共查询到20条相似文献,搜索用时 31 毫秒
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Jewart CM Chen T Lindner E Fiebrandt J Rothhardt M Schuster K Kobelke J Bartelt H Chen KP 《Optics letters》2011,36(12):2360-2362
This Letter presents simulation and experimental results of orientation-dependent transverse stress fiber sensors using fiber Bragg gratings (FBGs) inscribed in four-hole suspended-core fibers. Resonant peak shifts and splitting of FBGs were studied as functions of the applied transverse load and fiber orientation. Both simulation and experimental results revealed that the response of FBGs in suspended-core fibers is sensitive to both the orientation and magnitude of an applied transverse stress. 相似文献
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Experimental investigation of pre-irradiation effect on radiation sensitivity of temperature sensing fiber Bragg gratings
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The effect of pre-irradiation on radiation sensitivity of fiber Bragg gratings(FBGs) is verified experimentally.FBGs are fabricated in photosensitive optical fibers and single mode fibers with Ge-concentration in a range from 3 mol% to 23.37 mol% in the core.In experiments,the FBGs are subjected to twice γ-radiation exposures to a Co60 source at a dose-rate of 0.1 Gy/s up to a total dose of 50 kGy.Pre-irradiation treatment can reduce the temperature sensitivity variation of FBGs by 18.12%-35.91%,as well as Bragg wavelength shift(BWS) by 8%-27.08 %.Our research demonstrates that pre-irradiation treatment is a feasible method to improve the radiation tolerance of FBGs. 相似文献
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Sensing properties of fiber Bragg gratings in small-core Ge-doped photonic crystal fibers 总被引:1,自引:0,他引:1
Yiping Wang Hartmut Bartelt Reinhardt Willsch Michael Kautz Manfred Rothhardt 《Optics Communications》2009,282(6):1129-1134
We report about fiber Bragg gratings (FBGs) inscribed in two different types of small-core Ge-doped photonic crystal fibers with a UV laser. Sensing properties of the FBGs were systematically investigated by means of demonstrating the responses of Bragg wavelengths to temperature, strain, bending, and transverse-loading. The Bragg wavelength of the FBGs shifts toward longer wavelengths with increasing temperature, tensile strain, and transverse-loading. Moreover, the bending and transverse-loading properties of the FBGs are sensitive to the fiber orientations. The reasonable analyses for these sensing properties also are presented. 相似文献
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荧光光纤光栅传感特性的实验研究 总被引:2,自引:2,他引:0
在载氢掺铒光纤上写入Bragg光纤光栅,得到新型光子学器件-荧光光纤光栅.分别对其Bragg波长(λB)及荧光寿命(τ)的温度(T)及应变(ε)响应特性进行了实验研究,并且给出了λB和τ分别关于(T,ε)的拟合方程.实验结果表明:荧光光纤光栅的λB对T和ε的响应具备一般Bragg光纤光栅的优良特性,测得温度灵敏度为11.1pm /℃,应变灵敏度为1.19pm/με;而且τ对T和ε的响应也具有良好的线性关系,温度灵敏度为0.59 μs/℃,应变灵敏度为6.16 ns/με.实验结论为解决温度应力交叉敏感、实现温度应力的同时监测提供一条新颖的途径. 相似文献
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Vijay Janyani Ana Vukovic Trevor Benson John Paul Phillip Sewell 《Optical and Quantum Electronics》2007,39(9):709-716
Fibre Bragg gratings (FBGs) are an integral component of optical fibre based communication systems for signal processing.
Uniform FBGs and phase-shifted FBGs find major applications as add-drop filters in dense wavelength division multiplexing
(DWDM) systems where these are used to filter out channels and to shape the signal spectrum. We investigate numerically the
spatiotemporal deformation of pulses as they propagate through the gratings. In particular, the effect on the pulse dynamics
of phase shift or defect present in the gratings, often introduced intentionally in a grating to generate a narrow transmission
spike within the stopband, is studied in time domain. This study is of significance since the deformation in the pulse in
time limits the maximum bit rate achievable, and hence the pulse duration and shape need to be analysed and controlled accurately.
A time domain numerical tool based on the Transmission Line Modelling (TLM) method is developed to study the pulse dynamics.
