نتایج جستجو برای: fbg

تعداد نتایج: 2228  

2017
Bo Jin Weifang Zhang Meng Zhang Feifei Ren Wei Dai Yanrong Wang

In order to monitor the crack tip propagation of aluminum alloy, this study investigates the variation of the spectrum characteristics of a fiber Bragg grating (FBG), combined with an analysis of the spectrum simulation. The results identify the location of the subordinate peak as significantly associated with the strain distribution along the grating, corresponding to the different plastic zon...

Journal: :Scientific reports 2016
Jun He Yiping Wang Changrui Liao Chao Wang Shen Liu Kaiming Yang Ying Wang Xiaocong Yuan Guo Ping Wang Wenjing Zhang

We demonstrate a method for the preparation of negative-index fibre Bragg gratings (FBGs) using 800 nm femtosecond laser overexposure and thermal regeneration. A positive-index type I-IR FBG was first inscribed in H2-free single-mode fibre using a femtosecond laser directed through a phase mask, and then a highly polarization dependant phase-shifted FBG (P-PSFBG) was fabricated from the type I-...

2012
Zhiyong Zhang Lianshan Yan Wei Pan Bin Luo Ping Wang Likang Guo Wei Zhou

In strain measurement applications, the matched fiber Bragg gratings (FBG) method is generally used to reduce temperature dependence effects. The FBG parameters have to be designed to meet the requirements by the particular application. The bandwidth and slope of the FBG has to be balanced well, according to the measurement range, accuracy and sensitivity. A sensitivity enhanced strain demodula...

2011
Hiroshi Tsuda

An optical filter is incorporated in a conventional ultrasound detection system that uses a fiber Bragg grating (FBG) and broadband light source, to demodulate the FBG sensor signal. A novel ultrasound sensing system that does not require an optical filter is presented herein. Ultrasound could be detected via the application of signal processing techniques, such as signal averaging and frequenc...

2004
K. C. Chang T. K. Lin

Experimental result of a full scale-steel frame with a smart active control system under shaking table test has been carried out in this paper. Newly, the concept of smart structure has been broached to the extent of structure control. The NEURO-FBG control system, which is composed of both neural networks and fiber Bragg grating sensors, has been theoretically analyzed and simulated to effecti...

2011
Chien-Hung Yeh Chi-Wai Chow Ping-Chun Wu Fan-Gang Tseng

A novel fiber Bragg grating (FBG)-based passive sensor architecture, which can be used to protect the fiber cut and monitor the multiple sensors simultaneously, is proposed and experimentally demonstrated. Here, we employ a wavelength-tunable erbium-doped fiber (EDF) laser scheme with 25 km cavity length acting as the detecting light source in central office (CO). Each FBG sensor, serving as a ...

2009
Chang-Sun Hong

Fiber optic sensors have many advantages such as ease of embedding, flexible sensor size, wide temperature range, high sensitivity and etc[1]. Thus, fiber optic sensors have been introduced into many composite structures. Especially, FBG (Fiber Bragg Grating) strain sensors have noticeable attractions due to multiplexing capability, linear response and absolute measurement [2]. However, the use...

2007
Chang-Sun Hong Chi-Young Ryu

Fiber Bragg grating (FBG) sensors based on the wavelength division multiplexing technology are ideally suited for structural health monitoring. In many applications, it is desirable to form several arrays of optical fiber sensors to monitor the response of structures. In the present study, we constructed an improved FBG sensor system using a wavelength-swept fiber laser which exhibits high outp...

Journal: :Optics express 2013
Juan Sancho Sanghoon Chin David Barrera Salvador Sales Luc Thévenaz

A new technique to investigate the spatial distribution of the reflection spectrum along fabricated long weak fiber Bragg gratings (FBG) is experimentally demonstrated, together with its potential applications for distributed fiber sensing and broadband signal processing. A short pulsed coherent light signal is launched into a FBG and the signal frequency is scanned through the FBG reflection s...

2010
Jian-Neng Wang Jaw-Luen Tang

This paper presents the feasibility of utilizing fiber Bragg grating (FBG) and long-period fiber grating (LPFG) sensors for nondestructive evaluation (NDE) of infrastructures using Portland cement concretes and asphalt mixtures for temperature, strain, and liquid-level monitoring. The use of hybrid FBG and LPFG sensors is aimed at utilizing the advantages of two kinds of fiber grating to implem...

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