1,721,289 research outputs found
Polarization properties of spun single-mode fibers
No full textSpun fibers are one of the most viable solutions to polarization mode dispersion. In this paper, their polarization properties are reviewed with special emphasis on randomly birefringent strongly spun fibers. The analysis is carried out by means of a new simplified model, which applies to a wide range of spin profiles that are either deterministic or random. It is shown that in general, a strongly spun fiber is characterized by an apparent random linear birefringence and an apparent deterministic circular birefringence. The latter term may originate unusual polarization properties; yet, in some cases of practical interest, it is equal to zero, and when this happens, the strongly spun fiber has the same statistical properties of an unspun one
Distributed polarimetric measurements for optical fiber sensing
No full textDistributed polarimetric measurements based on Rayleigh scattering in single mode optical fibers are effective tools for the characterization of the polarization properties of fibers. Since these properties are easily influenced by external perturbations, distributed polarimetric measurements turn out to be an interesting approach to distributed fiber optic sensors. This paper reviews the field putting emphasis on its underlying principles and unique applications, such as magnetic field mapping and twist measurement
Accurate distributed characterization of polarization properties in optical fibers
No full textThe main achievements recently obtained by reflectometric distributed characterization of fiber optic polarization properties are reviewed, with special emphasis on birefringence measurements. Experimental results on polarization effects induced by fiber geometry are also presented
Modal Dispersion Properties of Few-Mode Spun Fibers
No full textThe effects of spin on the modal properties of few mode fibers are numerically investigated showing that, at least in the cases considered here, the spin may even increase modal dispersion rather than decreasing it
Theoretical analysis of reflectometric measurements in optical fiber links affected by polarization-dependent loss
No full textThe theory of reflectometric measurements of polarization-dependent effects in optical fiber links is generalized to the case of links with polarization-dependent losses. The results are a clean generalization of the no-loss case. In particular, a new technique for the reflectometric measurement of the mean polarization-dependent loss is proposed. Furthermore, the possibility of characterizing the local birefringence and the local dichroism of the link is discussed
The exact statistics of polarization-dependent loss in fiber-optic links
No full textWe calculate the exact statistical characterization of the accumulated polarization-dependent loss (PDL) of an optical communication system. The results hold for any value of the PDL and, in the limit of low PDL, they agree with the approximate statistical description already reported in a previous letter. In particular, it is shown that the mean PDL grows at most linearly with the distance
Distributed Optical Fiber Sensing Based on Rayleigh Scattering
No full textOptical fiber sensors offer unprecedented features, the most unique of which is the ability of monitoring variations of the observed physical field with spatial continuity along the fiber. These distributed optical fiber sensors are based on the scattering processes that originate from the interaction between light and matter. Among the three different scattering processes that may take place in a fiber—namely Rayleigh, Raman and Brillouin scattering, this paper focuses on Rayleigh-based distributed optical fiber sensors. For a given optical frequency, Rayleigh-based sensors exploit the three main properties of light: intensity, phase and polarization. All these sensing mechanisms are reviewed, along with basic
principles, main acquisition techniques and fields of application. Emphasis, however, will be put on polarization-based distributed optical fiber sensors. While they currently represent a niche, they offer promising unique features worth being considered in greater detail
Measure of twist-induced circular birefringence in long single-mode fibers: Theory and experiments
No full textProduction defects and external perturbations cause standard telecommunication fibers to be randomly birefringent. Fiber birefringence is the origin of the well-known polarization mode dispersion (PMD), which degrades system performances. The knowledge of birefringence properties may be crucial, especially when problems like development of low-PMD fibers or PMD interaction with optical nonlinearities in very high-capacity systems are faced. Some techniques are known to measure birefringence, and useful results have been obtained for both installed and wound-on-drum fibers. However, measurement of the circular component of birefringence still presents difficulties. In this paper, a new method for circular birefringence measurement is proposed that applies to long single-mode twisted fibers. The technique is based on polarization-sensitive optical time-domain reflectometry. Experimental results are in good agreement with the theoretical analysis
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