1,721,022 research outputs found
Distributed characterization of few-mode fibers based on optical frequency domain reflectometry
No full textA novel technique to measure differential group delay and modal birefringence along few mode fibers is presented. The method relies on the analysis of the spectral correlation between two properly-selected sections of the fiber's Rayleigh-backscattered trace, acquired with an optical frequency domain reflectometer. Experiments performed on a two-mode-group fiber confirm the viability of the method
Distributed characterization of coupling in multimode and multicore fibers
Full text linkDistributed characterization of mode coupling is key to understanding the behavior of multimode and multicore fibers. This paper presents a theoretical framework that precisely assess limits and potentialities of mode-selective distributed measurements based on Rayleigh backscattering
Distributed measurement of birefringence in uncoupled multicore fibers
No full textWe report the results of the first distributed measurement of local birefringence performed on a nominally-uncoupled four-core fiber. The data show correlation between the intrinsic birefringence of the individual cores. (c) 2021 The Author(s
Improving the sensitivity of an interferometric fiber optic sensor for acoustic detection in rockfalls
No full textOptimization of an interferometric fiber optic sensor for ultrasonic acoustic detection in rockfall monitoring is addressed. The optimized sensor employs a polyimide coated fiber and improved design with an almost doubled acoustic sensitivity
Distributed optical fiber pressure sensors
No full textThe measurement of pressure by using distributed optical fiber sensors has represented a challenge for many years. While single-point optical fiber pressure sensors have reached a solid level of technology maturity, showing to be very good candidates in replacing conventional electrical sensors due to their numerous advantages, distributed sensors are still a matter of an intense research activity aimed at determining the most proper and robust pressure-sensitivity enhancement mechanism. This paper reviews early and recent works on distributed pressure sensors, classifying the sensors according to the sensing mechanism. For each type of mechanism, the issues and potentials are analyzed and discussed
Polarization-Dependent Phase of Light Propagating in Optical Fibers
Full text linkAs it propagates in a real single-mode fiber, light accumulates a phase delay and undergoes variations of its polarization state. These two phenomena are partly related to each other, owing to both well known geometric effects, i.e. the Pancharatnam's phase, and less known dynamic ones. This paper aims at reviewing these concepts, highlighting the polarization-depended phase of light that propagates in a single-mode fiber. We present a mathematical treatment using the familiar language of Jones and Stokes vectors and report experiments supporting the theory. The presented analysis has a general validity, and it can describe phase variation with respect to several parameters, such as distance, frequency and time. Its extension to multimode and multi-core fibers is also discussed. The results can be used for a better modelling and understanding of coherent transmission systems and interferometric fiber optic sensors
An Optical Fiber Distributed Pressure Sensing Cable with Pa-Sensitivity and Enhanced Spatial Resolution
No full textIn this paper, a high-sensitive, high-spatial resolution distributed pressure sensing cable employing standard single-mode fibers is presented and implemented. If measured with a distributed strain sensing interrogator with 1 μarepsilon resolution, the pressure resolution and accuracy demonstrated with this prototype are approximately 5 Pa and 10 hPa, respectively, with an intrinsic maximum spatial resolution of 8.5 cm. In terms of Rayleigh spectral shift, the sensitivity is about-30 GHz/kPa. Above all, the interrogation of the cable does not require an interrogator with such high spatial resolution, and the design is compliant with any optical fiber distributed strain sensing technique, such as Brillouin-and Rayleigh-based ones
Unidirectionally spun fibers for efficient narrow-band parametric amplification
No full textNarrow-band optical fiber parametric amplifiers realized by randomly bire-fringent and unidirectionally spun fibers are numerically studied. Fast spinning reduces random birefringence effects, enhances the gain and reduces gain fluctuations. © 2009 IEEE
Edge-carrier-assisted Phase-Retrieval Based on Deep Learning Enabling low CSPR and low Applied Dispersion Values
No full textWe explore the use of deep learning to loosen the constraints and enhance the performance of weak-carrier-assisted phase-retrieval receivers. The applied-dispersion-value can be reduced by 4-times and the complexity by 50% with low sensitivity penalties
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