMT-4326, and in part by the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie under Grant 734331. ; Peer reviewed
11 pags., 9 figs. ; Current bandwidth capacity provided by wavelength-division multiplexing and polarization-division multiplexing is insufficient to keep up with the increasing bandwidth demand required for new services. Mode-division multiplexing technology paves the way to further increase transmission and bandwidth capacities in photonic interconnects. In this work, we propose an ultra-broadband two-mode converter and de/multiplexer based on a sub-wavelength engineered multimode interference coupler, a 90° phase shifter, and a symmetric Y-junction for the silicon-on-insulator platform. Sub-wavelength grating waveguides enable dispersion engineering to further increase the bandwidth operation of conventional multimode interference coupler and, subsequently, of mode de/multiplexer based on them. Full three-dimensional simulations of the designed mode converter and de/multiplexer show insertion loss below than 0.84 dB and crosstalk lower than -20 dB over an unprecedented bandwidth of 300 nm (1.4-1.7 μm). The overall footprint of the proposed device is only 36 μ m × 3.7 μm. ; This work was supported in part by the Spanish Ministry of Economy and Competitiveness under Grant TEC2015-71127-C2-1-R (FPI scholarship BES-2016-077798), Grant TEC2016-80718-R, and Grant IJCI-2016-30484, in part by the Community of Madrid under Grant S2013/MIT-2790, in part by the EMPIR program (JRP-i22 14IND13 Photind), co-financed by the participating countries and the European Union's Horizon 2020 research and innovation program, and in part by the Horizon 2020 research and innovation program under the Marie Sklodowska-Curie Grant 734331 ; Peer Reviewed
In this paper, a novel approach for hybrid systems combining Raman distributed sensors with fiber Bragg grating (FBG) sensors to carry out distributed and quasi-distributed temperature/strain measurements was proposed and experimentally demonstrated. Three FBGs were inscribed by the point-by-point technique in a simple setup for type I femtosecond inscription in a pure silica core multimode gold-coated fiber. Employing a single fiber, temperatures up to 600 °C and strains up to 4144 µE approximately were measured simultaneously and without interferences between both distributed and point measurements. Moreover, a new calibration technique was implemented to calibrate the distributed temperature system using the FBG measurements as reference. ; Spanish Government FEDER Funds (TEC2016-76021-C2-2-R).
Proceeding and poster presented at: European Conference on Integrated Optics (ECIO). Eindhoven (Netherlands). 3-5 April, 2017 ; In this paper we report a multimode interference reflector (MIR)-based linear cavity mode-locked laser (MLL) operating in the telecom C-band with a repetition rate of 30 GHz as shown in Fig. 1. A pair of intra-cavity electro-optic phase modulators (EOPM) enables spectral tuning of the optical and the photo-detected RF spectrum. As an asymmetric bias voltage increases up to 6 V, the RF frequency shift reaches 3 MHz. This photonic integrated circuit (PIC) was rapidly prototyped using generic photonic integration technology platform via industrial Multi-Project Wafer (MPW) run ; This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 642355 FiWiN5G
The multimode interference (MMI) effect in a single mode-multimode-single mode (SMS) can be used fordevelopment of wavelength shift detection based sensors. In this work, the focus is centered on obtainingwavelength shifts with low cutoff single mode fibers, which allows exploring the wavelength range from600 to 1000 nm, where optical sources and detectors are less expensive than at longer wavelengths. Inaddition, the application of a reduction in the fiber diameter of the SMS structure by means of HF etching,combined with the deposition of a thin-film, enables to enhance the sensitivity of the devices at thesame time the objective mentioned before is achieved. In this sense, the effect of the deposition of a pHsensitive thin-film on SMS structures with different diameters allowed attaining a maximum sensitivityof 15 nm per pH unit in the range from pH 4 to pH 6, which improves by a factor of 3 the sensitivity ofSMS sensors without etching operating at longer wavelengths. ; This work was supported by the Spanish Agencia Estatal de Investigación (AEI) and Fondo Europeo de Desarrollo Regional (FEDER) (TEC2016-79367-C2-2-R, TEC2016-78047-R), Government of Navarra PI044 NANOSEN, Government of Navarra PC023-024 BIPOTSENS research grants and the Direction of Internationalization and Academic Collaboration of the Autonomous University of Tamaulipas.
