共查询到18条相似文献,搜索用时 125 毫秒
1.
对相移长周期光栅进行了理论分析,在此基础上,运用传输矩阵法对它的透射光谱进行数值计算,分析了相移量大小、平均折射率变化以及光栅长度等结构参数变化对相移长周期光栅透射谱的影响,并根据这些变化规律适当调节它的结构参数,使其透射光谱与平坦EDFA的目标光谱在一定程度上相符。平坦后的EDFA增益谱在34nm范围内最大波动不超过±0.7dB。根据此方法设计的增益平坦滤波器只包含一个器件,体积小,便于制造和封装,具有很好的市场应用前景。 相似文献
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光子晶体光纤光栅反射谱及时延特性研究 总被引:2,自引:2,他引:0
利用多极法对包层空气孔为正六边形对称结构光子晶体光纤的模式场进行了分析,计算出不同波长下基模的有效折射率,结合使用模式耦合理论和传输矩阵法对基于光子晶体光纤的布拉格光栅特性进行了计算和仿真,对比了常规单模光纤所成光栅与相同光栅周期的光子晶体光纤布拉格光栅反射谱及时延特性之间的差异.在此基础上,对光纤光栅的切趾特性进行了研究,选择不同的切趾函数,得出最佳切趾函数下光栅传输谱.理论计算和仿真结果表明,随波长增加,基模有效折射率下降,光栅谐振波长出现蓝移,采用啁啾化处理后,10 cm长光子晶体光纤光栅可以提供1 200 ps以上的线性时延. 相似文献
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利用图解法求解光纤特征方程,获得腐蚀过程和传感过程中光纤光栅的光谱特性,设计了光纤光栅的部分腐蚀方案,采用氢氟酸溶液腐蚀制作相移布喇格光纤光栅。对光纤光栅进行部分腐蚀,将形成相移光纤光栅。根据相移光纤光栅的特性,讨论了利用反射光光强解调的方式,该方式具有结构简单且对温度不敏感的优点。 相似文献
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基于DSHI的窄线宽光纤激光器线宽测量 总被引:1,自引:0,他引:1
窄线宽光纤激光器的线宽作为相干光学系统的重要参数需要进行准确的测定,延时自外差法(DSHI)是测量窄线宽比较理想的方法.本文讨论了DSHI测量线宽的基本原理,根据DSHI的功率谱表达式,利用MATLAB程序对不同光纤延迟线长度条件下的DSHI功率谱进行了仿真,并分析和讨论了光纤延迟线长度对线宽测量结果的影响.建立了1550 nm波长的DSHI线宽测量系统,对IPG公司的光纤激光器线宽进行了测量.该系统用示波器代替频谱仪,并采用FFT软件算法对示波器获取的光电流信号进行分析,测得该激光器的线宽约为16 kHZ,在理想的精度范围内. 相似文献
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采用光束传播法(BPM),对单模-多模-单模(SMS)光纤结构内部传输光场分布情况,进行数值模拟;分析了SMS光纤结构中不同的多模光纤长度,多模光纤纤芯直径和输入光波长对光纤结构内部传输光场分布情况的影响,以及所得透射谱的变化规律;进一步探讨了基于多模干涉理论的SMS光纤结构传感器在各传感领域的应用潜力.最后,以基于多模干涉理论的SMS光纤结构折射率传感器为例,分析了多模光纤纤芯外界折射率的改变对光纤结构输出透射谱的影响,并进行实验加以验证.实验结果与仿真模拟结论一致,从而验证了模拟的准确性. 相似文献
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将啁啾莫尔光纤光栅看成一多层薄膜体系,每层薄膜用界面传输矩阵和膜层传输矩阵表示,将每层的传输矩阵相乘后得到光栅的传输谱。数值计算结果表明,啁啾莫尔光纤光栅的传输谱的通道数取决于啁啾莫尔光纤光栅的长度、两线性啁啾光栅的中心波长的差值;通道间隔和带宽取决于光栅的啁啾系数和折射率调制幅度。该模型的精度满足设计要求。 相似文献
7.
