相位敏感光时域反射计(Phase-sensitive Optical Time Domain Reflectometer,Φ-OTDR)是一种新型的分布式光纤传感技术,在周界安防入侵和建筑结构健康监测等领域具有广泛应用.针对Φ-OTDR的传感原理,根据其系统结构及信号处理,总结了Φ-...相位敏感光时域反射计(Phase-sensitive Optical Time Domain Reflectometer,Φ-OTDR)是一种新型的分布式光纤传感技术,在周界安防入侵和建筑结构健康监测等领域具有广泛应用.针对Φ-OTDR的传感原理,根据其系统结构及信号处理,总结了Φ-OTDR系统在光源技术、传感头技术、探测技术、复用技术和信号处理技术方面的进展,并对其进行了简要分析.展开更多
基于涡旋光纤(vortex fiber,VF)激发的柱矢量模式(cylindrical vector modes,CVMs)设计了迈克尔逊干涉仪传感器,并对轴向应变、温度和折射率传感特性进行了理论研究和实验验证。通过对VF施加一个微弯长周期光栅(microbend long period g...基于涡旋光纤(vortex fiber,VF)激发的柱矢量模式(cylindrical vector modes,CVMs)设计了迈克尔逊干涉仪传感器,并对轴向应变、温度和折射率传感特性进行了理论研究和实验验证。通过对VF施加一个微弯长周期光栅(microbend long period gratings,MLPG),激发一阶CVMs(TE01、HE21和TM01);在VF尾端加反射镜,反射后纤芯中的基本模式HE11与环芯中的CVMs产生干涉,构成了迈克尔逊干涉仪。实验测得对应于柱矢量模式TM01、HE21和TE01的应变灵敏度分别为-1.01 nm/mε、-1.61 nm/mε和-2.31 nm/mε,温度灵敏度分别为9.3 pm/℃,3.4 pm/℃和-2.4 pm/℃,而折射率不敏感。该传感器结构简单,且TE01模式具有最高应变灵敏度和最低温度灵敏度,可作为折射率不敏感的、温度交叉灵敏度低的理想无补偿应变传感器,是智能型工程结构中下一代传感器的理想选择。展开更多
We have demonstrated the highly efficient excitation of the linearly polarized mode(LP01)in ring-core fibers(RCFs)by tapering the spliced point between the RCF and the standard single-mode fiber(SMF)to optimize all-fi...We have demonstrated the highly efficient excitation of the linearly polarized mode(LP01)in ring-core fibers(RCFs)by tapering the spliced point between the RCF and the standard single-mode fiber(SMF)to optimize all-fiber orbital angular momentum(OAM)generation.The tapering technique has been investigated theoretically and experimentally.Before tapering,only 50%of light can be coupled from SMFs to RCFs.The modal interference spectrum with an extinction ratio(ER)of～9 dB is observed,showing that higher-order modes are excited in RCF.By tapering the spliced point,90%of light is coupled,and the ER is minimized to be～2 dB,indicating that the higher-order modes are effectively suppressed by tapering.Such tapered spliced points of RCF–SMF are further applied for all-fiber OAM generation.The efficiencies of OAM+1 and OAM?1 generation are found to be enhanced by approximately 11.66%and 12.41%,respectively,showing that the tapered spliced point of the RCF–SMF is a feasible way to optimize OAM generation.展开更多
文摘相位敏感光时域反射计(Phase-sensitive Optical Time Domain Reflectometer,Φ-OTDR)是一种新型的分布式光纤传感技术,在周界安防入侵和建筑结构健康监测等领域具有广泛应用.针对Φ-OTDR的传感原理,根据其系统结构及信号处理,总结了Φ-OTDR系统在光源技术、传感头技术、探测技术、复用技术和信号处理技术方面的进展,并对其进行了简要分析.
文摘为了研究耐高温胶的固化过程,基于光纤法布里-珀罗腔(F-P腔)传感器原理,将2根光纤的端面作为F-P腔的2个反射腔镜面,用耐高温胶将其封装入氧化锆陶瓷插芯内,制作了一个非本征型光纤F-P腔结构.通过6h谱形监测,发现耐高温胶在自然固化过程中使得F-P腔长变短,表明其在固化过程中收缩,最后趋于稳定,固化引入腔长的变化随时间呈现指数关系,时间常数(下降至1/e)约为40 min.
基金supported by the National Natural Science Foundation of China(Nos.61635006,61975108,and 61605108)the Shuguang Program(No.16SG35).
文摘We have demonstrated the highly efficient excitation of the linearly polarized mode(LP01)in ring-core fibers(RCFs)by tapering the spliced point between the RCF and the standard single-mode fiber(SMF)to optimize all-fiber orbital angular momentum(OAM)generation.The tapering technique has been investigated theoretically and experimentally.Before tapering,only 50%of light can be coupled from SMFs to RCFs.The modal interference spectrum with an extinction ratio(ER)of～9 dB is observed,showing that higher-order modes are excited in RCF.By tapering the spliced point,90%of light is coupled,and the ER is minimized to be～2 dB,indicating that the higher-order modes are effectively suppressed by tapering.Such tapered spliced points of RCF–SMF are further applied for all-fiber OAM generation.The efficiencies of OAM+1 and OAM?1 generation are found to be enhanced by approximately 11.66%and 12.41%,respectively,showing that the tapered spliced point of the RCF–SMF is a feasible way to optimize OAM generation.