Infectious disease outbreaks such as Ebola and other Viral Hemorrhagic Fevers (VHF) require low-complexity, specific, and differentiated diagnostics as illustrated by the recent outbreak in the Democratic Republic of Congo. Here, we describe amplification-free spectrally multiplex detection of four different VHF total RNA samples using multi-spot excitation on a multimode interference waveguide platform along with combinatorial fluorescence labeling of target nucleic acids. In these experiments, we observed an average of 8-fold greater fluorescence signal amplitudes for the Ebola total RNA sample compared to three other total RNA samples: Lake Victoria Marburg Virus, Ravn Marburg Virus, and Crimean-Congo Hemorrhagic Fever. We have attributed this amplitude amplification to an increased amount of RNA during synthesis of soluble glycoprotein in infection. This hypothesis is confirmed by single molecule detection of the total RNA sample after heat-activated release from the carrier microbeads. From these experiments, we observed at least a 5.3x higher RNA mass loading on the Ebola carrier microbeads compared to the Lake Victoria Marburg carrier microbeads, which is consistent with the known production of soluble glycoprotein during infection.
1221 1224 42 7 ; S ; This paper was published in Optics Letters and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OL.42.001221. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law The use of an integrated asymmetrical directional coupler for two-mode transmission at 1550 nm is analyzed. The design is based on silicon-on-insulator (SOI) technology and permits mode conversion and mode multiplexing/demultiplexing. In the nominal design, mode conversion and mode (de) multiplexing are achieved with 97% efficiency and a 23.4 dB crosstalk level in the 1540-1560 nm band using a 0.1 mu m gap. The dimension tolerance of the SOI process has been taken into account in the selection of the optimum design, and the coupling efficiency would remain above 82.3% (corresponding to 0.8 dB excess loss) with 3 sigma accuracy. A 90% efficiency has been experimentally obtained. García-Rodríguez, D.; Corral, JL.; Griol Barres, A.; Llorente Sáez, R. (2017). Dimensional variation tolerant mode converter/multiplexer fabricated in SOI technology for two-mode transmission at 1550 nm. Optics Letters. 42(7):1221-1224. doi:10.1364/OL.42.001221 Greenberg, M., & Orenstein, M. (2005). Multimode add-drop multiplexing by adiabatic linearly tapered coupling. Optics Express, 13(23), 9381. doi:10.1364/opex.13.009381 Uematsu, T., Ishizaka, Y., Kawaguchi, Y., Saitoh, K., & Koshiba, M. (2012). Design of a Compact Two-Mode Multi/Demultiplexer Consisting of Multimode Interference Waveguides and a Wavelength-Insensitive Phase Shifter for Mode-Division Multiplexing Transmission. Journal of Lightwave Technology, 30(15), 2421-2426. doi:10.1109/jlt.2012.2199961 Ding, Y., Xu, J., Da Ros, F., Huang, B., Ou, H., & Peucheret, C. (2013). On-chip two-mode division multiplexing using tapered directional coupler-based mode multiplexer and ...
Trabajo presentado en la Eurosensors 2017 Conference. París, 3–6 de septiembre de 2017. ; An optical fibre refractometer has been developed by etching and deposition of a thin film of indium tin oxide (ITO) on a single-mode-multimode-single-mode (SMS) fibre structure. The interference between modes in this structure is sensitive to the refractive index changes of the surrounding medium, achieving sensitivities of up to 7000 nm/RIU in the 1.333–1.338 RIU range. A salinity sensor has been implemented as a practical application of this proposed structure. Fast Fourier transform (FFT) analysis and tracking of an interference dip were used to monitor the interference between modes obtaining sensitivities of 0.99 nm/PSU and 0.025 rad/PSU, respectively. ; This work was supported in part by the Agencia Estatal de Investigación (AEI) and Fondo Europeo de Desarrollo Regional (FEDER) (TEC2016-78047-R) and by the Government of Navarre through its projects with references: 2016/PI008, 2016/PC025 and 2016/PC026. As well, it was partially supported by the Colombian Administrative Department of Science, Technology and Innovation - Colciencias, through the Program for national doctorates, calling 617 of 2013.
