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

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

Multimode fibre broadband access and self-referencing sensor networks

Future Internet Access technologies are supposed to bring us a very performing connection to the main door of our homes. At the same time, new services and devices and their increase use will require data transfers at speeds exceeding 1Gbps inside the building or home at the horizon 2012. Both drivers lead to the deployment of a high-quality, futureproof network inside buildings and homes. This environment may end up taking advantage of optical cabling solutions as an alternative to more traditional copper or pure wireless approaches. Related to this latter fact, the objectives of this work are: • The achievement of a full convergence scenario between optical networks from the telecommunication services providers to the end users underscores the necessity of accurate and realistic fibre models in assessing the performance of broadband access networks with the premises of high-capacity and total compatibility. Silicabased MMFs and PF GIPOFs are the most promising candidates for such a convergence within the in-building/home scenario. Contributions to a better understanding of the possibilities of signal transmission outside the baseband of such fibres are investigated, in order to extend their capabilities, together with the evaluation of current fibre frequency response theoretical models by means of an extensive set of measurements. • The achievement of a full convergence scenario between optical networks from the telecommunication services providers to the end users is also contingent on research and development in the field of optical fibre sensors, mainly driven by the growing demand of fully building/home and industry automation, leading to a reliable integration of the optical networks. Related to this, development of multiplexing and measurement techniques for fibre-optic intensity-based sensors are analyzed and experimentally investigated. In the sensor network topology proposed, by replacing the fibre delay line with an electronic delay in the reception stage, it is possible to avoid long fibre delay coils in the remote sensing points and achieving a compact, flexible and re-configurable self-referencing technique. Applications in both scenarios can be considered, on the one hand the in-building/home network and on the other hand the WDM-PON access network topology through which operators provision the different services. -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------La demanda e incursión en la sociedad de nuevos servicios multimedia, tales como televisión por Internet (IPTV, Internet Protocol Television) o video-bajo-demanda (VoD, Video on Demand) junto con el incremento del tráfico de datos requerido para nuevas aplicaciones como la televisión por alta definición (HDTV, High-Definition Television) y transferencias P2P (Peer-to-Peer) exigen un aumento de la capacidad de las redes de datos desplegadas hoy en día. Para hacer frente a este aumento de la demanda de capacidad de las redes de acceso, los proveedores de estos servicios multimedia están reemplazando las infraestructuras de las redes de acceso basadas en cable coaxial, tales como xDSL (x- Digital Subscriber Line), por otras nuevas de mayor capacidad desplegadas en fibra óptica, permitiendo la interconexión de los nodos de red con los múltiples hogares y negocios de los abonados, constituyendo el núcleo de lo que es conocido como “fibra hasta el hogar/nodo/edificio” o redes FTTx. Tradicionalmente el despliegue de las redes ópticas se ha realizado mediante fibra óptica monomodo de sílice (SMF, Singlemode Fibre). Ello es debido a su gran ancho de banda que permite una gran capacidad de transporte de servicios y datos. Es por ello que en base a este tipo de fibra se ha realizado el despliegue de redes de distribución y metropolitanas y, de un tiempo a esta parte, incluso penetrando su instalación en las redes de acceso. Junto con lo anteriormente expuesto, existe una necesidad de convergencia de servicios e infraestructuras dentro de las redes de acceso. Actualmente, cables coaxiales, par trenzado de cobre e incluso señales inalámbricas se encuentran entremezcladas dentro del hogar proporcionando servicios diferentes con apenas cooperación entre ellos. Una infraestructura común dentro del hogar en el que una gran cantidad de servicios pudieran ser integrados y soportados por la misma sería un aspecto deseable. Y es más, frente a las desventajas de infraestructuras basadas en cable de cobre (cable coaxial y par trenzado) como son susceptibilidad a interferencias electromagnéticas, presencia de crosstalk y relativa baja capacidad de transporte de datos, las fibras ópticas (tanto en su versión monomodo como multimodo) presentan las ventajas de un menor volumen, mayor flexibilidad y menor peso junto con una capacidad mayor de transmisión de datos sobre distancias mayores. Es por esto que éstas últimas constituyen la base para las futuras redes de acceso en el hogar

