光器件用选择截止特种单模光纤的开发

对器件用特种单模光纤的弯曲损耗进行了理论分析,并采用Matlab对弯曲损耗进行了仿真数值分析,研究了单模光纤宏弯损耗和微弯损耗随光纤波导结构及波长的变化规律,并优化了光纤波导结构,开发出抗弯性能优良的单模光纤,同时具有较低的熔接损耗。     

Slot结构聚合物波导微环光学生物传感器研究

Slot结构在提高集成波导光学传感器灵敏度和降低探测极限值方面具有极大的优势。对基于Slot结构的聚合物PSQ-Ls波导微环光学生物传感器进行了研究。分析了850 nm波段Slot波导的单波导高度、狭缝宽度及单波导宽度对传感器灵敏度的影响,在满足单模传输的条件下,得到了优化的微环传感器横截面尺寸参数。对Slot结构波导微环的弯曲损耗、自由光谱范围等进行了仿真分析,得到微环传感器的消光比、品质因子等随结构参数的变化,确定了优化的微环弯曲半径、耦合效率。与正脊形结构波导微环传感器相比,Slot结构波导微环传感器的灵敏度是前者的两倍,探测极限值是其一半。     

适用于硅微谐振器件测量的光纤位移传感器研究

对一种适用于硅微机械谐振器件测量的光纤位移传感器进行了研究,该光纤位移传感器探头采用了单根光纤探测形式和光纤“X”耦合器结构,在微弱光电传感信号处理上采用了“锁相放大器”提取方案,可以实现对静态位移和振动位移两种场合进行测量.对该传感器的实测结果表明:该传感器测量范围为0～100 μm,测量灵敏度3.95 mV/μm,精度等级优于1%,重复性优于0.5%.为作为应用实例,运用该传感系统对一种微悬臂梁硅微谐振器件进行了测量,成功提取了硅微谐振器件的微弱谐振信号,证实了该传感器可以实现对硅微谐振器件的非接触和无损测量,并具有非接触、易调试、高灵敏度等优点.     

光激光拾自谐振传感器的光学特性及优化设计

建立了光激、光拾自谐振多晶硅微机械传感器的多层膜系模型,利用该模型对传感器的光学特性进行了理论分析,并对传感器谐振微梁厚度和空腔高度进行了优化.     

用光学信息理论分析微弯光纤传感器的性能

通过把光学信息理论应用于微弯光纤传感器,用信息量评估测量性能,提出了一种优化系统性能和参数设计的光学信息理论。通过理论推导、直观评价和实验设计,证明了这一思想的正确性和可行性。     

石英音叉温度频率特性的温度传感器（英）

提出了一种基于石英晶体温度频率特性的石英音叉微谐振式温度传感器。通过理论分析的方法对传感器进行设计,并采用有限元仿真对传感器的结构参数进行优化。采用光刻和蚀刻微加工技术制造石英音叉谐振器,对石英音叉温度传感器样机的频率温度特性进行实验研究。实验结果表明:石英音叉温度传感器的标准谐振频率为36.545 kHz,灵敏度为-1.9 Hz/℃,在-20到100 ℃的温度范围内,其非线性误差小于0.18%,迟滞为0.02%,与理论研究相吻合。该传感器具有高精度、高灵敏度、低功耗和低成本的特点,为高性能温度测量提供较好的解决方案。     

微弯光纤传感器的光线寻迹法分析

采用光线寻迹法分析微弯光纤传感器，指出其微弯临界周期即为光线以最大入射角在光纤内传播的空间重复距离，结论与耦合模理论分析及实验结果一致。     

石英音叉温度频率特性的温度传感器（英文）

提出了一种基于石英晶体温度频率特性的石英音叉微谐振式温度传感器。通过理论分析的方法对传感器进行设计,并采用有限元仿真对传感器的结构参数进行优化。采用光刻和蚀刻微加工技术制造石英音叉谐振器,对石英音叉温度传感器样机的频率温度特性进行实验研究。实验结果表明:石英音叉温度传感器的标准谐振频率为36.545kHz,灵敏度为-1.9Hz/℃,在-20到100℃的温度范围内,其非线性误差小于0.18%,迟滞为0.02%,与理论研究相吻合。该传感器具有高精度、高灵敏度、低功耗和低成本的特点,为高性能温度测量提供较好的解决方案。     