The results obtained give useful information about the signal dynamics in gratings with defects, including the signal oscillations
trapped in the defect, to be considered in applications such as while designing spectral filters. 相似文献
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Irradiation effect on strain sensitivity coefficient of strain sensing fiber Bragg gratings
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The effect of irradiation on the strain sensitivity coefficient of strain sensing fiber Bragg gratings(FBGs) has been investigated through experiments. FBGs were fabricated in single mode fibers with 3 mol% Ge-concentration in the core and with a H2-loading treatment. In experiments, the FBGs were subjected to γ-radiation exposures using a Co60 source at a dose-rate of 25 Gy/min up to a total dose of 10.5 kGy. The GeO defect in fiber absorbs photons to form a GeE’ defect; the interaction with H2 is a probable reason for the γ-radiation sensitivity of gratings written in hydrogen loaded fibres. The effect mechanism of radiation on the strain sensitivity coefficient is similar to that of radiation on the temperature sensitivity coefficient. Radiation affects the effective index neff, which results in the change of the thermo-optic coefficient and the strain-optic coefficient. Irradiation can change the strain sensitivity coefficient of FBGs by 1.48%–2.71%, as well as changing the Bragg wavelength shift(BWS) by 22 pm–25 pm under a total dose of 10.5 kGy. Our research demonstrates that the effect of irradiation on the strain sensitivity coefficient of FBG is small and that strain sensing FBGs can work well in the radiation environment. 相似文献
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In this paper, the Yb-doped superfluorescent fiber source (SFS) with cascaded broad fiber Bragg gratings (FBGs) are reported. The spectral properties of this SFS with cascaded broad FBGs are described and compared with that without cascaded broad FBGs. The experimental results have shown that cascaded broad FBGs can increase the output of some special wave bands. 相似文献
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J. L. Yang S. C. Tjin N. Q. Ngo R. T. Zheng 《Applied physics. B, Lasers and optics》2005,80(4-5):445-448
A novel actively mode-locked multi-wavelength tunable fiber laser with equally increased or decreased wavelength spacing is presented. It is constructed using a double-ring cavity combined with an amplitude modulator and cascaded fiber Bragg gratings (FBGs). The cavity lengths for all FBGs are intrinsically identical due to the double-ring configuration, and simultaneous mode locking of multiple wavelengths is therefore achieved by applying only one mode-locking signal to the modulator. The FBGs are mounted on a organic plate with angles between adjacent gratings such that the forces applied to the FBGs have an equal force increment; thus, stretching or compressing the cascaded FBGs can achieve a wavelength tuning with equally increased or decreased wavelength spacing.This revised version was published online in March 2005. In the previous version, the published online date was missing 相似文献
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For the first time to the authors' knowledge, fiber Bragg gratings (FBGs) with >80 degrees tilted structures have been fabricated and characterized. Their performance in sensing temperature, strain, and the surrounding medium's refractive index was investigated. In comparison with normal FBGs and long-period gratings (LPGs), >80 degrees tilted FBGs exhibit significantly higher refractive-index responsivity and lower thermal cross sensitivity. When the grating sensor was used to detect changes in refractive index, a responsivity as high as 340 nm/refractive-index unit near an index of 1.33 was demonstrated, which is three times higher than that of conventional LPGs. 相似文献
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用紫外光直接在光纤内写入布拉格反射光栅的实验研究 总被引:2,自引:0,他引:2
用紫外光直接在光纤内写入布拉格反射光栅的实验研究杜卫冲谭华耀*刘颂豪华南师范大学,激光生命科学研究所,广州510631*香港理工大学,电机系自1989年Meltaz[1]首次提出采用两束波长位于掺Ge-石英光纤吸收带内的相干紫外激光相干涉,从侧面照射... 相似文献
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To model chirped fiber Bragg gratings (FBGs) for dispersion compensation in optical fibers a novel method of single expression
(MSE) is used. The reformulation of Helmholtz’s equation in the MSE to the full set of first-order differential equations
leads to dealing with the electric field amplitude, its derivative, power flow density and phase distributions in any aperiodic
media. The phase derivative obtained numerically permits to compute the dispersion slope in the time delay of investigated
chirped gratings. Reflective and time delay spectra of linearly chirped gratings of different lengths and chirp coefficients
are computed. A self-similarity law for the gratings of the same strength but different lengths and chirp coefficients is
revealed. The apodization of gratings is applied to reduce sidelobes in gratings’ reflection spectra and eliminate oscillations
in the time delay characteristics. 相似文献
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To model chirped fiber Bragg gratings (FBGs) for dispersion compensation in optical fibers a novel method of single expression (MSE) is used. The reformulation of Helmholtz's equation in the MSE to the full set of first-order differential equations leads to dealing with the electric field amplitude, its derivative, power flow density and phase distributions in any aperiodic media. The phase derivative obtained numerically permits to compute the dispersion slope in the time delay of investigated chirped gratings. Reflective and time delay spectra of linearly chirped gratings of different lengths and chirp coefficients are computed. A self-similarity law for the gratings of the same strength but different lengths and chirp coefficients is revealed. The apodization of gratings is applied to reduce sidelobes in gratings' reflection spectra and eliminate oscillations in the time delay characteristics. 相似文献
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Partha Roy Chaudhuri J.R. Panda H.N. Acharaya M. Dokhanian A. Sharma 《Optics & Laser Technology》2007,39(3):470-474
We report here the experimental realization of Fiber Bragg Gratings (FBG) of desired specifications in different application-types of in-house fabricated silica optical fibers, namely, standard telecom fiber of type SM-28, Er3+-doped SiO2–GeO2 fiber and photosensitive high GeO2 fiber. Fibers for this purpose were fabricated by customizing the process variables of the Modified Chemical Vapor Deposition (MCVD) technique used for our laboratory fabrication of optical fibers. To check the performance of the drawn fibers in terms of FBG characteristics, gratings were written by exposing a short length of fibers to interference fringes derived from a frequency-doubled Ar-ion laser using a modified two-beam interferometer system in single phase-mask configuration. Results of inscribing selected wavelength FBGs demonstrate the efficacy of our approach in achieving, reproducibly, high-quality FBGs in all application-fibers. 相似文献