共查询到20条相似文献,搜索用时 203 毫秒
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Application of genetic algorithm in quasi-static fiber grating wavelength demodulation technology 总被引:1,自引:0,他引:1
TENGFeng-cheng YlNWen-wen WUFei LIZhi-quang WUTi-hua 《光电子快报》2007,3(4):271-274
A modified genetic algorithm (GA) has been proposed, which was used to wavelength demodulation in quasi-static fiber grating sensing system. The modification method of GA has been introduced and the relevant mathematical model has been established. The objective function and individual fitness evaluation strategy interrelated with GA are also established. The influence of population size, chromosome size, generations, crossover probability and mutation probability on the GA has been analyzed, and the optimal parameters of modified GA have been obtained. The simulations and experiments, show that the modified GA can be applied to quasi-static fiber grating sensing system, and the wavelength demodulation preci- sion is equal to or less than 3 pm. 相似文献
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A novel fiber Bragg grating (FBG) current sensor with temperature compensation has been proposed. The fiber Bragg grating is glued on the surface of an isosceles triangle cantilever beam, which has a step thickness along the beam axis. Due to the electromagnetic force created by a solenoid and a permanent magnet mounted on the top of the beam, a step strain is applied on the fiber Bragg grating. The change of the electric current in the solenoid makes the spectrum of the fiber Bragg grating split. By monitoring the shift difference of the two split center wavelengths, which is related to the electric current in the solenoid, a current sensor with temperature compensation is obtained. The test range of 0-400 mA is achieved. The experimental results also show that the relationship between the shift difference of the two split center wavelengths of the FBG and the electric current has a linearity of 0.9937, and the sensitivity is about 2.64 nm/A; the test results are independent of the temoerature, so the cross sensitive problem is solved. 相似文献
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A simple structure optical fiber sensor for relative humidity (RH) and temperature measurement is proposed and verified in this paper, which is based on graphene oxide quantum dots and polyvinyl alcohol (GOQDs-PVA) composite coated tapered no-core fiber (NCF) combined with a fiber Bragg grating (FBG). FBG is insensitive to humidity and sensitive to temperature, which is used to compensate temperature of the sensor. Experimental results show this sensor has humidity sensitivity of 143.27 pm/%RH ranging from 30%RH to 80%RH and the temperature sensitivity of 9.21 pm/℃. The proposed sensor has advantages of simple structure, good repeatability, and good stability, which is expected to be used in both RH and temperature measurement in biological and chemical fields. 相似文献
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In present work, a hetero-junction of n-silicon (n-Si) with copper phthalocyanine (CuPc) has been fabricated. The current-voltage characteristics were investigated to explain the rectification and conduction mechanism. The effect of temperature and humidity on electrical properties of n-Si/CuPc hetero-junction has also been investigated. The characteristics of the junction have been observed to be temperature and humidity dependent so it is suggested that this junction can be used as temperature and humidity sensor. 相似文献
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A temperature sensor based on a switchable dual-wavelength fiber Bragg grating (FBG) laser with a semiconductor saturable absorber mirror (SESAM) is presented and demonstrated experimentally. The repetition rate of Q-switched pulses is ~17 kHz. The results demonstrate that the measured temperature has good linearity to the wavelength spacing of the two lasing wavelengths and has a temperature sensitivity of 21 pm/ºC covering a range of -10—22 °C. The experimental results prove the feasibility of the proposed temperature sensor. 相似文献
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An optical fiber sensor for strain and temperature measurement based on long period fiber grating (LPFG) cascaded with fiber Bragg grating (FBG) structure has been proposed and realized both theoretically and experimentally. Theoretical analysis shows that two microstructures with similar sensitivities cannot be used for double parameters measurement. The LPFG is micromachined by the CO2 laser, and the FBG is micromachined by the excimer laser. For the validation and comparison, two FBGs and one LPFG are cascaded with three transmission valleys, namely FBG1 valley at 1 536.3 nm, LPFG valley at 1 551.2 nm, and FBG2 valley at 1 577.3 nm. The temperature and strain characteristics of the proposed sensor are measured at 45—70 °C and 250—500 με, respectively. The sensitivity matrix is determined by analyzing wavelength shifts and parameter response characterization of three different dips. The proposed optical fiber sensor based on LPFG cascaded with FBG structure can be efficiently used for double parameters measurement with promising application prospect and great research reference value. 相似文献
