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Search Results: 1 - 10 of 459 matches for " Bragg "
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Chalcogenide As2S3 Sidewall Bragg Gratings Integrated on LiNbO3 Substrate  [PDF]
Xin Wang, Aiting Jiang, Christi Madsen
Optics and Photonics Journal (OPJ) , 2013, DOI: 10.4236/opj.2013.31013

This paper introduces the design and applications of integrated As2S3 sidewall Bragg gratings on LiNbO3 substrate. The grating reflectance and bandwidth are analyzed with coupled-mode theory. Coupling coefficients are computed by taking overlap integration. Numerical results for uniform gratings, phase-shifted gratings and grating cavities as well as electro-optic tunable gratings are presented. These integrated As2S3 sidewall gratings on LiNbO3 substrate provide an approach to the design of a wide range of integrated optical devices including switches, laser cavities, modulators, sensors and tunable filters.

A Historical Narrative of Study of Fiber Grating Solitons  [PDF]
Xiaolu Li, Yuesong Jiang, Lijun Xu
Communications and Network (CN) , 2010, DOI: 10.4236/cn.2010.21006
Abstract: A brief historical narrative of the study of grating solitons in fiber Bragg grating is presented from the late 1970’s up to now. The formation of photogeneration gratings in optical fiber by sustained exposure of the core to the interference pattern produced by oppositely propagating modes of argon-ion laser radiation was first reported in 1978. One important nonlinear application of fiber Bragg grating is grating solitons, including gap soliton and Bragg soliton. This paper summarily introduces the numerous theoretical and experimental results on this field, each indicating the potential these solitons have in all-optical switching, pulse compression, limiting, and logic operations, and especially important for the optical communication systems.
The Use of Fiber Bragg Grating Sensors in Biomechanics and Rehabilitation Applications: The State-of-the-Art and Ongoing Research Topics
Ebrahim Al-Fakih,Noor Azuan Abu Osman,Faisal Rafiq Mahamd Adikan
Sensors , 2012, DOI: 10.3390/s121012890
Abstract: In recent years, fiber Bragg gratings (FBGs) are becoming increasingly attractive for sensing applications in biomechanics and rehabilitation engineering due to their advantageous properties like small size, light weight, biocompatibility, chemical inertness, multiplexing capability and immunity to electromagnetic interference (EMI). They also offer a high-performance alternative to conventional technologies, either for measuring a variety of physical parameters or for performing high-sensitivity biochemical analysis. FBG-based sensors demonstrated their feasibility for specific sensing applications in aeronautic, automotive, civil engineering structure monitoring and undersea oil exploration; however, their use in the field of biomechanics and rehabilitation applications is very recent and its practicality for full-scale implementation has not yet been fully established. They could be used for detecting strain in bones, pressure mapping in orthopaedic joints, stresses in intervertebral discs, chest wall deformation, pressure distribution in Human Machine Interfaces (HMIs), forces induced by tendons and ligaments, angles between body segments during gait, and many others in dental biomechanics. This article aims to provide a comprehensive overview of all the possible applications of FBG sensing technology in biomechanics and rehabilitation and the status of ongoing researches up-to-date all over the world, demonstrating the FBG advances over other existing technologies.
New approach to the strain analysis of bragg grating sensors
José R. Alves da Cunha,Petrus Alcantara Jr.,Angela Santa Brígida,Gilvan Borges,Jo o Weyl Costa
Photonic Sensors , 2013, DOI: 10.1007/s13320-012-0091-2
Abstract: The response of an optical strain sensor based on the fiber Bragg grating is theoretically analyzed with a different approach of that found usually in the literature. In this model, geometrical changes suffered by the grating itself are taken into account. The results are compared with those from experiments, showing very good agreement.
Estudo do poder de frenamento de partículas alfa na matéria
Fonseca, P;Zamorano, A;Luna, H;Santos, A.C.F;
Revista Brasileira de Ensino de Física , 2010, DOI: 10.1590/S1806-11172010000200005
Abstract: following the proposal of a quantum physics course with an experimental emphasis [p.r.s. gomes and t.j.p. penna, revista brasileira de ensino de física 10, 34 (1988)], in this work, we present a new simple method for the study of the stopping power of alfa particle in air, usually presented, when available, in advanced labs in physics and in medical physics courses. in this method, the bragg's curve can be obtained both qualitative and quantitatively.
Periodic Modulation of Nonlinearity in a Fiber Bragg Grating: A Numerical Investigation  [PDF]
Antonio Francisco Gomes Furtado Filho, José Rubens Rodrigues de Sousa, Apiano Ferreira de Morais Neto, Jose Wally Mendon?a Menezes, Antonio Sergio Bezerra Sombra
Journal of Electromagnetic Analysis and Applications (JEMAA) , 2012, DOI: 10.4236/jemaa.2012.42007
Abstract: We present numerical studies on the switching characteristics of a fiber Bragg grating (FBG) with modulation in the third order nonlinear index of refraction along it’s length. The FBG is operating in a continuous wave regime (CW). This study was done taking into account the possible asymmetry brought by the non harmonic modulation of the nonlinearity, leading to different reflection and transmission characteristics, that depend on the direction of propagation along the modulated nonlinear FBG. This phenomenon may be useful for applications like an optical isolator. It was found that for a set of values of the modulation parameter, the FBG can exhibit multistable states. The numerical studies were obtained starting from the coupled-mode equations solved from the coupled-mode theory and simulated using the fourth-order Runge-Kutta method.
A Smart Graded-index Multimode Fiber Based Sensor Unit for Multi-parameter Sensing Applications  [PDF]
Shuo Fang, Baoyong Li, Dawei Song, Jianzhong Zhang, Weimin Sun, Libo Yuan
Optics and Photonics Journal (OPJ) , 2013, DOI: 10.4236/opj.2013.32B062

