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1.
光纤布拉格光栅电流传感的理论和实验研究 总被引:8,自引:1,他引:7
对皮磁致伸缩棒调谐光纤布拉格光栅为基础的新型电流传感器进行了理论和实验研究。将一个光纤布拉格光栅牢固地粘贴在一置于多层螺线管中心部分的磁致伸缩棒上,构成传感头。当通过螺线管的电流改变时,磁致伸缩材料在均匀磁场的作用下产生沿纵向的应变并传递到光纤光栅上,从而导致光纤光栅的布拉格波长移动。外加电流和波长移动之间的关系是线性的,线性调谐的波长范围为0.9nm,电流强度范围为900mA,灵敏度约为1000mA/nm,电流强度可精确到10mA。理论和实验符合得很好。 相似文献
2.
In this contribution, an add/drop multiplexer that uses a mode-selective coupler and a holographically recorded slanted Bragg
grating in lithium niobate is demonstrated. A Bragg grating with a bandwidth of 0.1 nm allows for an add/drop efficiency of
about 96% with a cross-talk well above 22 dB applicable for wavelengths in the 1.5 μm window. Polarisation-independent operation
can be achieved by application of a bias electric field to compensate for the small mismatch of propagation constants of TE
and TM modes. The proposed scheme of an integrated-optical lithium niobate based device appears to be an interesting option
due to its potential for fast electro-optical switching.
PACS 42.40.Ht; 42.65.Hw; 42.70.Ln; 42.82.Cr; 42.82.Et 相似文献
3.
A chirped fiber grating with cladding made of uniaxial crystal material whose optical axis is parallel to the axis of grating,
i.e., z-axis is proposed. Electro-optic effect and elasto-optic effect in this kind of fiber gratings are theoretically analyzed
for the first time. The influences of the electric field and the strain applied to the fiber grating cladding along z-axis on Bragg wavelength λ
B and the reflectivity spectra of this kind of chirped grating are theoretically examined using coupled-mode theory and transfer
matrix method. The curves of Bragg wavelength λ
B as a function of an external electric field or the strain are theoretically obtained respectively for three kinds of uniaxial
crystal materials as the grating claddings. The calculated results indicate that when the axial electric field applied to
the grating cladding varies from 1 × 107 to 8 × 107 V/m, λ
B has the decreases of 0.12 nm, and when the applied strain varies from 0 to 0.04, λ
B has the decreases of 0.45 nm. 相似文献
4.
提出了以单轴晶体材料为包层,光轴平行于光栅主轴(z轴)的新型啁啾光纤光栅模型,应用耦合模理论和传输矩阵方法在理论上分析了该类光纤光栅中的电光效应和弹光效应,理论研究发现在包层施加沿光栅轴向的电场和应变场可以改变布拉格波长和反射谱。得到了3种不同单轴晶体为包层时布拉格波长λB和反射光谱随外加电场和应变场变化的曲线。研究结果表明当轴向外加电场从1×107V/m变化到8×107V/m时λB减小0.12nm,当外加应变场从0变化到0.04时,λB减小0.45nm。 相似文献
5.
Abstract This study proposed and demonstrated a fiber Bragg grating sensor for simultaneous detection of the temperature and refractive index of a liquid. The fiber Bragg grating is composed of three index layers: an inner core, an outer core, and a cladding. The cladding was etched for evanescent wave coupling between the outer core mode and an external liquid. The Bragg wavelength of the inner core mode is used for obtaining temperature data, while the refractive index for the liquid was determined by using the difference between the Bragg wavelength of the inner core mode and that of outer core mode. 相似文献
6.
Kerstin Schroeder Wolfgang Ecke Reinhardt Willsch 《Optics and Lasers in Engineering》2009,47(10):1018-1022
Fiber Bragg grating (FBG) sensors in single-mode optical fibers are widely applied for measurement of temperature and strain. If exposing FBG sensors to an external analyte by planar side-polishing technique of the fiber, evanescent-field interaction yields a Bragg wavelength shift also by changing the refractive index of the analyte. Deposition of sensor-specific transducer layers on the side-polished fiber can specify this spectrally encoding and network-capable optochemical fiber Bragg grating refractometry to the monitoring of specific substances, absorbed gases and vapors. In this paper, the sensor principle is demonstrated for the example of a hydrogen gas sensor based on a palladium thin-film transducer. Hydrogen in 0.1–4% volume concentration range can be monitored by the spectral shift of the Bragg wavelength, which is caused by the decreasing complex refractive index of Pd with increasing absorption of hydrogen. 相似文献
7.
