Novel tuneable filter based on MZ and an amplified ring resonator for OFDM networks

IEEE Lasers and Electro-Optics Society. 1999 Annual Meeting. 8-11 November 1999. San Francisco, CAA novel reconfigurable fibre based tuneable filter is proposed. The module relies on a cascaded connection of Mach-Zehnders and an amplified fibre ring resonator. MHz range adjustable FHWM bandwidths and high crosstalk are achieved.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

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

Synthesis of optical filters using sagnac interferometer in ring resonator

We propose a new synthesis method for the implementation of infinite impulse response filters, using a Sagnac interferometer within a ring resonator. This structure permits the synthesis of second-order optical functions per stage. We present the parameters of the structure, which are related to the poles position, radial and azimuthal, and the design procedure, with an example of an autorregresive filter.Publicad

Filtros ópticos de segundo orden con un solo resonador en anillo

4 págs, 8 figs.-- Presentado en: 3ª Reunión Española de Optoelectrónica (OPTOEL'03), Leganés (Madrid), 14-16 julio 2003.En los últimos años los Resonadores en Anillo (RA) se han investigado intensamente por su uso en el dominio óptico en aplicaciones que van desde, filtros de frecuencia óptica para sistemas de multiplexación por longitud de onda (WDM, del inglés Wavelength División Multiplexing), dispositivos Add/Drop, convertidores FSK a ASK, mux/demux, conmutación óptica, sensado óptico, filtros interleaver, láseres, etc. Estos dispositivos pueden constituir sistemas de orden mayor si se acoplan directamente, o se concatenan en serie.En este artículo se presenta una forma de conseguir sistemas de segundo orden sin la necesidad de dos anillo en cascada o acoplados directamente. Y se hace una comparación entre dos estructuras de segundo orden realizadas con diferentes dispositivos.Este trabajo ha sido financiado por la Comunidad de Madrid (CAM-07T-0011-2001).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

Optical reconfigurable demultiplexer based on Bragg grating assisted ring resonators

A polarization independent reconfigurable optical demultiplexer with low crosstalk between adjacent channels and high number of potential allocated channels is designed on silicon on insulator technology. On to off state transitions can be implemented by changing the coupling factor or the ring length. Wavelength selective switch units are cascaded to form the demultiplexer. Crosstalks below -30dB with 50GHz channel spacing and losses below 1.5dB in the off state are obtained from simulations. Designs using carrier dispersion effect and power consumption estimations are included.This work has been sponsored by the Spanish Economy and Education Ministries through grants (Ref.TEC2012-37983-C03-02).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

Power, sensitivity, and response time optimization in TDM self-reference intensity sensor networks with ring resonators

In this paper, we report on design rules for optimizing the response of intensity sensors embedded in ring resonators (RR) as part of a frequency based self-referencing method. Time division multiplexing sensor networks require a time response analysis for properly addressing the self-reference sensors. The selected measurement and reference frequencies are multiples of the RR Free Spectral Range to improve signal to noise ratio and avoid RR coupling coefficient (K) tolerance influence on the measurements. A weighting function that models the trade-off between high sensitivity and fast response for defining the operation point in terms of K and ring losses is also givenSpanish Ministry of Economy and Competitiveness (TEC2015-63826-C3-2-R); Comunidad de Madrid (S2013/MIT-2790)

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