We demonstrate a smart optical fiber sensor unit to realize a multi-parameter sensing, including temperature, curvature and strain or displacement. The sensor unit is composed of a Bragg grating in graded-index multimode fiber and a Fizeau cavity.

RETRACTED: What Is Wrong with Bohm’s Mechanics? An Analysis of a Hong-Ou-Mandel Type Experiment  [PDF]
Sofia Wechsler
Journal of Modern Physics (JMP) , 2016, DOI: 10.4236/jmp.2016.710097

Short Retraction Notice

The paper does not meet the standards of \"Journal of Modern Physics\". This article has been retracted to straighten the academic record. In making this decision the Editorial Board follows COPE's Retraction Guidelines. Aim is to promote the circulation of scientific research by offering an ideal research publication platform with due consideration of internationally accepted standards on publication ethics. The Editorial Board would like to extend its sincere apologies for any inconvenience this retraction may have caused. Editor guiding this retraction: Prof. Yang-Hui He (EIC of JMP).?

The full retraction notice in PDF is preceding the original paper, which is marked \"RETRACTED\".

All-Optical Frequency Modulated High Pressure MEMS Sensor for Remote and Distributed Sensing
Kasper Reck,Erik V. Thomsen,Ole Hansen
Sensors , 2011, DOI: 10.3390/s111110615
Abstract: We present the design, fabrication and characterization of a new all-optical frequency modulated pressure sensor. Using the tangential strain in a circular membrane, a waveguide with an integrated nanoscale Bragg grating is strained longitudinally proportional to the applied pressure causing a shift in the Bragg wavelength. The simple and robust design combined with the small chip area of 1 × 1.8 mm2 makes the sensor ideally suited for remote and distributed sensing in harsh environments and where miniaturized sensors are required. The sensor is designed for high pressure applications up to 350 bar and with a sensitivity of 4.8 pm/bar (i.e., 350 ×105 Pa and 4.8 × 10?5 pm/Pa, respectively).
Optical and electrical properties of Te doped AlGaAsSb/AlAsSb Bragg mirrors on InP
Toginho Filho, D. O.;Dias, I. F. L.;Duarte, J. L.;Laureto, E.;
Brazilian Journal of Physics , 2006, DOI: 10.1590/S0103-97332006000700023
Abstract: we present a comparative study carried out on the optical and electrical characteristics of undoped and te doped algaassb/alassb bragg mirrors with 6.5 pairs of layers and bulk undoped and te doped algaassb epilayers alloys lattice matched on inp, grown by molecular beam epitaxy, using sims, photoluminescence, reflectivity and ixv techniques. the temperature dependence of pl transitions observed in the bragg mirrors are similar to that observed in bulk samples and associated with the donor and acceptor recombinations in alloys with electrostatic potential fluctuations described by quasi-donor-acceptor-pair (qdap) models. we verified by sims the presence of a macro fluctuation in the te profile concentrations in the growth direction of the doped bragg mirror. the influence of doping, alloy and macrofluctuation of incorporated te on the optical and electrical properties of doped bragg mirror is analyzed. the algaas/alassb seems a very attractive option for vcsel technology.
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