A novel fiber Bragg grating (FBG) based chemical sensor using hydrogel, a swellable polymer, as sensitive element is demonstrated. The sensing mechanism relies on the shift of Bragg wavelength due to the stress resulted from volume change of sensitive swellable hydrogel responding to the change of external environment. A polyacrylamide hydrogel fiber grating chemical sensor is made, and the experiments on its sensitivity to the salinity are performed. The sensitivity is low due to the less stress from the shrinking or swelling of hydrogels. Reducing the cross diameter of the grating through etching with hydrofluoric acid can greatly improve the sensitivity of the sensor. 相似文献
8.
非轴向力下埋入式光纤传感器应变传递分析 总被引:2,自引:0,他引:2
利用剪滞法建立了当光纤光栅传感器的轴线和基体主应力的方向成一定角度时,光纤光栅传感器的测量应变与基体结构实际应变之间的关系,进而得出了光纤光栅传感器的平均应变传递率的一般公式。采用裸光纤光栅传感器进行实验,在倾斜角度α为30.72°时,实验所得的波长变化之比分别为:0.727,0.738,0.746;理论计算所得的波长变化之比为0.739,相对误差都在2%以内。同时分析了埋设角度偏差对测量结果的影响。研究结果表明,非轴向力作用下光纤光栅传感器的应变与结构基体应变之间的传递关系与其在轴向力作用下存在明显的区别,埋设角度的偏差会给测量结果造成一定的误差。 相似文献
9.
T. A. Moniem 《Fiber and Integrated Optics》2016,35(3):114-127
This article presents a methodology for an integrated Bragg grating using an alloy of GaAs, AlGaAs, and InGaAs with a controllable refractive index to obtain an adaptive Bragg grating suitable for many applications on optical processing and adaptive control systems, such as limitation and filtering. The refractive index of a Bragg grating is controlled by using an external electric field for controlling periodic modulation of the refractive index of the active waveguide region. The designed Bragg grating has refractive indices programmed by using that external electric field. This article presents two approaches for designing the controllable refractive indices active region of a Bragg grating. The first approach is based on the modification of a planar micro-strip structure of the iGaAs traveling wave as the active region, and the second is based on the modification of self-assembled InAs/GaAs quantum dots of an alloy from GaAs and InGaAs with a GaP traveling wave. The overall design and results are discussed through numerical simulation by using the finite-difference time-domain, plane wave expansion, and opto-wave simulation methods to confirm its operation and feasibility. 相似文献
10.
本文提出并论证了一种光纤光栅高速解调的新方法, 利用色散补偿光纤的色散效应, 将光纤光栅的波长漂移信息转换成时域信息. 采用脉冲激光器作为光源, 仅需一个光脉冲可获取单根光纤上所有光纤光栅的反射光脉冲, 再根据各个光栅反射回光脉冲的延时变化即可实现波长的解调. 本方法可用于准分布光纤光栅传感网络解调, 系统采用全光纤结构, 无需波长扫描, 大大提高了解调速度. 本文搭建了测试系统进行实验验证, 对3个光纤光栅组成的准分布式传感网络进行了解调, 实验结果表明, 解调出的光纤光栅布喇格波长线性度好, 解调速度最高可达1 MHz, 采样数据取10次平均后解调线性度可达0.9969, 解调误差约为27.8 pm. 相似文献
11.
