showing 17 related works from this author
A magnetostrictive sensor interrogated by fiber gratings for DC-current and temperature discrimination
2000
A magnetostrictive sensor head with temperature compensation has been developed for measurement of static magnetic fields. The device consists on two different alloys with similar thermal expansion coefficient one of which has a giant magnetostriction, the expansion of both materials produced by heat and magnetism is detected by two fiber gratings. One of the gratings measures the temperature of the sensor and the difference between the wavelengths reflected by the gratings is a measurement of the magnetically induced strain.
Photonic microwave tunable single-bandpass filter based on a Mach-Zehnder interferometer
2006
The authors present the theoretical analysis and experimental demonstration of a novel single-bandpass tunable microwave filter. The filter is based on a broadband optical source and a fiber Mach-Zehnder interferometer and shows a high Q factor over a tuning range of 5-17 GHz. A generalized analysis considering that the optical signal propagates along optical delay lines with a dispersion slope different from zero is presented.
Electronic tuning of delay lines based on chirped fiber gratings for phased arrays powered by a single optical carrier
2004
We propose a variable delay line for phased arrays antennas based on a chirped fiber grating. The line operates with an optical carrier at constant wavelength and the time delay of the radiofrequency modulating signal is modified stretching the grating with a piezoelectric translator, the grating response can be tuned at a speed of 0.68 nm/ms.
Simple high-resolution wavelength monitor based on a fiber Bragg grating
2004
A compact and low-cost device for monitoring the peak wavelength of single-peak spectral distributions is presented. The system is based on the transmission properties of a fiber Bragg grating when its period is modulated. Different types of optical signal, such as the emission of distributed-feedback lasers and the reflection of a broadband optical source produced by fiber gratings used in sensor systems, can be measured with this device. We demonstrate that a high wavelength resolution of micro 1 pm can be achieved and that our proposal can be used for real-time monitoring.
High-efficiency Q-switched erbium fiber laser using a Bragg grating-based modulator
2002
Abstract In this work we analyze the behavior of an erbium-doped fiber laser which is based on a simple scheme. Excitation of the active medium is performed in the 980 nm pump band with a CW semiconductor laser source. Two fiber Bragg gratings acting as mirrors of the Fabry–Perot laser cavity were used. One of these gratings was mounted over a piezoelectric (PZT) element. By applying voltage pulses to the piezoelectric, the laser cavity was temporally modulated and Q-switched laser pulses up to 530 mW peak powers at 3 kHz were obtained. Typical laser emission of 2–3 μs temporal widths and 0.1 nm of optical bandwidth have been achieved when the system was operated at 18.5 kHz repetition rate…
Tunable and reconfigurable microwave filter by use of a Bragg-grating-based acousto-optic superlattice modulator
2005
We present an all-optical novel configuration for implementing multitap transversal filters by use of a broadband source sliced by fiber Bragg grating arrays generated by propagating an acoustic wave along a strong uniform fiber Bragg grating. The tunability and reconfigurability of the microwave filter are demonstrated.
Tunable chirp in Bragg gratings written in tapered core fibers
2002
In this paper we present a technique to control the chirp of a fiber grating capable to produce positive or negative chirp in a single grating. The device is based on a uniform period grating written in a tapered core fiber, this grating has a positive chirp that can be reduced and removed by subjecting the fiber to mechanical stress, after some stress level the grating chirps to negative values. A chirp range of ±4 nm with respect to a central wavelength of 1546 nm has been experimentally achieved.
White light sources filtered with fiber Bragg gratings for RF-photonics applications
2003
Abstract In this paper we demonstrate that broadband light emitters filtered with fiber Bragg gratings are a suitable light source for RF-photonics applications. A 0.075 nm bandwidth fiber grating illuminated by a light emitter of 40 nm bandwidth has been used as light source to feed a microwave phase shifter based on a chirped fiber Bragg grating. The device operates successfully in the tested frequency range (0.5–6) GHz and has been optically tuned in a range of 4 nm.
Photonic processing of microwave signals
2005
In this paper, recent advances in the implementation of photonic tuneable transversal filters for RF signal processing developed by the Optical Communications Group are described. After a brief introduction to the field and the basic concepts, limiting factors and application of these filters are described in the field. This is based on a distinction between filters based on wavelength tuneable optical taps and others based on the tuneability of the dispersive elements that provide the time delay between samples. Recently developed approaches have also been discussed.
Advanced Optical Processing of Microwave Signals
2005
The authors present a review on the recent approaches proposed to implement transversal RF filters. Different tunable transversal filters consisting of wavelength tunable optical taps and those employing the tunability of dispersive devices are presented showing their high-performance characteristics. A comprehensive review of the fundamentals and a discussion on the main limitation of these structures are also included.
Tunable Dispersion Compensator Based on a Fiber Bragg Grating Written in a Tapered Fiber
2004
We report a novel dispersion tunable device for first-order dispersion compensation. It is based on a fiber Bragg grating written in a tapered fiber with a specific profile. The taper profile allows tuning the dispersion of the grating by stretching the fiber while the linearity of the group delay is preserved. A device with 0.8 nm of useful bandwidth and dispersion value tunable over more than 400 ps/nm is reported.
Fabrication of Optical Fiber Devices
2004
In this paper we present the main research activities of the Laboratorio de Fibras Opticas del Instituto de Ciencia de los Materiales de la Universidad de Valencia. We show some of the main results obtained for devices based on tapered fibers, fiber Bragg gratings, acousto-optic effects and photonic crystal fibers.
Tunable all-optical negative multitap microwave filters based on uniform fiber Bragg gratings.
2003
We present a novel and simple technique for obtaining transversal filters with negative coefficients by using uniform fiber Bragg gratings. We demonstrate a wide tuning range, good performance, low cost, and easy implementation of multitap filters in an all-optical passive configuration in which negative taps are obtained by use of the transmission of a broadband source through uniform Bragg gratings.
Tunable chirped fibre Bragg grating device controlled by variable magnetic fields
2002
A novel dynamic chirping fibre Bragg grating device based on a magnetic field applied to a magnetostrictive transducer capable of tuning its dispersion is presented. Chirping ranges up to 300 ps/nm have been demonstrated, which are suitable for several applications such as tunable transversal filtering and dynamic dispersion compensation.
Automatic tunable and reconfigurable fiberoptic microwave filters based on a broadband optical source sliced by uniform fiber Bragg gratings.
2002
We demonstrate an automatic tunable transversal notch filter based on uniform fiber Bragg gratings and a broadband optical source. High tunability can be performed by stretching the fiber with the gratings written in series. Also, high sidelobe supression can be achieved by introducing tunable attenuators in a parallel configuration of the gratings.
Simultaneous temperature and ac-current measurements for high voltage lines using fiber Bragg gratings
2006
We present an optical ac-current sensor, based on a fiber Bragg grating stretched by a magnetostrictive material, which enables a simultaneous measurement of high ac-currents and temperature. The proposed system is appropriated to monitor high voltages lines and can be installed without interrupting the current line, being characterized by an inherent electrical isolation.
<title>Tunable chirp in Bragg gratings written in tapered core fibers</title>
2001
In this paper we present a technique to control the chirp of a fiber grating capable to produce positive or negative chirp in a single grating. The device is based ona uniform period grating written in a tapered core fiber, this grating has a positive chirp that can be reduced and removed by subjecting the fiber to mechanical stress, after some stress level the grating chirps to negative values. A chirp range of +/- 4 nm with respect to a central wavelength of 1546 nm has been experimentally achieved.