基于多模态双偏置光纤的折射率传感机理研究

提出了一种基于双偏置结构光纤马赫-曾德干涉仪(Mach-Zehnder interferometer, MZI)的超高灵敏度折射率传感器,理论分析了偏置型MZI的干涉机理。通过光束传播法(beam propagation method, BPM)模拟分析了多模态偏置光纤的折射率传感特性、以及在不同偏置长度和折射率范围内折射率灵敏度的变化,对比了单偏置与双偏置的传感特性。仿真结果表明,在折射率为1.333 0—1.334 0的范围内,单偏置MZI的折射率灵敏度为-5 557 nm/RIU,而双偏置MZI的折射率灵敏度为-14 071 nm/RIU,该结果为实现高灵敏度液体折射率测量提供了重要理论依据。该传感器结构紧凑,整体长度只有1 200μm,在液体折射率测量领域具有重要的应用价值。     

玻璃波导有效折射率的原位测量（特邀）

飞秒激光直写玻璃波导是快速制备三维集成光子芯片的一种重要手段,波导有效折射率的准确测量对于设计光子器件意义重大。设计并制备了一种断臂马赫-曾德尔干涉仪（MZI）结构对玻璃波导有效折射率进行原位精密测量。激光在断线区域和波导内的有效折射率不同,在传输相同长度下产生一定的相位差,最终导致不同的干涉结果。对断臂MZI结构的相位干涉结果进行处理,得到激光直写玻璃波导的有效折射率为1.504+7.7×10?4。利用RSOFT软件光束传播算法对器件进行模拟仿真,仿真结果与实验吻合良好。该精确测量玻璃波导有效折射率的方法对于提升光子芯片设计与制造能力具有重要意义。     

一种基于MZI的聚合物光波导加速度计

提出了一种基于马赫增德尔干涉仪（MZI）的聚合物光学波导加速度计。理论推导了MZI结构的传输函数,仿真分析了悬臂梁结构参数与器件灵敏度的关系,制备和测试了基于聚合物材料和柔性衬底的加速度传感芯片。制备得到了4 μm×4 μm单模传输芯层波导的传感芯片。搭建了集成光学加速度测试系统,采用比较校准法对探测器输出电压信号进行标定,实现了传感芯片因施加加速度后输出光强变化的测试,完成了加速度测量。该加速度传感芯片分辨率为10-2 g,动态范围为±2 g。     

SiO2基Mach-Zehnder型传感芯片的制备与敏感性研究

设计并制作了一种基于SiO2/Si材料的Mach-Zehnder干涉仪(MZI)型集成光波导传感芯片.采用不同浓度的NaCl溶液对传感芯片的敏感特性进行了测试分析,研究结果表明,该传感芯片对特定浓度NaCl溶液的响应和恢复时间分别为1.0 s和0.6 s,可测最小折射率变化为2×10-4RIU(单位折射率变化),在Na...     

级联FPI-MZI复合干涉光纤传感器双参数特性研究

为了实现工业生产过程中温度和溶液质量分数的同时测量和传感检测, 提出了一种由法布里-珀罗干涉仪(FPI)和马赫-曾德尔干涉仪(MZI)级联干涉结构构成的双参数传感器。该传感器由融合在一起的单模光纤(SMF)和空芯光纤(HCF)组成。采用同时测量FPI反射光谱和MZI透射光谱的特征波长位移的方法, 获得了FPI和MZI对温度和折射率的灵敏度差, 建立了传感器温度-质量分数灵敏度矩阵, 实现了传感器双参数的测量。结果表明, 在40℃~150℃的温度范围内, FPI的温度敏感度为10pm/℃, 而MZI的对温度不敏感; 在质量分数0.05~0.40的范围内, FPI对折射率不敏感, 而MZI质量分数灵敏度是232.3nm/RIU; 该传感器可以实现温度与溶液质量分数的同时测量。该研究为石油、化工、电力、钢铁、机械等加工行业中双参数的动态测量提供了参考。     

微纳光纤马赫-泽德干涉仪

马赫-泽德干涉仪(MZI)是一种重要的光学和光子学器件,广泛应用于干涉计量、光通信等领域.基于干涉仪对波导及其周围介质折射率的相位敏感特性,MZI被广泛用作传感器和光调制器.最近,我们通过光学显微镜下的微纳操作,在低折射率衬底上分别用氧化硅和碲酸盐玻璃微纳光纤成功研制了微纳光纤MZI[1].     

