213 research outputs found
Liberali, cattolici e socialisti a Verona dalla fine dell’Ottocento al Fascismo
No full textAtti del convegno “Una città, un’industria, una famiglia: i Galtarossa” (tenutosi il 7.2.1997), organizzato da Associazione industriali e Osservatorio Provinciale del settore Metalmeccanico Fim Fiom Uilm di Veron
Beat length characterization based on backscattering analysis in randomly perturbed single-mode fibers
No full textThis paper presents analytical and numerical results on the statistical properties of the backscattering signal of a randomly perturbed, linearly birefringent, single-mode fiber. Our theory is based on the study of amplitude evolution of the backscattered field passed through a linear polarizer, aligned with the state of polarization of the input signal. In particular, we show that the mean value of the beat length can be calculated using two methods based, respectively, on a level crossing rate analysis of the backscattered signal and on the evaluation of the standard deviation of its spectral densit
Reflectometric measurement of polarization dependent loss in fiber optic links
No full textPolarization sensitive optical reflectometry is an effective tool for measuring birefringence and polarization mode dispersion of fiber optic links. Classical measurement techniques are based on the polarization analysis of the transmitted field, therefore they require access to both the ends of the optical link. Any typical optical link, made of a concatenation of optical single-mode fibers and optical devices, may be described with a Jones matrix F(z
Beat-length measurment in highly mode-coupled single-mode fibers by means of Fourier transform of backscattered signal
No full textAnalytical treatment of polarization-mode dispersion in single-mode fibers by means of the backscattered signal
No full textWe present analytical results on the polarization-mode dispersion characteristics of single-mode birefringent fibers based on statistical properties of the backscattered signal. In particular, we calculate exactly the relationship between polarization-mode dispersion characteristics in forward propagation with respect to round-trip propagation in terms of dynamical equations, differential group delays, correlation lengths, and second-order effects. The theory applies to fibers affected by superposition of linear and circular birefringence in both the short-length and the long-length regimes
Experimental investigation of polarization mode dispersion properties in single-mode fibers using a new backscattering technique
No full textA new technique based on backscattering technique is developed to determine the differential group delay (DGD), beat-length (LB) and correlation length (LC) to measure polarization-mode dispersion. A temperature-tuned distributed feedback (DFB) laser is used as an optical source and the optical signal is fully polarized by means of a fiber polarizer. An Er-doped fiber laser increases the dynamic range and followed by an optical filter to reduce spontaneous emission. The results indicated that the new technique is able to perform polarization characterization of long fiber using only one end, even when a strong polarization coupling affects the fiber
Polarization mode dispersion characterization of single-mode optical fiber using backscattering technique
No full textThis paper presents a completely new method able to characterize polarization mode dispersion (PMD) properties of randomly birefringent single-mode fibers, using polarization sensitive backscattering technique. We show analytical relationships between evolution of polarization state of backscattered signal with respect to state of polarization of forward one. Our technique allows one to measure differential group delay, beat length, and correlation length at the same time over long single-mode fibers using only one fiber end. Experimental data fit very well with numerical results, confirming the capability of our technique for fast routine characterization of PMD during cabling, before and after installation
Statistical description of optical system performances due to random coupling on the principal states of polarization
No full textWidely time-dispersion-tuned fiber optical oscillator and frequency comb based on multiple nonlinear processes
No full textAn all-fiber optical oscillator based on three nonlinear processes, namely stimulated Raman scattering and broadband
and narrow-band optical parametric amplification, is presented and experimentally characterized. The
wavelength tuning is achieved by means of the time-dispersion technique and spans over 160 nm. Through the same
technique a fast tunable optical frequency comb has been realized exploiting cascaded four-wave mixing
Misura in campo della dispersione di polarizzazione su fibre singolo modo per sistemi ad alta velocità
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