Papers by Keyword: Optical Fiber

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Authors: Kyoung Jin Kim, Ho Sang Kwak, Jin Su Choi
Abstract: In manufacturing optical fibers, there has been intense research efforts of continually increasing fiber drawing speed to improve productivity. However, higher speed fiber drawing poses new challenge in many areas of optical fiber manufacturing. In this paper, thermal effects on coating resin flow in an unpressurized coating applicator are studied numerically. Present simulation results found that higher fiber drawing speed leads to severe viscous heating in coating resin flow and significant increase of resin temperature, which in turn leads to substantial viscosity decrease. These thermal effects profoundly alter the resin flow patterns and velocity profiles in the coating die and they should be considered in controlling the final coating thickness.
Authors: Ying Chien Tsai, Guang Miao Huang, Jun Hong Chen, Inn Chyn Her
Abstract: The surfaces of the microlenses at the conical end-faces of optical fibers require high quality to keep the best performance of laser beam delivery. The polishing parameters play an important role to get the best quality of the microlenses. Most of the past researches study on the polishing parameters of flat surfaces. In this study, the polishing area of the conical end-face of the optical fiber is varied during fabrication. The relation between removed volume and removed thickness is built to determine the material removal rate. An experiment is carried out and the results show that the first two spinning turns are much effective for polishing under the parameters of the experiment.
Authors: Shu Hua Mo, Dong Yu, Guo Xing Wang, Li Xue Wang
Abstract: Microbending optical fiber pressure sensor is designed with the sensing unit based on multimode fiber in this paper. It consists of the pressure gasket, the microbending regulator and the metal clamp with fine adjustment structure. The measuring range of the sensor could be adjusted by choosing different gasket. When pressure acts on the fixture, a little displacement may occur, and luminous flux of the fiber will be lost after going through microbending part. According to the principle of light field detection, the pressure measurement can be achieved by detecting the loss of light intensity caused by different load. The basic structure of the sensor and its sensing mechanism are well introduced in this paper. In addition, for improving the effectiveness of the Microbending optical fiber pressure sensors, we set up mechanical zero adjustment and the maximal displacement limitation in order to avoid sensor breakdown caused by excess displacement.
Authors: Noella Evano, Rochdi El Abdi, Marcel Poulain
Abstract: During their use, optical fibers are subject to harsh installation and environmental conditions. To evaluate more precisely the lifetime of an optical fiber, it is necessary to study the mechanical behavior of optical fibers under extreme conditions, in particular under mechanical and thermal stress.This paper presents the results of new silica optical fibers aged in hot water between 20°C and 70°C and subjected to mechanical static bending stresses from 3 GPa to 3.5 GPa. Thermal dependence of the time to failure was observed. This dependence can be described by the Arrhenius model, where the activation energy is one of the main physical characteristic.
Authors: Jing Yi Wang, Yu Kun Bai
Abstract: In this paper, the difference of core-mode effective refractive indices (RIs) and the long-period fiber grating (LPFG) resonant wavelength in an uniaxial-crystal fiber resulted from two fiber analysis models were demonstrated and analyzed. The two models are two-layered medium model which is normally used for conventional single-mode optical communications fiber and three-layered medium model. Using Transfer Matrix Method (TMM) based on Coupled-Mode Theory (CMT), the different dispersion properties of chirped long-period fiber gratings (CLPFG) calculated by both models were compared. The result shows that the difference of the core-mode effective RIs is significant especially when the cladding radius and cladding mode order are small, which indicates the limitation of the two-layer model, and that reducing the cladding radius and increasing the cladding mode order can improve the CLPFG dispersion compensation capability effectively. This paper provides guidance to the design and accurate analysis of CLPFG based dispersion compensator (DC).
Authors: Dalibor Ciprian, Petr Hlubina
Abstract: Theoretical analysis of surface plasmon resonance ber optic sensor based on a core-shell nanoparticle layer is presented. The sensing structure consists of a standard step-indexmultimode optical ber whose bare fused silica core is coated by Ag core-shell nanoparticlemonolayer. Its optical constants were obtained using e ective media (Maxwell-Garnett) theory.Theoretical model based on thin- lm optics approach is used to compute the normalized powertransfer through the sensing part of the ber in spectral domain. The computed results areused to obtain the sensitivity and detection accuracy of the sensing scheme with respect tothe concentration of analyte components. The inuence of nanoparticle geometry on the sensorperformance is discussed.
Authors: Dian Hong Yu, Lin Li, Kai Zhao
Abstract: Based on the optical-wave’s theory, focusing energy transmission of UV radiation in rapid prototyping technology has been analyzed in depth. The reflecting focusing theory that continuous spherical wave radiated by point light source is reflected from concave ellipsoidal surface has been enucleated and the axial and lateral optical energy distribution of the reflecting optical wave field has been showed up. The analysis indicates that distribution of the intensity in optical axis is approximately Gauss distribution. And by means of experimentation, the research educes that the UV radiant energy being coupled by optical fiber and being focused by lens is approximately Gauss distribution, too. For effectively utilizing the UV radiant energy and improving the prototyping precision in rapid prototyping, the research supplies sufficient academic basis and has important guidance on the optical design of rapid prototyping.
Authors: Liang Nie, Jun Han, Xu Jiang
Abstract: The fiber point diffraction technology is applied in interferometer to measure optical surface with high precision. The wavefront diffracted from the single mode fiber with microns core diameter can be considered as ideal spherical wave and used as the referenced wave in interferometry. To estimate the quality of diffracted wavefront, the theoretical model of optical point diffraction is introduced at first. Based on the model, the influence of fiber core diameter, deformation and end-face shape on wavefront error is studied with numerical analysis. The analysis result shows that the single mode fiber used in experiment is available for instrument design and its influence over systematic error should be negligible within certain numerical aperture. Then a point diffraction interferometer with a single fiber is designed. Compared with the double fiber system, it has merit of noise immunity, high fringe contrast and high performance. Finally, the fiber point diffraction interferometer system is put up to measure spherical surface in experiment. The interference fringes are collected and analyzed with five-step shifting, least squares unwrapping and Zernike fitting method. The results show that the interferometer with optical fiber has achieved a worthy measurement precision and has great development potential.
Authors: Bao Ming Liu, Li Zhou
Abstract: This article introduces the basic concepts of optical access network, technical characteristics, the next type of optical access network applications, business support capabilities, configuration, structure, selection of future development trends of the optical access network.
Authors: Rochdi El Abdi, Alexandru Dumitrache Rujinski
Abstract: Fiber-optic sensors are mostly used for in situ measurements of diverse chemical composition of industrial surfactants employed in industry as detergents, emulsifying and dispersing agents, coatings, and pharmaceutical adjuvants. These optical sensors are often used in wet chemical environments in which the temperature can be high.The purpose of this work is to study the mechanical behaviour of optical fibers in contact with CetylTrimethylAmmonium Chloride in aqueous solution (CTAC) at different immersion durations and different temperatures.Optical fibers were submitted to dynamic bending test under different velocities.Result analysis demonstrates that immersion in CTAC drastically decreases the fiber strength particularly when immersed for long aging periods at high temperatures.
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