Radio-frequency ring resonators for self-referencing fiber-optic intensity sensors

A theoretical and experimental study of radiofrequency ring resonators (RR) for referencing and improving the sensitivity of fiber-optic intensity sensors (FOS) is reported. The separation between lead and transducer losses in the FOS is solved by converting the light intensity fluctuations to be measured into RR losses that produce high amplitude variations in the proximity of the RR resonance frequencies. Two different self-referencing techniques are developed. Via the definition of the measurement parameter RM , sensor linearity and sensitivity are analyzed. A calibration using an optical attenuator is reported to validate the model.Publicad

Ring Resonators with Sagnac Loops for Photonic Processing in DWDM Backbone Networks

In this paper, optical configurations based on ring resonators (RR) with an internal Sagnac (SG) loop in the feedback path, are analyzed in terms of their amplitude response and dispersive properties for filtering and chromatic dispersion managing in digital transmission systems over amplified single- mode fiber (SMF) spans in DWDM backbone networks. Design issues for the architecture as regards quadratic dispersion and magnitude distortion are provided. The RR+SG compound filter provides frequency tunability of the amplitude and dispersion peaks by adjusting a coupling coefficient of an optical coupler, with no need for using integrated thermo-optic nor current- injection based phase shifters. The configuration can be employed as an additional structure for a general RR-based design and synthesis architecture, allowing bandwidth increase of dispersion compensators and flexibility. The performance of a compound filter consisting of a two RR in series stage and a RR+SG filter are reported as a more compact and effective solution for existing multi-channel SMF backbone links operating at high bit rates. Design guidelines of an integrated ring resonator based on polymer technology for showing feasibility of the proposal is reported.This work was partially supported by Spanish CICYT (TEC2006-13273-C03-03-MIC), European project NoE EPhoton/One+, CAM (FACTOTEM-CM:S-0505/ESP/000417), FENIS-CCG06-UC3MITIC-0619.Publicad

CWDM self-referencing sensor network based on ring resonators in reflective configuration

A new scalable self-referencing sensor network with low insertion losses implemented in Coarse Wavelength Division Multiplexing (CWDM) technology is reported. It allows obtaining remote self-referenced measurements with a full-duplex fibre downlead up to 35 km long, with no need for optical amplification. Fibre Bragg gratings (FBG) are used in order to achieve a reflective configuration, thus increasing the sensitivity of the optical transducers. Low-cost off-the-shelf devices in CWDM technology can be used to implement and scale the network. Ring resonator (RR) based incoherent interferometers at the measuring points are used as selfreferencing technique. A theoretical analysis of power budget of the topology is reported, with a comparison between the proposed network and a conventional star topology. Finally, the new configuration has been experimentally demonstrated.This work has been supported by CICYT:TIC2003-03783, UC3M:FAVICOBIS and CAM:FACTOTEM-CM (S-0505/ESP/000417).Publicad

Multi-sensor system using plastic optical fibers for intrinsically safe level measurements

A system for measuring liquid level in multiple tanks using optical fibe technology has been developed. Oil fiel service industry or any sector requiring liquid level measurements in flammabl atmospheres can be benefite from this intrinsically safe technology. The device used a single lens for the emitting and receiving fibe and it is based on amplitude variations as a function of the liquid distance and not in time of fligh or phase detection. Being the firs fiber-opti liquid level sensor with those characteristics for long ranges (>200 cm). A simple model to describe their behavior has been derived and tested on two prototypes. A Monte-Carlo method is used to fi the experimental data and obtain the model parameters. High accuracy between experimental data and fitte curve is obtained. The prototypes have a good linearity, better than 1.5% FS (full scale). Sensor heads are made of plastic optical fiber (POF) that are easy to handle, flexible and economical. They are excited by 650 nm lasers, housed in ST-connectors to obtain compact and rough prototypes. Optical multiplexing is used to increase the measuring safety area. Frequency division multiplexing is used to address each sensor head. A discussion about the influenc of tilts and aberrations is also included.Publicad

Applications of Ring Resonators and fiber delay lines for sensors and WDM Networks

En esta tesis doctoral, se presentan diversas aportaciones científicas en el ámbito de las aplicaciones de la fibra óptica y de las comunicaciones ópticas. En primer lugar, la tesis doctoral describe nuevas técnicas de medida remota y multiplexación en longitud de onda (WDM), a través de fibra óptica monomodo, para sensores ópticos. Las técnicas de medida están orientadas a sensores de intensidad óptica y se basan en configuraciones ópticas implementadas mediante redes de Bragg en fibra y líneas de retardo en fibra recirculantes (anillo resonante) y no recirculantes. En el documento se describen matemáticamente dichas técnicas y se presentan medidas experimentales que verifican los modelos teóricos. En segundo lugar, la tesis contiene diversas contribuciones novedosas al diseño y simulación por ordenador de filtros fotónicos compuestos basados en el anillo resonante con interferómetro Sagnac, para la compensación de la dispersión cromática en enlaces de transmisión digital con fibra óptica. Por último, el documento incluye un listado de todas las referencias empleadas, un listado de los acrónimos empleados, así como las publicaciones y patentes obtenidas por el autor hasta la fecha.Los proyectos de la Comisión Interministerial de Ciencia y Tecnología (CICYT): TIC2003-03783 (DISFOTON) y TEC2006-13273-C03-03-MIC (FOTOCOMIN). El programa de I+D+i de la Comunidad Autónoma de Madrid: FACTOTEM-CM (S-0505/ESP/000417). La Acción Integrada Hispano-Portuguesa del Plan Nacional de I+D+i 2004-2007: Self-referenced fibre optic intensity configurations for single and multi-sensors (HP2007-0093). El proyecto cofinanciado por la Universidad Carlos III de Madrid y la Comunidad Autónoma de Madrid: Fotónica en visualización, comunicaciones y sensores (CCG06-UC3M/TIC-0619). Las ayudas a la movilidad de investigadores en formación que me concedió la Universidad Carlos III de Madrid en 2006 y 2007. La Red Temática Europea SAMPA (HPRN-CT-2002-00202) del 5º Programa Marco de la Unión Europea. La Acción Europea FIDES (COST Action 299) del 6º Programa Marco de la Unión Europea. Y las Redes de Excelencia Europea ePhoton/ONe+ (FP6-IST-027497) y BONE (FP7-ICT-216863), del 6º y 7º Programa Marco de la Unión Europea, respectivamente