三阶聚合物波导布拉格光栅的设计与制备

利用紫外固化聚合物材料ZPU46和ZPU44分别作为 芯层和包层材料,设计并制备了中心波长在 1550nm附近的三阶聚合物波导布拉格光栅(WBG )滤波器。采用接触式光刻和反应离子刻蚀(RIE)等传统微加工工艺, 在高为4μm的单模矩形波导表面制备周期为1.6μm、高为 680nm的皱褶型光栅结构。实验测得截面 尺寸为4μm×4.2μm和5μm×4.2μm) 的三阶聚合物WBG的谐振波长分 别为1549550.5nm,边模抑制比分别为 19dB,3dB带宽分别为0.4nm和0.6nm,插入损耗为－7d B,与理论设计结果符合较好。     

聚合物光波导放大器材料的光学参数及器件制备

使用甲基丙烯酸甲酯(MMA)和甲基丙稀酸环氧丙酯(GMA)共聚,并加入双酚A环氧脂(bis-phenol-A-epoxy)来调节折射率,制备了无源波导材料.使用铒的配合物ErYb(DBM) 2M和MMA、GMA共聚,再加入双酚A环氧树脂调节折射率,制备了用于光波导放大器有源波导料使用椭偏仪对无源和有源的聚合物薄膜的折射率、消光系数和厚度进行了测量.无源的聚物折射率随着环氧树脂含量的增加而线性增加.铒的配合物共聚进聚合物基质中使1.55 μm波段折射率和消光系数增加.无源和有源波导材料的折射率可调节范围在大约在1.48～1.53厚度可调节范围大约在1～6 μm.用有源聚合物材料作芯层、无源聚合物材料作包层,制备了1.55 μm单模有源波导,并得到了圆形的近场光斑.     

基于对称平板波导型SPR液体折射率传感特性

表面等离子体共振(SPR)技术在外界环境折射率测量上有着广泛应用。设计了一种对称平板波导结构,利用时域有限差分法对波导结构中SPR效应与外界环境折射率的关系进行数值模拟,对金属材料选择以及传感区域长度进行了优化,并研究了不同阶次的模式对传感器灵敏度的影响。仿真结果表明:当外界环境折射率为1.38时,相较于基模条件下4100 nm/RIU的灵敏度,三阶模传感器的灵敏度提高到6209 nm/RIU,最大灵敏度提高了51%;当外界环境折射率为1.34~1.38时,传感器平均灵敏度从2900 nm/RIU提高到4025 nm/RIU。     

直接熔融塌陷光子晶体光纤马赫-曾德尔干涉仪的折射率传感特性

研制了一种直接熔融塌陷锥形光子晶体光纤(PCF)马赫-曾德尔干涉仪(MZI)传感器,它是通过电弧放电的方法使光子晶体光纤空气孔受热塌陷,从而直接在光子晶体光纤上形成一个锥区制作而成的,可通过控制电弧参数以及放电次数来灵活控制锥区结构。研究了不同锥区长度下的输出光谱及其传输光谱随外界(RI)折射率的变化关系。实验结果表明,随着锥区长度的增加,在整个波长范围内MZI输出光谱的自由光谱区减小,且自由光谱区在1554.34nm波长附近由33.38nm减小到7.86nm。在1.3414~1.3862折射率变化范围内,该传感器的折射率测量灵敏度可达276.38nm/RIU(RIU为折射率单位)。     

基于双锥形光子晶体光纤的折射率传感器

设计了一种基于光子晶体光纤的双锥形马赫-曾德尔干涉仪,并对其折射率传感特性进行了研究。在FDTD Solutions光学仿真平台中建立了干涉仪结构模型,研究了该结构的透射光谱对环境折射率的响应。仿真结果表明,透射光谱随环境折射率的增加发生红移,灵敏度为95.906nm/RIU。利用熔接与拉锥工艺制备了干涉仪样品,搭建了实验系统,在不同浓度甘油溶液中对其透射谱进行了检测,实验结果表明,折射率在1.3222~1.3538范围内,透射谱偏移灵敏度为121.95nm/RIU。该传感器具有体积小、重量轻、易于制备、灵敏度高等优点,适用于生化和物理传感领域。     

基于纺锤型空气腔的光纤马赫-曾德尔折射率传感器

设计了一种基于光纤纺锤型空气腔的三明治结构全光纤马赫-曾德尔折射率传感器。纺锤型空气腔是通过普通单模光纤和光子晶体光纤熔接后再拉锥形成的。锥区的纺锤型空气腔和包层分别作为参考臂和传感臂,从而形成马赫-曾德尔干涉。基于FDTD Solutions和COMSOL仿真软件分别对传感器的干涉条纹及锥区电场分布进行了仿真,得到了折射率传感器干涉条纹波谷波长和有效折射率与环境折射率的关系。当环境折射率为1.36~1.37和1.37~1.38时,灵敏度分别为1 377.6和1 436nm/RIU。此传感器具有极短的干涉臂,能够降低损耗,且具有较高的折射率灵敏度。     

Intermodal interference based refractive index sensor employing elliptical core photonic crystal fiber

