S. Sales

Solutions to the synthesis problem of optical delay line filters.

We report new design methods for the synthesis of incoherent low-pass fiber-optic delay line filters with finite impulse responses. These structures are considerably simpler in their operation than infinite impulse response filters, are always stable, and are capable of performing almost the same signal-processing operations. Some of their implementations and applications as adaptive filters or for demultiplexing of high-definition television signals are presented and discussed.

Tunable dispersion device based on a tapered fiber Bragg grating and nonuniform magnetic fields

We present a new variable dispersion device based on tuning the chirp of a tapered fiber Bragg grating by means of a magnetic transducer. By using a nonuniform magnetic field, we demonstrate a 188-472-ps/nm dispersion tuning range, suitable for tunable radio-frequency filters and dispersion compensation, among others.

Continuous tuning of photonic transversal filter based on the modification of tapped weights

We propose and experimentally demonstrate a novel technique to tune the microwave photonic filter which is based on the sinusoidal modulation superimposed to the envelope of the filter coefficients. This configuration overcomes the use of tunable optical sources and optical dispersive devices. To the best of our knowledge, these are the first experimental results where the resonances of the cited filters are shifted by changing the weight of the optical taps

Wavelength conversion of SCM signals using semiconductor optical amplifiers: theory, experiments, and applications

In this paper, we deal with the subject of cross-gain modulation (XGM) and cross-phase modulation (XPM) semiconductor optical amplifier-based wavelength conversion of optical channels carrying subcarrier multiplexing signals in a comprehensive way. The equations and models that describe the conversion process and the resulting harmonic and intermodulation distortions are obtained showing the superior performance of XPM over XGM in terms of secondand third-order distortion and contrast ratio. Experimental results for XGM-based wavelength conversion that confirm the results predicted by our theoretical models are presented, and finally, we consider the specific application of wavelength conversion of optical channels carrying full frequency plans such as that of cable television applications.

Experimental characterization of XGM-SOA-based wavelength converted SCM systems

We present for the first time, to our knowledge, second-order intermodulation distortion measurements of a wavelength converted subcarrier multiplexed system employing cross-gain modulation effect of a semiconductor optical amplifier. The experimental results are in agreement with predictions from our previously developed theoretical model.

Experimental demonstration of the continuous tuning of microwave photonic filters by sinusoidal modulation of the filter coefficients

We show the results of a technique to tune continuously the resonances of the microwave photonic filters are shifted by changing the weight of the optical taps. It improves the performance of the cited filters.

Cross-phase wavelength conversion of SCM signals: harmonic and intermodulation distortion analysis

We address the signal impairment arising in the form of harmonic and intermodulation distortion when a subcarrier multiplexed signal is subject to cross-phase modulation wavelength conversion in semiconductor optical amplifiers.

A new fibre optic sensor independent of temperature variations and fabricated with fibre Bragg gratings

We propose a new structure for sensing variations in the refraction index independent of fluctuations in temperature. The scope of applications is very wide and can be used to detect electromagnetic, biochemical and even radiation changes. Also, it can be applied to the telecommunications field.

A new interrogation system for a large number of strain sensors using fiber Bragg grating for application in residential buildings

A new interrogation system for a large number of strain sensors is presented. In the residential building sensor market some facts have to be dealt with: low cost, networks with a large number of sensors, reliability, passive devices, amongst others. We have accomplished all of these with the new interrogation system we are going to present.