光子晶体光纤压力传感器光源方案设计

文章推导出PCF压力传感器检测基本原理,设计出PCF压力传感器典型系统结构,分析了PCF压力传感器对光源的特殊性能要求,选择半导体激光器(LD)作为传感器系统光源。提出LD工作稳定性整体控制设计方案,采用路分析方法给出LD中噪声控制模块、功率控制模块、温度控制制模块和波长控制系统。在LD中通过噪声、功率和温度控制等能够有效保障LD工作稳定性,保障PCF压力传感器系统对压力测量的精确性。     

填充混合液体的光子晶体光纤温度传感研究

为获得高灵敏度光子晶体光纤温度传感,在实心光子晶体光纤（PCF）空气孔中填充氯仿和酒精等高折射率热敏液体的混合物。理论上采用有限元法分析了温度对光纤模场面积和限制损耗的影响。通过调节液体的混合比,使损耗对温度的灵敏度达到最大值,实现了高灵敏度PCF温度传感。实验表明,填充液体的长为4mm的PCF温度传感器,灵敏度经检测...     

Ocean-bottom seismic observatories

Observations of seismic motion and other geophysical parameters on the ocean bottom over extended periods of time and over a wide range of frequencies (periods) provide information on the suitability of the ocean bottom as a site for the detection of seismic events. Instrument systems consisting of long- and short-period seismographs, long- and short-period pressure sensors, a temperature sensor, and a water-current sensor were operated on the ocean bottom. Experience and calculation indicate that these systems can be well coupled to the sediment surface, mechanically stable, and relatively insensitive to water currents. Local and distant earthquakes, tides, microseisms (3-8 seconds period), long-period (2-6 minutes period) pressure disturbances, and temperature fluctuations have been well recorded from the ocean bottom at depths greater than 2000 fm. Instrument systems were implanted at two locations: south of Bermuda (2400 fm depth, seismic measurements only) and west of San Francisco (2200 fm depth). Data were telemetered acoustically to a ship (Bermuda) and via deep-sea cable to a shore station (California). Results to date indicate that the ocean bottom can be a favorable location for the detection of seismic events.     

A new photonic crystal fiber gas sensor based on evanescent wave in terahertz wave band: design and simulation

In this paper, we present the design of a new photonic crystal fiber （PCF） gas sensor for evanescent-field sensing in terahertz （THz） wave band. This sensor can be used to identify the gas, and its size is very large, so that it is beneficial to fill it with the test substance. Based on simulation, we demonstrate that the gas sensor using PCFs with four noncir- cular large holes in the cladding has high sensitivity and low loss, the confinement loss is less than 0.007 dB/m, and the bending loss is very small. The new PCF gas sensor can detect kinds of gases, for example, if test gas is water va- por, it has obvious absorption peaks in THz band, and the sensitivities of gas sensor are 64% and 73% at 1.097 THz and 0.752 THz, respectively. Due to the ultra-low loss and high sensitivity of the model, the novel steering-wheel structured fiber is very suitable for evanescent-field sensing and the detection of chemical and biological products.     

Highly Sensitive Photonic Crystal Fiber-Based Refractive Index Sensing Using Mechanical Long-Period Grating

We experimentally demonstrate a novel refractive index (RI) sensor with the measurand infiltrated into the air channels of a single mode photonic crystal fiber (PCF). A tunable long-period grating is formed in a short length of PCF by use of the periodic mechanical pressure. Resonance shift with the change of the infiltrated liquid is observed with a sensitivity of ${hbox{4.1}} times {hbox{10}}^{-6}$ RI unit in a refractive index range from 1.32 to 1.39. The thermal stability of the pure-silica-based PCF device shows a three times better performance compared with conventional single mode fiber.      

High-sensitivity refractive index sensors based on fused tapered photonic crystal fiber

In this paper, a novel liquid refractive index (RI) sensor based on fused tapered photonic crystal fiber (PCF) is proposed. It is fabricated by fusing and tapering a section of PCF which is spliced with two single-mode fibers (SMFs). Due to the fused biconical taper method, the sensor becomes longer and thinner, to make the change of the outside RI has more direct effects on the internal optical field of the PCF, which finally enhances the sensitivity of this sensor. Experimental results show that the transmission spectra of the sensor are red-shifted obviously with the increase of RI. The longer the tapered region of the sensor, the higher the sensitivity is. This sensor has the advantages of simple structure, easy fabrication, high performance and so on, so it has potential applications in RI measurement.     

