基于光子晶体光纤和单模光纤错芯结构的光纤传感器

制作了一种基于光子晶体光纤(PCF)和单模光纤( SMF)错芯结构的全光纤传感器。实验中,采用5cm的PCF,将其两端分别与SMF错芯熔接,制 成传感单元。第1个错芯结构将宽带光源的光分别耦合到PCF的纤芯和包层中,纤芯模式和包 层模式经过一定传输距离后进行SMF的纤芯,满足相位条件的发生干涉。在光谱仪(OSA)中观 测其干涉谱。当外界温度、折射率变化时,观测干涉峰位置的改变可实现对温度和折射 率的传感。实验结果显示,本文光纤传感器对温度的灵敏度为－8×10－3 nm/℃,对折射率的灵敏度为102nm/RIU。 对PCF填充乙醇后,制成相同结构的传感器,温度灵敏度达到－1.008nm/℃,提高了123倍。本文传感器制作简单,操作方便,能够广泛 应用于生物和物理传感领域。     

All fiber sensor based on Mach-Zehnder interferometer for simultaneous measurement of temperature and refractive index

In this paper, we propose and experimentally demonstrate a compact optical fiber sensor based on a Mach-Zehnder interferometer (MZI) cascaded with fiber Bragg grating (FBG) for simultaneous measurement of refractive index (RI) and temperature. In order to get a proper spectrum, we discuss the effects of different structure parameters of MZI. Using the resonant wavelength of the FBG (DipFBG) and the interference dip of the MZI (Dip1), the RI and temperature of the surrounding medium can be determined. The sensor has good operation linearity. The experimental results show that the distinctive spectral sensitivities are 0.071 75 nm/°C and ?91.766 67 nm/RIU (refraction index unit) for Dip1 and 0.009 09 nm/°C for DipFBG.     

正相高效液相色谱法检测火箭煤油中的芳烃

在ASTM6379标准方法的基础上,建立火箭煤油中芳烃的液相色谱-紫外检测方法。该方法采用氨基柱串联氰基柱,以正己烷为流动相,流速1.0mL/min,柱温28℃。单环芳烃以邻二甲苯计在8~80mg/L（r2=0.9999）范围内线形关系良好,定量限0.008mg/L,在已知浓度的样品溶液中分别加入高、中、低3种不同浓度的标准品溶液,回收率85.4%~114.1%,相对标准偏差小于5%。该方法简便易行、准确可靠。     

原子吸收法测定血清中多种微量元素含量

血清中微量元素含量直接反映机体中微量元素的代谢情况,在研究微量元素与健康关系时,常常把血清作为研究材料。但由于血清样品微量元素含量低且不能提供大量样品,用少量样品快速测定多个元素是个难点。为适应临床诊断多元素快速分析的需要,本文对血清中多种微量元素的测定方法进行了研究,根据所测微量元素的种类,结合使用火焰原子吸收法、微量脉冲进样－原子吸收法和石墨炉法,即可实现少量血清样品多种微量元素的测定工作。     

有毒有害和可燃气体的自动检测技术及其应用

本文综述了几种有毒有害及可燃气体的常用自动检测技术及最新进展,并对不同检测技术的检测特点和应用范围进行了对比。     

采用F-P光纤环滤波器的窄线宽环形腔光纤激光器

提出了一种采用F-P光纤环滤波器的窄线宽环形腔激光器,该激光器采用环形腔结构,两个耦合比为30:70的耦合器和一段2 m长的未泵浦掺铒光纤构成F-P光纤环滤波器,F-P光纤环滤波器产生的梳状谱,可以增大激光模式之间的自由光谱范围（FSR）,在一定程度上减小跳模现象的发生,有利于模式的稳定。研究表明,通过对掺铒光纤的优化和耦合器的选择可以提高F-P光纤环滤波器的精细度,而F-P光纤环中的未泵浦掺铒光纤起到饱和吸收体的作用,使输出激光的线宽得到有效压缩。将保偏光纤光栅和F-P光纤环滤波器共同应用于环形腔掺铒光纤激光器,在室温下得到了3 dB线宽均小于0.07 nm（实验室光谱仪最小分辨率）的窄线宽双波长输出。在2 h的观测时间内,最大峰值功率波动小于0.4 dB,具有良好的稳定性。     

Optical fiber magnetic field sensors with peanut-shape structure cascaded with LPFG

An optical fiber magnetic field sensor for the dual-parameter simultaneous measurement is proposed and demonstrated. The sensor head is constructed by a peanut-shape structure and long period fiber grating (LPFG) coated by magnetic fluid (MF). The external magnetic field intensity can be measured by the variation of characteristic wavelength (Dip1 and Dip2) in interference spectrum since the effective refractive index of MF changes with external magnetic field intensity. When the external magnetic field intensity changes from 0 mT to 20 mT, the magnetic field sensitivities of Dip1 and Dip2 are ?0.064 nm/mT and ?0.041 nm/mT, respectively. Experimental results show that the temperature sensitivities of the Dip1 and Dip2 are 0.233 nm/°C and 0.186 nm/°C, respectively. Therefore, the simultaneous measurement of the magnetic field intensity and temperature is demonstrated based on the sensitive matrix. It has some potential applications in aerospace, environmental monitoring and medical sensing fields.     

一种新型光纤光栅温度传感特性的实验研究

研制出一种具有微结构缺陷的新型光纤光栅,并对其温度特性进行了实验研究。该光栅是利用不同浓度的氢氟酸溶液对光纤布拉格光栅进行选择性刻蚀得到的,刻蚀区域改变了光纤的局部有效折射率,引入附加相移从而形成两个谐振峰。实验研究结果表明该新型光栅具有不同的温度灵敏系数,在20℃~90℃的温度范围内,随温度升高两谐振峰波长分别向长波方向移动了0.8127 nm和0.7329 nm,其温度灵敏系数分别为0.01161 nm/℃和0.01047 nm/℃,线性拟合度分别为0.991和0.998,新型光纤光栅两谐振峰随温度的变化呈现良好的线性关系。     

A dual-wavelength erbium-doped fiber laser with widely tunable wavelength spacing

A stable dual-wavelength erbium-doped fiber laser （EDFL） with tunable wavelength spacing and equalized output power is proposed and experimentally demonstrated. The fiber laser uses two fiber Fabry-Perot tunable filters （FFP- TFs） as the wavelength filter. The main cavity is divided into two sub-cavities with imbalance cavity losses through a 30/70 optical coupler. The tunable wavelength spacing can be achieved by changing the center wavelength of the filters and the equalized dual-wavelength output power can be achieved by properly controlling the variable optical attenuator （VOA） inserted in the lower-loss cavity.     

RAID服务器硬盘管理的风险防范

服务器中的数据资源存放在硬盘上,其安全重要性可想而知。本文旨在探讨服务器硬盘管理中的几个可能出现风险的环节,提出防范风险的一些应对措施。