240Mbit/s直线运动型无线光通信系统研究

详细分析了直线轨道上运动通信的特点,设计和研制了一种具有双向收发功能的直线运动型无线光通信系统。该系统主要包括1 550 nm半导体激光器、高灵敏度PIN光探测器、球面单透镜式光发射天线和实心光锥耦合式光接收天线等关键部件。130 m运动工作距离的系统性能测试结果表明,在3.5 m/s最高运动速度、240Mbit/s通信传输速率下,运动中的数据丢帧率为零,以太网和视频指标均满足实际应用要求,系统适用于存在直线运动轨道的无线光通信场合。     

A temperature sensor based on the splicing of a core offset multi-mode fiber with two single mode fibers

In this paper, a temperature sensor based on the splicing of a core offset multi-mode fiber with two single mode fibers is proposed and demonstrated experimentally. The temperature sensing principle is analyzed and related experiment is performed. By controlling the core offset and splicing length of the specialty multi-mode fiber (SMMF), two sensors with different temperature sensing properties are obtained, and experimental results show that the temperature sensitivity can be up to 48.76 pm/°C in the range of 25—95 °C. Moreover, it has many advantages, including small size, high sensitivity, and simple structure. So it can be used in potential temperature sensing applications, such as industrial production, biomedical science, power electronics, and so on.     

Miniature Fabry-Perot interferometric sensor for temperature measurement based on photonic crystal fiber

A novel miniature Fabry-Perot interferometric (FPI) temperature sensor is proposed and demonstrated experimentally. The modal interferometer is fabricated by just splicing a section of photonic crystal fiber (PCF) with a single-mode fiber (SMF). The air holes of the PCF are fully collapsed by the discharge arc during the splicing procedure to enhance the reflection coefficient of the splicing point. The transmission spectra with different temperatures are measured, and the experimental results show that the linear response of 11.12 pm/°C in the range of 30–80 °C is obtained. This sensor has potential applications in temperature measurement field.     

Broadband quasi-phase-matched second-harmonic generation in MgO:LiNbO3 waveguide

The quasi-phase-matched(QPM) condition of broadband second harmonic generation(SHG) in Ti-diffused MgO:LiNbO3 waveguide is theoretically simulated.The results show that the center wavelength of broadband SHG dependent on the waveguide width is around 1550 nm and the bandwidth is 50 nm.     

待熔光子晶体光纤中的热传导特性

在光子晶体光纤(PCF)的熔接过程中,由于包层空气孔结构的存在,同在熔接过程中存在着潜在的空气孔形变,使得加热过程更为复杂.对待熔的光子晶体光纤的热传导特性进行了研究,以二氧化碳激光作为熔接热源,根据传热学及能量守恒定律建立三维对称的热传导模型,进而对光子晶体光纤熔接的瞬态传热过程进行仿真分析和实验研究.分析表明,该模型可以很好地确定影响光子晶体光纤熔接过程中热传导特性的各个主要因素,为最终确定最佳熔接条件建立理论基础.     

基于SFLA-LSSVM算法的多峰Brillouin散射谱的特征提取

提出了一种利用混合蛙跳算法(SFLA)优化最小二乘支持向量机(LSSVM)算法的混合优化算法,并将其应用到多峰Brillouin散射谱的特征提取中。SFLA-LSSVM混合优化算法利用SFLA对LSSVM算法中的惩罚因子C和核函数中的核宽度σ进行寻优,避免了LSSVM算法陷入局部最优导致的Brillouin频移误差较大。通过对相同信噪比、不同线宽以及相同线宽、不同信噪比2种情况下的多峰Brillouin散射谱仿真分析以及实验验证,拟合适应度为0.0067,拟合度为99.99%,Brillouin频移误差为0.18 MHz。实验结果表明SFLA-LSSVM混合优化算法能够精确地对多峰Brillouin散射谱进行拟合,同时该算法具有拟合精度高、均方误差小、运行速度快的特点,为多峰Brillouin散射谱的特征提取提供了一种新方法。     

A tension insensitive PbS fiber temperature sensor based on Sagnac interferometer

In this paper, a tension insensitive PbS fiber temperature sensor based on Sagnac interferometer is proposed and demonstrated. The sensing mechanism of tension and temperature is analyzed. The relationships between the interference spectrum, temperature and tension are analyzed, respectively. The experimental temperature range is 36—70 °C. The experimental results show that the interference spectrum is red shifted, and its sensitivity is 53.89 pm/°C. In tension experiment, the tension range is 0—1 400 με. The experimental results show that there is no wavelength shift in the interference spectrum. The sensor is immune to tension cross-sensitivity compared with other sensors. It can be used for temperature testing in aerospace, chemistry and pharmacy.     

光子晶体光纤熔接损耗研究

基于有限元法分析了光子晶体光纤模场半径,为了提高计算速度,提出了一种工作波长为1．55μm时,光子晶体光纤模场半径的快速估算方法,进而实现光子晶体光纤熔接损耗的快速估算。分析表明,本文提出的方法能够准确快速的实现光子晶体光纤熔接损耗的估算。     

240Mbit/s直线运动型无线光通信系统研究

详细分析了直线轨道上运动通信的特点,设计和研制了一种具有双向收发功能的直线运动型无线光通信系统。该系统主要包括1 550 nm半导体激光器、高灵敏度PIN光探测器、球面单透镜式光发射天线和实心光锥耦合式光接收天线等关键部件。130 m运动工作距离的系统性能测试结果表明,在3.5 m/s最高运动速度、240Mbit/s通信传输速率下,运动中的数据丢帧率为零,以太网和视频指标均满足实际应用要求,系统适用于存在直线运动轨道的无线光通信场合。     

毛细铜管封装的内嵌式镀金光纤布拉格光栅温度和应力传感器

为了实现复杂、恶劣环境下工程机械表面无损的应力监测方式,实现对大型工程机械的实时动态监测,提出了基于磁控溅射技术的光纤布拉格光栅(FBG)应力传感器封装方法。并对完全嵌套(整个栅区嵌套毛细铜管)和两端嵌套(栅区两端嵌套毛细铜管)两种封装方法开展了研究。从理论分析和有限元仿真的角度比较了传感器的增敏效果,前后结果一致。制备了传感器实物并进行了温度、应力和对比实验。仿真实验结果表明,该模型下FBG传感器能提高约7.5%的灵敏度。温度实验表明第二种封装结构的温度反馈相关系数R2达到了0.99948,在30℃～80℃范围内呈现良好的线性度;应力实验的相关系数R2也达到0.99924,灵敏度为6.14 pm/MPa,在该实验搭建的解调系统下精度达到0.05 MPa,可以快速、精确地解调应力。对比实验表明,光栅解调仪组成的监测系统比应变片组成的监测系统具有更高的精度,最大偏差值减小了59.8%。嵌套毛细铜管的金属化方式结合有机胶固定的封装结构简单、灵敏度和精度高,可以满足大型工程机械表面无损实时健康监测的需求。