采用分层介质膜的等效模型,计算了均匀光纤栅及线性啁啾光栅的反射谱,透射谱及反射相位跃变,结构与采用耦合模理论计算的结果相吻合,表明这是分析光纤光栅的光反射特性的一种有效的新方法。 相似文献
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针对提高光纤光栅折射率传感器抗干扰能力以及增加反射率的需求,本文提出了一种基于Fabry-Perot腔的保偏微结构光纤(PM-MOF)布拉格光栅折射率传感器.根据传榆矩阵法和有限元方法,分析了微结构光纤光栅F-P腔中被测物折射率与F-P腔反射谱中两个偏振模谐振波长差的关系,在此基础上讨论了中心孔直径、F-P腔长度等参数对传输特性的影响.研究结果表明,随着空气孔中填充物折射率的增加,保偏微结构光纤光栅F-P腔的两个偏振态的谐振波长差将逐渐减小;F-P腔的干涉作用使反射率较单个光栅有很大提高,便于长距离传输和实时解调;两个偏振模对外界干扰具有相似的响应,因此该传感器具有更强的抗干扰能力.本文研究结果为保偏微结构光纤光栅在折射率传感器及其生物传感器方面的应用提供了理论依据. 相似文献
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AbstractTo manufacture fibre Bragg grating (FBG) transducer, finite element model simulation and experimental verification of packaging of the FBG by brazing/soldering were investigated. The packaging processes and their impacts on the wavelength change of FBG were analysed. Simulation results showed that the Bragg wavelength of packaged FBG shifted down a level of ~10 nm. For experimental verification, temperature sensitivity of the packaged FBG was enhanced about twice of the bare FBG, while its spectrum was well preserved. The Bragg wavelength was shifted down a level of ~10 nm which was in accordance with the simulation. 相似文献
12.
K. Thyagarajan 《Journal of Modern Optics》2013,60(14):1331-1339
AbstractIn this paper, we present the optical analogue of stimulated Raman adiabatic passage (STIRAP) technique for three level atomic system in optical fibre geometry. Considering linearly polarized modes of an optical fibre, it is shown that using a pair of superimposed long-period gratings with peak refractive index perturbation varying spatially along the propagation axis, light can be transferred adiabatically from one core mode to another core mode via an intermediate cladding mode which itself does not get appreciably excited; thus acting like a dark mode. We compare the transmission spectrum of superimposed long-period gratings involved in adiabatic transfer with the transmission spectrum of conventional long-period grating. The analogue output is further analysed for its tolerance to the changes in the ambient refractive index, temperature and other fabrication parameters. 相似文献
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Compensation of fibre dispersion-induced power fading in an externally modulated sub- carrier multiplexed radio-over-fibre transmission link using the chirped fibre Bragg grating (CFBG) has been investigated. The results show that periodic power fading caused by fibre chromatic dispersion is significantly reduced and the optimum transmission distance can be increased by proper design of grating parameters and optimum selection of apodisation profile. The investigation also reveals that carrier-to-noise ratio and bit-error rate of 156 Mbps DPSK signal are also significantly improved using the CFBG with asymmetric apodisation profile as the dispersion compensator. 相似文献
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针对光纤光栅传感领域波长高精度探测和传感复用光栅数量增多的需要,提出一种基于长信号相关谱的新型光纤光栅数字解调技术.该技术在可调谐滤波法的基础上,通过传感光栅与调制光栅反射谱卷积后的信号,即光电探测器的光强时间信号,进行自相关分析以实现对波长漂移的测量以及对传感光栅反射谱形状的识别,增强系统的复用能力,提高了性价比.模拟仿真表明,光纤光栅长信号相关数字解调方法可以准确测量光纤光栅波长的漂移,能更好实现传感复用.等强度悬臂梁实验验证该解调方法能实现光栅应变的高精度测量,优于传统的应变片测试. 相似文献
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设计了一种具有三层结构的亚波长金属光栅,采用时域有限差分(FDTD)法对所设计的三层光栅结构进行仿真计算.与单层金属光栅相比,这种三层的光栅结构具有更好的滤波效果,其透射光谱中峰值可达77%,且能很好地抑制高波段的透射率.分析了各几何参数对所设计的光栅结构透射特性的影响,尤其是对透射光谱中0值位置的影响.结果表明0值位置主要受光栅缝宽、介质层高度和介质折射率的影响,而与金属层光栅的高度无关.其影响规律为偏振滤波器的设计提供了参考. 相似文献
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Fusiek G. Niewczas P. Willshire A.J. McDonald J.R. 《IEEE transactions on instrumentation and measurement》2008,57(11):2528-2531
In this paper, we report on nonlinearity compensation for a solid-state fiber bragg grating (FBG) sensor interrogation system based on an arrayed waveguide grating (AWG) device. A lookup table with calibration data is used to improve system linearity. A reduction in the absolute value of the measurement error from 120 mustrain or 15degC to 4.8 mustrain or 0.6degC, respectively, is experimentally demonstrated. 相似文献
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A kind of compact fibre-optic sensor based on no-core fibre (NCF) cascaded with a strong coupling long-period fibre grating (LPFG) is proposed and experimentally demonstrated. The sensing mechanism is based on the Mach–Zehnder-like interference between the core fundamental mode and cladding mode of the fibre structure. The NCF and LPFG are used as the mode exciter and combiner, respectively. Due to the particular properties of the strong coupling LPFG, the measurements of refractive index (RI) and temperature with high sensitivity are realized by monitoring the transmission spectrum with intensity and wavelength interrogation techniques, respectively. The achieved RI sensitivity reaches ?580.269 dB/RIU in the range of 1.436–1.454 and the temperature sensitivity reaches 27.2 pm/°C. 相似文献