动态压力光子晶体光纤传感器的研究

光子晶体光纤传感器可广泛用于各种动态压力测量中.文章设计了一种动态压力光子晶体光纤传感器,采用差分平衡方法分析了这种传感器的压力作用原理,讨论了这种传感器的输出信号检测方案,结果表明,该传感器对外界压力作用的响应具有周期性,响应周期与外界压力和传感器敏感元件长度相关.     

基于SPR效应的金-PDMS涂覆光子晶体光纤高灵敏度温度测量

通过在光子晶体光纤(PCF)包层外侧填镀金纳米膜及PDMS温敏薄膜,设计了一种基于表面等离子体共振(SPR)效应的高灵敏度温度传感器,具有结构简单、工艺成熟、可逆性好的优点。PDMS的有效折射率会随温度的增加而减小,从而引起纤芯模式的损耗峰向短波方向移动。在完全匹配层边界条件下,利用全矢量有限元法分析SPR-PCF的损耗谱特性,实现了温度的高灵敏度精确快速测量。在22~47℃的温度范围内,所提传感器的温度灵敏度可达到-8.18 nm/℃,这种传感测量方法能拓展应用于各类安全检测和智能监测领域。     

亥姆霍兹光声光谱多气体检测器设计和优化

光声光谱技术作为一种先进的光学检测技术,已成功应用于各种痕量气体检测场合。实现多气体的光声光谱检测,同时保证高的检测灵敏度是检测器设计的核心目标。针对测量需求设计,优化了一种基于亥姆霍兹共振的光声光谱多气体检测器,使用有限元分析方法对检测器进行了设计和仿真分析,对光声池的结构参数以及温度和压力特性进行了优化和分析。仿真结果表明:对光声池结构参数进行优化和对温度压力进行控制可以提高检测器检测灵敏度;采用光源IR-19时,激发腔38 mm9 mm,连接管5.9 mm10.2 mm和探测腔30 mm5.8 mm为光声光谱检测器的最优化参数。经实验验证,检测器对CO气体的检测精度达到5.08 ppm（1 ppm=10-6）。研究结果为痕量多气体的光声光谱检测提供了设计参考。     

MEMS电容式压力传感器检测电路比较研究

介绍了MEMS电容式压力传感器检测电路的5种实现方式:脉宽调制法、运算放大器法、电荷注入法、调频法和AC运放法。并从稳定性、测量灵敏度及抗杂散性等方面介绍了不同方式下检测电路的优缺点,为MEMS电容式压力传感器提供了参考。     

掺杂型双芯光子晶体光纤高灵敏声压传感结构

为了解决石英材料高杨氏模量对光纤传感器均匀径向上灵敏度提升的限制,提出一种掺杂型双芯光子晶体光纤传感结构。该设计将圆形空气孔分列在光纤包层上,构成六边形晶格,在其单侧空气孔环绕的基材区域掺入聚甲基丙烯酸甲酯材料。利用COMSOL分析了均匀应力作用下光纤截面参量对声压灵敏度的影响,得到最优参量匹配结构。结果表明, kPa量级的声压作用下,自由光谱宽度约13nm; MPa量级的声压作用下,自由光谱宽度约2.5465nm, 在1550μm波段下,x偏振声压灵敏度达0.15942nm/kPa; 相比Saganc光子晶体光纤压力传感器,传感尺寸小,均匀径向灵敏度提高了46.6倍。该研究对下一代水下声压传感器的设计有帮助。     

高频CO2激光脉冲写入PCF-LPFG传感特性研究

采用高频CO2激光技术在柚子型光子晶体光纤(PCF)上写入长周期光纤光栅(LPFG),并对其温度、应变和弯曲特性进行了实验研究。实验测得,PCF-LPFG谐振波长的温度和应变灵敏度分别为0.002nm/℃和0.001 8nm/με,谐振峰损耗值对温度和应变不敏感。由于高频CO2激光写入为单侧写入,导致PCF-LPFG透射谱的弯曲特性与方向和曲率直接相关。选择弯曲灵敏度较大的方向进行了弯曲测试,测得在一定的曲率范围内,PCF-LPFG的谐振波长及谐振峰损耗值的灵敏度分别为-5.45nm/m-1和3.32dB/m-1。基于PCF-LPFG的透射谱温度不敏感特性,本文为制作不受温度影响的应变和弯曲传感器提供了新的方法。     

反射式掺杂液晶光子晶体光纤电场传感实验研究

提出了一种反射式结构的掺杂向列液晶(NLC)光子晶体光纤(PCF)电场测量传感器。传感器由小于1cm长的掺入液晶实芯PCF构成,在掺杂光纤端面镀Ag膜以提高端面反射率。通过实验,测量出了反射光强随电场强度增加的变化情况,证实了设计的传感器可以用于电场在1.4～3.7kVrms/mm范围内的电场测量,同时获得了镀膜对反射光强的影响以及对传感器灵敏度、精度的影响。     