Self-Referencing Fiber-Optic Intensity Sensors Using Ring Resonators and Fiber Bragg Gratings

An improved ring resonator self-referencing technique in a new reflection configuration for remote fiber-optic intensity sensors is demonstrated using fiber Bragg gratings. Sensor sensitivity doubles and a single fiber lead is used. The sensor is interrogated at two subcarrier frequencies having a high rejection of interference from laser source intensity fluctuations and loss in the fiber lead. We experimentally demonstrate the efficiency of the new reflection configuration, the usefulness of the theoretical model proposed, and discuss design parameters for optimum insertion lossesThis work was supported in part by CICYT (TIC2003-03783 and TEC2006-13273-C03-03-MIC), in part by UC3M (FAVICOBIS), in part by CAM (FACTOTEM-CM:S-0505/ESP/000417), and in part by COST 299.Publicad

Fault location in full-duplex optical fibre links using synchronized decay time detection

La ponencia se presentó en: VIII Reunión Española de Optoelectrónica OPTOEL’13 , celebrado los días 10-12 de Julio de 2013, lugar de celebración Alcalá de Henares (España).En este trabajo, se muestran los resultados obtenidos durante la evaluación experimental de un método de localización de cortes en enlaces full-dúplex de fibra óptica, empleando un método alternativo a medidas con Reflectómetros Ópticos en el Dominio del Tiempo (OTDR). El método utilizado consiste en comparar los tiempos de caída en los dos extremos del enlace de manera sincronizada cuando se produce un corte de fibra. Se han evaluado dos tipos de tecnologías de fibra, multimodo y monomodo, analizando las prestaciones del método en cada caso y para varios tipos de rotura de cable, considerando y comparando la precisión de las medidas así como las máximas distancias soportadas.Este trabajo ha sido financiado por los proyectos CICyT TEC2012-37983-C03-02 y FP7-ICT-2011 DISCUS (318137).European Community's Seventh Framework ProgramPublicad

Monitoring techniques in broadband access networks

The proceeding at: 17th International Conference on Transparent Optical Networks, ICTON2015, took place at 2015, July 5-9, in Budapest, (Hungary).Broadband access networks needs specific monitoring techniques at the physical layer to provide the quality of service required by the users. Similarities between sensor and access networks will be analysed to get best practices in both scenarios to provide novel monitoring and self-reference techniques.This work has received funding from the Spanish Ministry of Economía y Competitividad under projects TEC2012-37983-C03-02 (CFOOT-TIC) and TEC2009-14718-C03-03, and support from the Comunidad de Madrid project under grant S2013/MIT-2790 (SINFOTON-CM).publicad

Self-referencing techniques in photonics sensors and multiplexing

11 pages, 8 figures.-- Contributed to: "Photonic Materials, Devices, and Applications II", ed. by Serpengüzel, Ali; Badenes, Gonçal; Righini, Giancarlo C. (Maspalomas, Spain, May 2, 2007).A short review of self-reference techniques for remote fiber-optic intensity sensors and possible integration in multiplexing sensor networks is reported. Special focus is given to developments on radio-frequency (RF) source modulation techniques in interferometric configurations operating under incoherent regime. Experimental results on ring resonator (RR) configurations in transmission and reflection modes are included. Sensitivity, optimum insertion losses and robustness to intensity error fluctuations are reported. Sensors are interrogated at two sub carrier frequencies having a high rejection of interference from laser source intensity fluctuations and loss in the fiber lead. Dependence on source coherence is also analysed.Scalable self-referencing sensor networks with low insertion losses implemented in Coarse Wavelength Division Multiplexing (CWDM) technology are reported. The possibility of remote self-referenced measurements using a full-duplex fiber down-lead tenths of kilometers long with no need for optical amplification is also described. Fiber Bragg gratings (FBG) are used in the reflection configuration, thus increasing the sensitivity of the optical transducers. Low-cost off-the-shelf devices in CWDM and DWDM technology can be used to implement and scale the network.Applications to specific photonic sensors are also envisaged and these techniques can be used in networks of microfiber loop resonators, being the microfiber loop the sensing element itself.This work was partially supported by CICYT (TEC2006-13273-C03-03-MIC), COST299, EPhoton/One+(NoE-ISTEU), FENIS-CCG06-UC3M/TIC-0619, CAM (FACTOTEM-CM:S-0505/ESP/000417).Publicad

Electrical FIR Filter With Optical Coefficients for Self-Referencing WDM Intensity Sensors

In this letter, a novel radio-frequency finite impulse reponse (FIR) electrooptical configuration for self-referencing optical wavelength-division-multiplexed intensity sensors is reported. By employing the proposed low-cost electronic FIR filter at the reception stage, the use of a 14-km fiber delay coil is avoided for a 2-kHz modulation frequency, preserving sensitivity and self-reference. The technique is analyzed following the Z-transform formalism and measurements validating the theoretical model are reported.Publicad