Optical fiber single mode-multimode-single mode (SMS) structures can be used as wavelength detection-based sensors. In this work, we focus on the performance at short wavelengths, where optical sources and detectors are less expensive. Here, a self-image band with a high transmission power is monitored in this short-wavelength range. In addition, the diameter and the length of the SMS structure have been optimized in order to improve the sensitivity of the device. In this sense, a maximum refractive index sensitivity of 305 nm/RIU was achieved by an etched SMS with a diameter of 34μ m. Furthermore, the obtained devices were used for testing the quality of automotive coolant and antifreeze liquid. ; This work was supported in part by the Programa de Fortalecimiento de la Calidad Educativa (PFCE) and the Programa para el Desarrollo Profesional Docente (PRODEP), in part by the Direction of Strategic Programs and Projects of the Autonomus University of Tamaulipas (UAT) and the direction of the Academic Multidisciplinary Reynosa-Rodhe Unit, in part by the Spanish Agencia Estatal de Investigación (AEI) and Fondo Europeo de Desarrollo Regional (FEDER) under Grant TEC2016-78047-R, in part by the Government of Navarra under Grant PC095-096 OPTISENS and Grant PC081-082 BIOPTSENS AVANZA, and in part by the Public University of Navarra under Grant PJUPNA26.
Potential niches for a power-over-fiber (PoF) technique can be found in hazardous areas that require controlling unauthorized access to risk areas and integration of multiple sensors, in scenarios avoiding electromagnetic interference, and the presence of ignition factors. This paper develops a PoF system that provides galvanic isolation between two ends of a fiber for remotely powering a proximity sensor as a proof of concept of the proposed technology. We analyze scalability issues for remotely powering multiple sensors in a specific application for the hazardous environment. The maximum number of remote sensors that can be optically powered and the limiting factors are also studied; considering different types of multimode optical fibers, span lengths, and wavelengths. We finally address the fiber mode field diameter effect as a factor that limits the maximum power to be injected into the fiber. This analysis shows the advantages of using step-index versus graded-index fibers. ; This work was supported in part by the Spanish Ministerio de Economía, Industria y Competitividad, Comunidad de Madrid and H2020 European Union Programme under Grants TEC2015-63826-C3-2-R and S2013/MIT-2790, in part by FSE, and in part by 5G PPP BlueSpace Project under Grant 762055. ; Publicado
Smart IoT solutions integrated into power grid stations are important due to their high economic and social value. Power over fiber technology to remotely feeding sensors and control electronics is a good choice in these environments of high electromagnetic interference. A sensing system design for magnetic field monitoring, fire and temperature/presence detection, and remotely fed by optical means is discussed. This design includes two types of nodes, smart and passive. Smart remote nodes have an energy manager to provide power on demand. Asymmetric splitting is proposed to optimize power distribution. Some tests on remote node power consumption, feeding, sensing, and centralized monitoring in one type of those nodes are successfully performed and reported. ; This work was supported in part by the Spanish Ministerio de Ciencia, Innovación y Universidades, Comunidad de Madrid and H2020 European Union Programme under Grants TEC2015-63826-C3-2-R and RTI2018-094669-B-C32, and Grant Y2018/EMT-4892 (TEFLON-CM), in part by FSE, and in part by 5G PPP Bluespace project under Grant nº 762055, respectively. ; Publicado
We explore phase transitions of polariton wave packets, first, to a soliton and then to a standing wave polariton condensate in a multimode microwire system, mediated by nonlinear polariton interactions. At low excitation density, we observe ballistic propagation of the multimode polariton wave packets arising from the interference between different transverse modes. With increasing excitation density, the wave packets transform into single-mode bright solitons due to effects of both intermodal and intramodal polariton-polariton scattering. Further increase of the excitation density increases thermalization speed, leading to relaxation of the polariton density from a solitonic spectrum distribution in momentum space down to low momenta, with the resultant formation of a nonequilibrium condensate manifested by a standing wave pattern across the whole sample. ; M. S. and D. N. K. acknowledge support from the Leverhulme Trust Grant No. RPG-2013-339. M. S., J. K. C., P. M. W., B. R., M. S. S., and D. N. K. acknowledge the support from the EPSRC Grants No. EP/J007544/1 and No. EP/N031776/1 and the ERC Advanced Grant EXCIPOL 320570. D. V. S. acknowledges the Russian Foundation for Basic Research (16-52-150006) and the ITMO University Fellowship through the Government of Russia Grant No. 074-U01. H. S. and I. A. S. acknowledge the support by the Research Fund of the University of Iceland, The Icelandic Research Fund, Grant No. 163082-051 and the Project 3.2614.2017/4.6 of the Ministry of Education and Science of Russian Federation. I. A. S., M. S. S., and D. N. K. Megagrant No. 14.Y26.31.0015 of the Ministry of Education and Science of Russian Federation. We thank Marzena Szymańska for helpful discussions. ; Peer Reviewed