Temperature impairment characterization in radio-over-multimode fiber systems

Arbitrary operating conditions, such as the temperature dependence in the fiber link impose a challenge for the extension of radio-over-multimode fiber techniques. Temperature impairment characterization is analyzed over the broadband transmission bands that can be present in the frequency response of multimode fiber (MMF) supporting multiple-GHz carriers delivering schemes. Experimental results show that these transmission bands are dramatically influenced by the hysteresis of heating and cooling temperature cycles, respectively. The influence of the MMF graded index exponent tolerance on frequency response at higher bands is also analyzed. And this variation can be directly attributed to environmental temperature changes that could affect the MMF link. Additionally, selective mode-launching schemes combined with the use of narrow line-width optical sources are experimentally demonstrated to enable broadband transmission, not only at short but also at middle-reach distances over MMFs.This work was supported by Spanish CICyT project TEC2009-14718-C03-03 from the Spanish Ministry of Science, and by project FACTOTEM-II-CM: S2009/ESP-1781 of Comunidad Autónoma de Madrid.Publicad

Temperature Impairment Characterization in Radio-Over-Multimode Fiber Systems

The proceeding at: SPIE Photonics West 2012.Broadband Access Communication Technologies VI., took place in 2012, January 21-26, in San Francisco, California (USA). The event Web site at: http://spie.org/conferences-and-exhibitions/past-events/past-conferences-and-exhibitions/past-events/photonics-west/photonics-west-2012An emerging theme in next-generation access research includes seamless wireline-wireless convergence addressed by Radio-over-Fiber (RoF) technologies. Optical cabling solutions offer th e possibility for semi-transparent transport through the access network microwave to mm-wave radio carriers commonly employed for creating high-capacity picocell wireless networks, attending present demands from the wireless technologies, with portable/mobile devices converging with photonics. Advanced RoF techniques can efficiently generate and transport such carriers, and deliver them to simplified antenna stations or radio access points (RAPs). Thus, they can convey high data rates in comprehensive modulation formats on multiple-GHz carriers in MMF networks. Selective mode-launching schemes combined with the use of narrow linewidth optical sources are experimentally demonstrated to enable broadband RF, microwave and mm-wave transmission in short- and middle-reach distances over silica-based multimode optical fibers (MMFs); and are rev iewed in this pap er. However, arbitrary operating conditions, such as the temperature dependence in the fiber link, impose a great challenge for the extension of the RoMMF technology. Temperature impairment ch aracterization is analyzed over the broadband transmission bands that are present, under certain operating link conditions, in the frequency response performance of MMF to support multiple GHz carrier delivering schemes, thus contributing to fault link prevention.Publicad

Polymer Optical Fiber Intensity-Based Sensor for Liquid-Level Measurements in Volumetric Flasks for Industrial Application

A low-cost intensity-based polymer optical fiber (POF) sensor for liquid detection applied to volumetric flasks is presented. Experimental results demonstrate the viability of the POF-based sensor system in a high-accuracy liquid level measurement scenario. Moreover, a wireless mesh sensor network based on ZigBee specification protocol to address multiplexed POF-based sensor is also developed. Experimental results demonstrate the feasibility to address a high number of optical sensors in an industrial process framework by means of this low-cost wireless solution.This work has been supported by Spanish CICyT project TEC2009-14718-C03-03 (DEDOS) and by FACTOTEM-2/ 2009/S2009/ESP-1781.Publicad

Interrogation of Remote Intensity-Based Fiber-Optic Sensors Deploying Delay Lines in the Virtual Domain

This proceeding at: 22nd International Conference on Optical Fibre Sensors (OFS-2012), took place in 2012 October, 14, in Chine.In this work a self-referencing intensity-based fiber-optic sensor using virtual instrumentation is presented. The use of virtual delay lines along with novel self-referencing techniques minimizing resolution and using a single frequency avoids all-optical or electrical-based delay lines approaches at reception. This solution preserves the self-referencing and performance characteristics of the proposed optical sensing topology, and leads to a more compact solution with higher flexibility for the multiple interrogation of remote sensing points. Results are presented for a displacement sensor demonstrating the concept feasibility.This work has been supported by Spanish CICyT project TEC2009-14718-C03-03 from the Spanish Ministry of Science,and by project FACTOTEM-II-C: S2009/ESP-1781 of Comunidad de Autónoma de Madrid.Publicad

