Sagnac loop in ring resonators for tunable optical filters

General filter architecture using co- and counterpropagation signals are studied. A specific configuration based on a Sagnac loop within a ring resonator is analyzed. Novel tuning, apart from conventional tuning, is achieved by changing the coupling ratio of a coupler through the adjustment of the equivalent loop length. Full equations describing the filter behavior in passive and active configurations, and simple closed-form formulas to compute the tuning, tolerance, and full-width at half-maximum are reported. The performance of these devices is discussed for their application as selective or channel-dropping ultra-narrow-band filters. The effect of losses and their dispersion properties are also discussed. These devices can be conveniently implemented, using silicon- or InP-integrated optic technology, for they have high free spectral ranges.Publicad

Tunable Optical Filters Using Compound Ring Resonators for DWDM

The device is based on a loop mirror in a ring resonator. The loop mirror allows tuning by changing the coupling coefficient of a directional coupler. The loop mirror is implemented using a Sagnac configuration to have the same optical path between the signals to be interfered (copropagating and counterpropagating ones). The filter structure allows optical integration for having higher free-spectral ranges. Simple design equations for the filter parameters and the tuning are reported. Measurements on a passive optical fiber tunable filter are presented. There is a good agreement between measurements and theory.Publicad

Measurements On Passive Tunable Optical Filters For DWDM

WFOPC 2002 IEEE/LEOS Workshop on Fibre and Optical Passive Components, University of Glasgow, Scotland, on 5th-6th June 2002.Measurements on a passive optical fibre tunable filter are presented. The device is based on a loop mirror in a ring resonator. The loop mirror allows tuning by changing the coupling coefficient of a coupler. The novel filter structure allows planar optical integration for having higher free spectral ranges. Novel and simple design equations for the filter parameters and the tuning process are reported. There is a good agreement between measurements and theory.Universidad Carlos III de MadridPublicad

Datos acerca de la vegetación briofítica terrícola en Salamanca

Se estudian diversas comunidades briofíticas terrícolas presentes en la provincia de Salamanca, comentándose diversos aspectos sinecológicos, sinfisionómicos, sintaxonómicos y sincorológicos de las mismas.This is a study of the terricolous bryophytic vegetation in the Salamanca province, with some comments on synecologic, symphysionomic, syntaxonomic and synchorologic aspects

Binary Search Algorithm for Mixed Integer Optimization: Application to energy management in a microgrid

This paper presents a binary search algorithm to deal with binary variables in mixed integer optimization problems. One example of this kind of problem is the optimal operation of hydrogen storage and energy sale and purchase into a microgrids context. In this work was studied a system composed by a microgrid that has a connection with the external electrical network and a charging station for electric cars. The system modeling was carried out by the Energy Hubs methodology. The proposed algorithm transforms the MIQP (Mixed Integer Quadratic Program) problem into a QP (Quadratic Program) that is easier to solve. In this way the overall control task is carried out the electricity purchase and sale to the power grid, maximizes the use of renewable energy sources, manages the use of energy storages and supplies the charge of the parked vehicles.Ministerio de Economía y Competitividad DPI2013-46912-C2-1-RUniversidad de Sevilla CNPq401126/2014-5Universidad de Sevilla CNPq303702/2011-

Tropical Medicine: Sleeping Sickness

[ES]Raquel Cade (Angie Dickinson), una misionera, viaja al Congo Belga en 1939 para ayudar como enfermera al Dr. Bikel (Douglas Spencer) en el Hospital de la Misión de Dibela. Nada más llegar, el médico fallece de un ataque cardiaco y Raquel tiene que enfrentarse con las costumbres y creencias religiosas de los nativos. El coronel Henry Derode (Peter Finch), el jefe del destacamento del Ejército belga, le ofrece ayudarla a abandonar el lugar pero no acepta. Las cosas van mal, pero todo cambia cuando se ve obligada a intervenir a un niño de una apendicitis aguda, a partir de ese momento la tribu estará dividida. Su situación mejora al estrellarse un avión en las proximidades y atender al único superviviente, un médico llamado Paul Wilton (Roger Moore).[EN]Raquel Cade (Angie Dickinson) is a missionary nurse who, in 1939, travels to Belgian Congo in order to help Dr. Bikel (Douglas Spencer) in Dibella’s Mission Hospital. Just after her arrival the doctor dies because of a heart attack, and Rachel has to confront the native’s habits and religious beliefs. Colonel Henry Derode (Peter Finch), the detachment commander of the Belgian army, offers her his help to abandon the place, but she does not accept it. Things seem to go wrong, but everything changes when she has to perform an appendicitis surgery on a child. As of that moment, the tribe is divided. Her situation improves when an airplane crashes near there and she assists the only survivor, a doctor called Paul Wilton (Roger Moore)

Optical router for optical fiber sensor networks based on a liquid crystal cell

Optical fiber sensor networks are evolving rapidly. They are used because of the inert nature of optical fibers allowing no electromagnetic interference and safe applications in inflammable atmospheres; other relevant characteristics are their low weights and wide bandwidths as a transmission medium. In any case, it is very interesting to have specific components such as optical routers for selecting a certain path in a network with no optical to electrical and electrical to optical conversions. In this paper, we propose an all-optical router based on liquid crystals, polarizers, and a spatial split polarization beam splitter. The implemented device is designed to operate with visible light and it has been tested with plastic optical fibers. It has a crosstalk of 14 dB between selected ON channels and nonoperative OFF channels and 11-dB insertion losses. An average switch time of 100 ms is measured. The device checks the optical power level in each channel and, in case of failure, automatically switches to an operative channel while an alarm is activated.Publicad

Bryoflora of tbe City of Salamanca (Spain)

Aytjso, i. E.; ELÍAS RivAs, M. i. & RIJP¡OFRA GIRALDo, i. L. 1995. Brioflora de la Ciudad de Salamanca. Bol. Coniplatensis 20: 45-53. Se citan 38 briófitos (37 musgos y 1 hepática) para la ciudad de Salamanca, 6 de los cuales son novedad para la provincia.Ayuso. J. B.~ ELÍAS RIvAS, M. J. & RUPIOBRA GIRALDo, 1. L. ¡995. Brioflora de la Ciudad de Salamanca. Boí. Complatensts 20: 45-53. Thirty eight bryophytes (37 mosses and ¡ liverwort) are reponed from the city of Salamanca (Spain). 6 are newly for the province