A refractive index (RI) sensor based on elliptical core photonic crystal fiber (EC-PCF) has been proposed. The asymmetric elliptical core introduces the polarization-dependent characteristics of the fiber core modes. The performances of intermodal interference between the intrinsic polarization fiber core modes are investigated by contrast in two interferometers based on the Mach-Zehnder (M-Z) and Sagnac interference model. In addition, the RI sensing characteristics of the two interferometers are studied by successively filling the three layers air holes closest to the elliptical core in the cladding. The results show that the M-Z interference between LP01 and LP11 mode in the same polarized direction is featured with the incremental RI sensing sensitivity as the decreasing interference length, and the infilled scope around the elliptical core has a weak correlation with the RI sensing sensitivity. Due to the high birefringence of LP11 mode, the Sagnac interferometer has better RI sensing performance, the maximum RI sensing sensitivity of 12 000 nm/RIU is achieved under the innermost one layer air holes infilled with RI matching liquid of RI=1.39 at the pre-setting EC-PCF length of 12 cm, which is two orders of magnitude higher than the M-Z interferometer with the same fiber length. The series of theoretical optimized analysis would provide guidance for the applications in the field of biochemical sensing.     

Single-Mode Fiber Refractive Index Sensor Based on Core-Offset Attenuators

Mach-Zehnder and Michelson interferometers using core-offset attenuators were demonstrated. As the relative offset direction of the two attenuators in the Mach-Zehnder interferometer can significantly affect the extinction ratio of the interference pattern, single core-offset attenuator-based sensors appear more robust and repeatable. A novel fiber Michelson interferometer refractive index (RI) sensor was subsequently realized by a single core-offset attenuator and a layer of ~ 500-nm gold coating. The device had a minimum insertion loss of 0.01 dB and maximum extinction ratio over 9 dB. The sensitivity (0.333 nm) of the new sensor to its surrounding RI change (0.01) was found to be comparable to that (0.252 nm) of an identical long period gratings pair Mach-Zehnder interferometric sensor, and its ease of fabrication makes it a low-cost alternative to existing sensing applications.     

Optical waveguide electric field sensor with controllable operating point using asymmetric Mach-Zehnder structure

For an integrated electro-optical sensor, the operating point has a significant effect on the performance of the sensor. In this paper, an optical waveguide electric field sensor with controllable operating point is designed using LiNbO3 materials, which has an asymmetric Mach-Zehnder interferometer (MZI) structure. Theoretical results show that the optimal operating point can be obtained and controlled by tuning the output wavelength of the tunable laser used in the sensing system. The simulation results show that the sensitivity about 83 dB·μV/m can be obtained, and the linear dynamic range as large as 60 dB can be achieved. And the fabrication tolerance of the center-to-center distance for the 3 dB coupler used in the asymmetric MZI is ~0.5 μm, while the power splitting ratio of the Y branch is with more tolerance.     

Elastooptical properties of SiON layers in an integrated opticalinterferometer used as a pressure sensor

This work presents the design and realization of an integrated optical pressure sensor, which is based on the photoelastic birefringence of thin SiO₂ and SiON layers. The advantage of this well known and controlled silicon technology is that optical and electronic circuits as well as micromechanics can be integrated on the same substrate. The sensor is made of a monomode striploaded Mach-Zehnder interferometer, which is placed on a silicon membrane as the pressure sensitive region. The detector is integrated into the silicon substrate, because a wavelength below 1 μm(He-Ne laser source: 632.8 nm) is used. Experimental and theoretical results of the sensor response are presented that demonstrate that efficient sensors can be designed and fabricated and that the TM-polarization gives the higher sensitivity     

High-Temperature Sensing Using Miniaturized Fiber In-Line Mach–Zehnder Interferometer

A miniaturized single fiber in-line Mach-Zehnder interferometer is proposed for high-temperature sensing. The interferometer has a microcavity in one of its arms, formed by removing part of the fiber core and cladding, while the other arm remains in the fiber core. Because the fiber core exhibits a temperature coefficient of refractive index which is different from that of air, the interferometer is sensitive to temperature variation. The microcavity structured interferometer also has excellent sustainability to high temperatures up to 1100°C . The system is compact, reliable and can detect the temperature at precise location.     

Design and analysis of silicon antiresonant reflecting opticalwaveguides for evanescent field sensor

Silicon based antiresonant reflecting optical waveguides (ARROW's) have been designed in order to obtain a high sensitive optical transducer for sensing applications. The designed sensor has an integrated Mach-Zehnder interferometer configuration. The optical waveguides that form its structure have to verify two conditions: monomode behavior and high surface sensitivity. In this paper, we present a theoretical modeling of the propagation characteristics and surface sensitivity of the ARROW structure