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GAO Xue-qing JIANG De-sheng 《半导体光子学与技术》2006,12(4):233-237
Wavelength division multiplex has obvious advantages when it is used in fiber Bragg grating (FBG) sensing for simultaneous measurement of various quantities, but the number of sensors is usually restricted by the bandwidth of SLED and demodulator. The identical fiber Bragg grating is introduced for fire alarm system and the method of collecting signal of identical FBG sensors is described. The experiment result shows that with identical FBG sensing. The number of the sensors coupled in one fiber increases greatly and the precision can be ensured to meet the requirement for fire alarm system. 相似文献
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A grapefruit microstructure fiber temperature sensor coated with liquid crystal based on waist-enlarged taper 下载免费PDF全文
In this paper, a grapefruit microstructure fiber (GMF) temperature sensor coated with liquid crystal (LC) based on waist-enlarged taper is proposed and fabricated, and its temperature sensing characteristics are analyzed. The waist-enlarged taper is formed at the fusion point between single mode fiber (SMF) and GMF. The capillary glass tube is sleeved outside GMF, LC is filled into the capillary glass tube, and its two ends are finally sealed to form a sensor. The experimental results show that when the length of GMF is 2.5 cm, the temperature sensitivity of the sensor can reach up to 195.3 pm/°C in the range of 30—90 °C, and it has a good stability for reuse. Thereby, it can be used in biochemical, industrial production and other temperature detection areas. 相似文献
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In this paper we design a new kind of sinc-sampled fiber Bragg grating which is fabricated in high birefringence fiber (HBF). The sampled grating has two sets of reflection spectra along two perpendicular polarization directions. The grating’s channel number can be doubled approximately by designing the refractive index difference between the fast and slow axes of the fiber, which enhances the utilization ratio and reduces the claim for photosensitivity of the fiber. The group delay characteristics are theoretically studied and side-lobes are depressed by apodization as well to get the optimized spectra. The results show that the comb-like spectra of the grating have promising applications in both multi-wavelength polarized fiber lasers and fiber sensing networks. 相似文献
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A novel dual-wavelength fiber laser with asymmetric fiber Bragg grating(FBG) Fabry-Perot(FP) cavity is proposed and experimentally demonstrated. A couple of uniform FBGs are used as the cavity mirrors, and the third FBG is used as intracavity wavelength selector by changing its operation temperature. Experimental results show that by adjusting the operation temperature of the intracavity wavelength selector, a tunable dual-wavelength laser emission can be achieved. The results demonstrate the new concept of dual-wavelength lasing with asymmetric FBG FP resonator and its technical feasibility. 相似文献
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为提高光纤陀螺宽谱光源的平均波长稳定性,提出了一种用60μm超短光纤光栅制作带宽11.77 nm温度不敏感滤波器的方法。利用金属材料的热膨胀系数差,设计了双金属温度补偿结构,能够随温度的升高/降低对光纤光栅压缩/拉伸,有效地补偿光纤光栅由热光效应引起的波长变化。在30~60℃的温度范围内,光纤光栅的温度灵敏度系数为0.15 pm/℃,较未补偿前降低了60倍以上。该结构具有较好的温度不敏感性,可作为光源滤波器提高光源的平均波长稳定性并有望用于高精度光纤陀螺。 相似文献
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Zhang Xuezhi Chen Guanlong Jiang Junfeng Fan Xiaojun Liu Kun Wang Shuang Liu Yantao Ni Jingda Liu Tiegen 《激光与光电子学进展》2021,58(21):348-357
In this paper,a weak fiber Bragg grating (WFBG) based sensing system applied to the cryogenic static test of launch vehicle oxygen tanks has been developed and the results of an evaluation are reported.A customized sensor encapsulation and installation method allow for precise strain measurement at cryogenic temperatures.The reflection peaks of series-connected WFBGs with low optical loss are obtained,ensuring high system reliability in harsh environments.The experimental results show that the maximum full-scale error is less than 0.81% full-scale error.The temperature is as low as-193 ℃ during the test.This study also demonstrates a practical method in which WFBG can be used to obtain critical parameters for structural monitoring in a cryogenic environment. 相似文献
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光纤光栅传感器在现实应用中的一个主要问题是温度和应变的交叉敏感问题.介绍了光纤双光栅同步测量温度和应变的原理,设计了一个光纤双光栅温度、应变测量系统,对光纤双光栅的温度和应变传感性能进行了实验研究,结果表明光纤双光栅具有多参量同时测量的能力. 相似文献
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基于倾斜光纤光栅的温度不敏感振动传感器 总被引:1,自引:0,他引:1
提出了一种基于倾斜光纤光栅与多模光纤相结合的温度不敏感振动传感器,其振动传感头是在倾斜光纤光栅与单模光纤之间加入一小段多模光纤所组成。倾斜光纤光栅的反射光谱有布拉格模和包层模两部分组成,其中多模光纤的作用是将倾斜光纤光栅反射包层模耦合到单模光纤的基模。倾斜光纤光栅包层模对外界振动很敏感,通过传感器的包层模平均输出功率完成对外界振动物理量测量。由于采用强度解调的方式,可以大大降低传感器装置的复杂性。实验表明:当传感器温度从20 ℃上升到70 ℃时,传感器的输出平均光功率均方根误差为0.01 μW,其反射光谱平均输出功率影响很小,故可以避免外界温度对测量结果的影响。 相似文献
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有效的深海探测技术是获取海洋环境和资源信息的重要方式,也成为当前海洋领域内的研究重点,而海水温度是海洋探测研究关注的重要物理量之一。光纤光栅温度传感器凭借其独特的传感优势已广泛应用于航空航天、石油化工等领域,但对于海洋环境监测领域渗透较少。本文简述光纤光栅基本原理、结构及性能,并与传统测量方法进行比较,重点研究了近几年国内外光纤光栅温度传感器在海洋探测领域的最新研究进展,通过分析指出光纤光栅温度传感器是对现有传统海洋温度探测器的重要补充,在此基础上对于未来海洋光纤光栅温度传感器的研究方向提出了一些建议。 相似文献