基于强度检测的HiBi-PCF-FLM温度不敏感应力传感器

提出一种基于强度检测的高双折射光子晶体光纤环镜(HiBi-PCF-FLM,highly birefringent photonic crystal fiber loop mirror)温度不敏感应力传感器。利用PCF对温度的不敏感性,把一小段HiBi-PCF传感光纤插入到FLM中,可实现温度不敏感应力传感。利用应力作用引起FLM透射光谱移动的特性,由DFB激光作为入射光源,使用光功率计检测经过FLM后的透射光强度,实现基于强度检测的应力传感。当输入波长为1547 nm时,作用于PCF应力与经过FLM后透射光强度的关系可拟合为二次函数,其与实验数据的拟合度高达0.9995。     

微弯压力光子晶体光纤传感器的设计

光子晶体光纤(PCF)具有压力敏感特性.文章根据弹光理论推导了PCF应变与应力的关系,得到压力作用下PCF折射率分布波动的定量关系,提出一种微弯压力PCF传感器的设计方案,并从理论上分析了压力存在条件下光脉冲在PCF中传播时的相位波动及这种传感器的检测原理.     

Seawater temperature and salinity sensing based on in-fiber Michelson-Fabry-Perrot hybrid interferometer employing frequency domain decomposition method

We propose an in-fiber Michelson-Fabry-Perrot (M-FP) hybrid interferometer for the simultaneous measurement of seawater temperature and salinity. The sensor head consists of two parallel hetero Fabry-Perot (FP) cavities fabricated on the end face of the twin core fiber (TCF). A fiber fusion taper is used to split and recouple the light in the two cores. In this case, the Vernier effect can be obtained which can greatly enhance the sensitivity and solve the problem of temperature cross-sensitivity. Different from the traditional demodulation method based on envelop detection, we employed frequency domain decomposition method (FDDM) to demodulate the sensing signal. The simulation results indicate that the proposed sensor has high sensitivity to salinity and temperature. Thanks to the merits of high sensitivity, ease of fabrication and small footprint, the proposed seawater temperature and salinity sensor would have potential applications in marine science, food industry and ocean ranching.     

星载合成孔径雷达遥感海洋风场波浪场

星载合成孔径雷达(SAR)能够全天时、全天候、高空间分辨率、宽刈幅观测海洋表面，是获取海面风场和波浪场信息的重要微波传感器。该文综述了多极化SAR海面风场遥感原理、地球物理模式函数，以及潜在应用(海气边界层现象、海上风能资源开发、台风监测与预警预报)，系统总结了传统星载SAR、新型干涉和极化SAR海浪遥感方法和技术。随着雷达卫星编队飞行技术的逐步成熟，未来海洋卫星组网将成为全球海洋和极地观测新趋势，合成孔径雷达海面风场和波浪场定量遥感将从科学研究向业务化海洋动力环境监测发展。      

Design and test of a high-resolution acquisition system for marine seismology

Active and passive seismology require high-resolution, low-level signal acquisition. In both methods, the equipment most widely used to acquire seismic data in the marine environment is an ocean bottom seismometer (OBS). We designed and built a high-resolution acquisition system prototype for an OBS that is mainly used in active seismic experiments in which maps are generated of the width and material of ocean bottom sublayers. Other OBS system applications, in which the objective is to estimate the location and magnitude of an earthquake require higher autonomy. When an OBS is used in a permanent seafl oor observatory with no power supply limitation, it can generate tsunami alert signals to shore.     

采用聚酰胺酸层的高灵敏度长周期光纤光栅温度传感器

设计并论证了一种高灵敏度的长周期光纤光栅（LPG）温度传感器。将LPG的包层腐蚀,封装进金属外壳使LPG保持恒定拉力,再密封进盛满聚酰胺酸（PAA）的试管中,其中聚酰胺酸热光系数较大,作为感温材料。测试并讨论了使用不同折射率的聚酰胺酸与不同包层直径的LPG时,LPG共振波长随温度变化的漂移。结果显示,对于一个直径已知的特定LPG,当使用较大折射率的聚酰胺酸时,LPG温度传感器的灵敏度变高。对于使用相同折射率聚酰胺酸的LPG,随着LPG的包层直径减小,LPG温度传感器的灵敏度变高。实验制作的LPG温度传感器的灵敏度为1.26 nm/℃,约为普通LPG制作的传感器的10倍,以及普通FBG制作的传感器的100倍。这种新传感器在2~35℃线性度为99.80%,这提高了传感器的潜在应用,特别是在生物医学检测,海洋监测等这些温度范围接近室温的领域。