Remote interrogation of WDM fiber-optic intensity sensors deploying delay lines in the virtual domain

In this work a radio-frequency self-referencing WDM intensity-based fiber-optic sensor operating in reflective configuration and using virtual instrumentation is presented. The use of virtual delay lines at the reception stage, along with novel flexible self-referencing techniques, and using a single frequency, avoids all-optical or electrical-based delay lines approaches. This solution preserves the self-referencing and performance characteristics of the proposed WDM-based optical sensing topology, and leads to a more compact solution with higher flexibility for the multiple interrogation of remote sensing points in a sensor network. Results are presented for a displacement sensor demonstrating the concept feasibility.This work has been supported by Spanish CICyT projects TEC2012-37983-C03-02 and TEC2009-14718-C03-03 from the Spanish Ministry of Science.Publicad

Intensity-Based Optical Systems for Fluid Level Detection

In this work different patented optical sensing solutions are reviewed, mostly for their application of measuring fluid level within tanks, containers or bio-mass boilers in condominiums, thus providing an intrinsically safe sensing scenario within harsh and hazardous environments, due to the passive nature of light. In general, the intensity modulation of the light is very attractive since it is simple in concept, reliable, and can produce optical sensors which offer a wide range of applications at lower costs, thus facilitating their final commercialization and market spread. The optical sensing solutions discussed in this work include a fiber-optic sensor for fluid detection/level with intrinsic self-referencing property thus solving one of the main drawbacks when using intensity-based sensors, namely the undesirable and unexpected optical power fluctuations when operating. Moreover, a low-cost intensity-based POF sensor for fuel level measurements in paramotoring and powered paragliding is presented. It features a very simple and a very low-cost solution for these sports, attending the increasing demand of new and more sophisticated embedded sensors in the flight instrumental. Going on from this, a fiber-optic fluid level sensor for a range greater than 2m is described. The system uses a single lens and a single fiber but being possible to increase the measuring safety area by optical multiplexing. Finally, a fluid level sensor based on a Light Dependent Resistor (LDR), which includes a temperature control scheme, is presented. Its final embodiment design is also shown and described.This work has been supported by Spanish CICyT project TEC2009-14718-C03-03 and by project FACTOTEM-IICM:S2009/ESP-1781 of Comunidad Autónoma de Madrid.Publicad

Self-referenced optical networks for remote interrogation of quasi-distributed fiber-optic intensity sensors

Different multiplexing techniques for passively addressingfiber-optic sensors and compensation schemes forovercoming the undesirable optical signal losses to provide self-referenced quasi-distributed sensing from in-tensity-basedfiber-optic point sensors are revisited. Furthermore, a passive wavelength division multiplexing(WDM) network operating in reflective configuration with remote Radio-Frequency self-referencedfiber-opticintensity sensors with electro-optical configuration is proposed. Delay lines in the electrical domain providemore compact sensor-heads and easy-reconfigurable performance of the sensing points. The technique is ana-lyzed following the Z-transform formalism and measurements validating the theoretical model are reported.There are two measurement parameters providing self-referenced remote interrogation for the sensing heads.The paper shows their experimental validation in a 2-sensor network based on tapered SMF micro-displacementsensors, testing sensor self-referencing as well as sensor crosstalk. Those results provide the background toextrapolate them to a quasi-distributed passive CWDM-based 16-sensor network at around 65 km of remotedistance from the central office, with possible upgrade to a 25 km-long DWDM-based 48-sensor network.The authors will like to thank Dr. Julio Montalvo, Dr. José Manuel Baptista, Dr. José Luis Santos and Dr. Alberto Tapetado for their fruitful technical discussions and their support during the experiments. Theauthors will also like to thank Dr. Orlando Frazao for his valuablesupport during the experiments. This work was supported in part by the Spanish Ministry of Science, Innovation and Universities, the Directorate for Research and Innovation at Madrid region and H2020 European Union programme, under Grant RTI2018-094669-B-C32, Grant P2018/NMT-4326, and inpart by FSE, respectively