Mosimann R Marty P Bach T Juvalta F Jazbinsek M Günter P Grabar AA 《Optics letters》2007,32(22):3230-3232
We demonstrated for what is the first time to our knowledge photorefractive two-wave mixing in a bulk ferroelectric crystal using cw light at the telecommunication wavelength 1.55 microm. In the Te-doped ferroelectric semiconductor Sn2P2S6 with absorption constant <0.1 cm(-1) at 1.55 microm, grating recording times of 10 ms and a two-beam coupling gain of 2.8 cm(-1) have been measured at 350 mW power (intensity 440 W/cm(2)) without a necessity to apply an external electric field. With a moving grating technique, a maximal gain of 6.0 cm(-1) has been obtained. 相似文献
12.
Daniel Alfredo Chamorro Enríquez Alberto R. da Cruz Maria Thereza M. Rocco Giraldi 《Optics & Laser Technology》2012,44(4):981-986
In this work, we propose a configuration of a hybrid fiber Bragg grating together with a long period grating sensor used for simultaneously detect surrounding refractive index and temperature to be applied in aqueous environment and to reveal pollution. We present the simulation of such sensor and analyze the reflected wavelength and amplitude variations of the fiber Bragg grating spectrum to obtain the temperature and the external refractive index variations, respectively. The results show that the fiber Bragg grating reflected amplitude change depends on the variation of the long period grating transmission spectrum with the surrounding refractive index modification and the reflected wavelength shift depends on the temperature of the aqueous solution. 相似文献
13.
A new method of distributed in-fiber Bragg grating sensing is proposed. A method is outlined by which the strain field imposed upon a Bragg grating sensor is obtained by measurement of the sensor's reflectivity and delay characteristics. The proposal is demonstrated by interrogation of two loaded samples. Strain distributions from these experiments are compared against a theoretical estimate. The data treatment is also discussed. Strain resolution is found to be +/-24 microepsilon, with a spatial resolution defined by a minimum spatial wavelength component of the coupling distribution of 1.65 mm. 相似文献
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15.
Temperature-insensitive strain measurement using differential double Bragg grating technique 总被引:1,自引:0,他引:1
A novel differential double Bragg grating sensor for temperature-insensitive strain measurement is presented. The sensor consists of two identical weak measuring and reference gratings separated by some distance. The reference grating is placed inside the silica capillary that made it almost strain insensitive. The basic idea in differential double Bragg grating sensor is to measure the energy of the oscillating term in the reflection spectrum of double Bragg grating structure. The normalized energy of the interference term depends on the pitch difference of the two gratings and does not change when pitch variations of both gratings are equal with temperature variation. Therefore, the normalized energy of the interference term can be used for the temperature-insensitive strain measurement. 相似文献
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18.
High-g accelerometer based on an in-fiber bragg grating sensor 总被引:1,自引:0,他引:1
Sylvain Thériault Kenneth O. Hill Francois Bilodeau Derwyn C. Johnson Jaques Albert Gédéon Drouin Alain Béliveau 《Optical Review》1997,4(1):A145-A147
An accelerometer based on an in-fiber Bragg grating sensor has been fabricated and demonstrated. The grating sensor operates linearly up to accelerations of 170,000gn. The design, testing and performance of the accelerometer are discussed. 相似文献
19.
A simplified ring cavity for achieving a unidirectional room temperature multi-wavelength erbium-doped fiber ring laser without optical isolator is demonstrated. The fiber ring cavity is built in such a way that the optical fields propagating in two directions suffer different losses caused by one sampled fiber Bragg grating. Furthermore, simultaneous multi-wavelength lasing with 0.8-nm intervals is demonstrated with sinusoidal phase modulation just before the sampled fiber Bragg grating to prevent single-wavelength lasing and unstable wavelength oscillation. 相似文献
20.
Experiments on slow/fast light propagation in the Bragg grating recorded in the optical waveguide formed in a photorefractive
copper-doped lithium niobate wafer are reported. The change from slow to fast light propagation in the 8-mm-long grating with
spectral FWHM of ≈0.14 nm and maximum Bragg reflection of ≈90% was achieved by tuning the carrier wavelength around the central
Bragg value of ≈1553.36 nm. Effective electrooptical control of the 80-ps pulse shift (fractional delay/advancement of up
to 0.4) was demonstrated by applying an external voltage of ≈80 V to the electrodes deposited on the waveguide sides. 相似文献