The increment of bandwidth required for new services offered to users make necessary the use of optical fibres in data transmission. Glass optical fibres are widely used in long distance communications, and there are many devices implemented for using in these networks, but these technologies are sometimes expensive for their used in local loops. Different systems implemented over the established technology are used for increasing local loops bandwidth, but more services are demanded at home. Those applications require more bandwidth than the offered by the usual twisted copper pair. Multimode fibres (both silica and polymer) with larger core diameters and numerical aperture, allows for large tolerance on axial misalignments, which results in cheaper connectors as well as associated equipment, but with a bandwidth penalty with regards to their singlemode counterparts, mainly due to the introduction of modal dispersion. On the other hand, polymer optical fibre (POF) offers several advantages over conventional multimode optical fibre over short distances (ranging from 100m to 1000m) such as the even potential lower cost associated with its easiness of installation, splicing and connecting. This is due to the fact that POF is more flexible and ductile, making it easier to handle. Consequently, POF termination can be realized faster and cheaper than in the case of multimode silica fibre. Therefore, the number of applications that use POF is quickly increasing. POF is being used in video transmission in medical equipment, or in multimedia applications for civil aviation and high range cars, in-home and access networks, wireless LAN backbone or office LAN, and in intrinsic optical sensor networks among others. Even greater channel capacity can be available using a specific type of POF, perfluorinated Graded-Index POF (PF GIPOF), having low attenuation and large bandwidth from 650nm to 1300nm. Link lengths for in-building/home scenarios are short (less than 1 km), and thus the loss per unit length is of less importance. Transmission of 10Gbps data over 100m and transmission of 1.25Gbps Ethernet over 1 km have been experimentally demonstrated with PF GIPOF. On the other hand, combiners and multiplexers are basic elements in POF networks using Wavelength Division Multiplexing (WDM) and there are not that many already developed. It is important to have low losses devices and reconfiguration can be an additional feature in those networks. On the other hand, reconfigurable optical networks in critical applications demand devices able to have different functionalities, including switching. This work has focused in the development of different optical switches for a wide range of optical networks. Different switching technologies are available. Liquid crystals are widely used as displays, but they are also employed in telecommunications. Other common technology used in data routing is integrated optics. In this case, light propagates by means of a waveguide and the modification of its parameters makes possible switching operation. Micro-Electromechanical Mechanisms, MEMs, based in small mobile mirrors that can change the direction of the incident light when required are an important optical switching technology. The objective of the present work is the proposal of several optical switches using different technologies depending on the final application. Some of these structures have been experimentally tested whereas others have been simulated. Most of the presented switches use liquid crystals, having different functionalities and broadband operation range, so allowing wavelength division multiplexing. To these respect it has been developed an optical multiplexer/combiner and an advanced multifunctional optical switch (AMOS), both implemented with Nematic Liquid Crystal technology. It has also been developed a multiplexer/combiner based on Polymer Dispersed Liquid Crystals. The third kind of switches proposed are micro ring-resonators combined with liquid crystals. Micro ring-resonators consist of a circular waveguide attached to one or two straight waveguides acting like input and output ports. Light that passes through the structure can be filtered according to the ring resonator characteristics: ring length, coupling ratio, losses… The use of liquid crystal makes possible the tuning of the ring resonator filtering properties. The last proposed switch is made of a passive splitter and a Mach-Zehnder Interferometer. This kind of devices makes use of integrated optics and interference for switching purposes. The variation of the optical properties influencing the two light beam interference can be done in different ways: thermally, electrically… Finally, an automated optical characterization bench has been implemented in order to make easy the measurements. It is composed by a three axis translation stage with three actuators, several linear translation stages that allows the user to modify the bench structure for adapting it to his experiment, and different machinery for mounting the optics. ; The present research work has been supported by the following Spanish projects: TIC2003-038783 (DISFOTON), TEC2006-13273-C03-03-MIC (FOTOCOMIN) and TEC2009-14718-C03-03-MCI (DEDOS) of the Spanish Interministerial Commission on Science and Technology (CICYT), FACTOTEM-CM: S-005/ESP/000417, and FACTOTEM-II-CM: S2009/ESP-1781 and FENIS-CCG06-UC3M/TIC-619 of Comunidad Autónoma de Madrid. Additional financial support has been obtained form European Thematic Network SAMPA: Synclinic and Anticlinic Mesophases for Photonic Applications (HPRNCT- 2002-00202), carried out during the V Framework Program of the European Union, COST Action 299 FIDES: Optical Fibres Dedicated to Society, and from the European Network of Excellence: ePhoton/ONe+ (FP6-IST-027497), both carried out during the VI Framework Program of the European Union, and BONE: Building the Future Optical Network in Europe (FP7-ICT-216863) carried out during the VII Framework Program of the European Union.