反馈式跑道型光学微环的传感灵敏度研究

提出了一种由U型反馈波导、跑道谐振腔和敏感环组成的反馈式跑道型光学微环传感器.采用耦合模理论推导了该传感器的归一化输出光强公式,数值分析了传输损耗因子、自耦合因子和敏感环尺寸对归一化输出光强的影响.分析表明:敏感环的损耗因子对归一化输出光强的调制作用明显,只要损耗因子发生微小变化,输出光强即发生较大变化;敏感环工作在弱耦合状态时传感灵敏度较高;敏感环的尺寸对传感灵敏度影响较大,适当地调整敏感环的大小可得到陡峭的输出光强谱线.对结构参数进行优化后不仅可以输出尖锐陡峭的非对称法诺谐振光强谱线,而且具有较高的法诺谐振光谱斜率,能更好地增强传感灵敏度.在信噪比为30dB的测量系统中,优化的反馈式跑道型光学微环传感器的探测极限达4.48×10-8单位折射率.     

差分谐振式压力微传感器灵敏度匹配特性（英）

谐振式压力微传感器因其高精度、高稳定性及准数字输出等特性而广泛应用于气压监测、航空航天等领域。相较于其他结构,差分谐振式具有灵敏度高、线性度好及温度漂移小等优势。然而,要获得差分谐振式压力微传感器的最优性能,仍需解决差分谐振梁灵敏度不匹配的问题。在仿真与实验的基础上,对差分谐振式压力微传感器的灵敏度匹配特性进行了相关研究。根据研究结果,对传感器的结构参数进行了优化设计。两谐振梁的设计灵敏度为46 Hz/kP,实验结果显示中心梁的实际灵敏度为45 Hz/kPa,边梁的实际灵敏度为-44 Hz/kPa,差分输出的线性度高达0.999 999 9。     

An integrated Mach–Zehnder interferometric biosensor with a silicon oxynitride waveguide by plasma-enhanced chemical vapor deposition

We report the design and fabrication of an integrated Mach–Zehnder interferometric (MZI) biochip based on silicon oxynitride layers deposited with a plasma-enhanced chemical vapor deposition (PECVD) process. A rib waveguide for an integrated MZI sensor has been designed to have a high surface sensitivity and a single-mode behavior by using an effective index method. The integrated MZI chip operating at 637 nm is fabricated via conventional photolithography and reactive ion etching. As a biosensor application, the real-time and label-free detection of the covalent immobilization and hybridization of DNA strands is performed and verified with this device.     

Sensitivity enhancement in TE mode nonlinear planar optical waveguide sensor with metamaterial layer

The dispersion equation of the TE mode nonlinear planar optical waveguide with metamaterial layer was derived, and the sensitivity of the waveguide sensor was analyzed. The influences of structural parameters on the sensitivity of the waveguide sensor were investigated. We verify that the waveguide sensor with metamaterial layer can dramatically enhance the sensitivity compared with other waveguide sensors.     

Single S-tapered fiber Mach-Zehnder interferometers

A fiber Mach-Zehnder interferometer (MZI) sensor, novel to our knowledge, based on a single "S"-like fiber taper has been fabricated via applying nonaxial pull in fiber tapering by a fusion splicer. The typical feature size of the structure has a length of 660 μm and the axial offset of 96 μm. This S fiber taper MZI has a refractive index (RI) sensitivity of 1590 nm/refractive index unit in the RI range of 1.409-1.425 and a strain sensitivity of about -60 pm/microstrain, which is 30 times higher than that of the normal two-taper-based MZI sensors.     

Theoretical modeling of a nonlinear asymmetric metal-clad planar waveguide based sensors

The present paper deals with the theoretical modeling of a nonlinear asymmetrical metal-clad planar waveguide for sensor application to achieve high sensitivity. We take the appropriate field distributions for the proposed structure and impose the boundary conditions to derive the mode equation and other necessary formulae for the proposed sensor. The effect of nonlinearity on the sensitivity of the waveguide is studied. Also, we have compared our computed results with the results given for a similar sensor having five layers structure. It is observed that the sensitivity of the sensor is improved by introducing a nonlinear material in the cover medium.     

Theory of absorption integrated optical sensor of gaseous materials

The eigen and noneigen (leaky) modes of a three-layer planar integrated optical waveguide are described. The dispersion relation of a three-layer planar waveguide and other dependences are derived, and the cutoff conditions are analyzed. The diagram of propagation constants of the guided and radiation modes of an irregular asymmetric three-layer waveguide and the dependence of the electric field amplitudes of radiation modes of substrate on vertical coordinate in a tantalum integrated optical waveguide are presented. The operating principles of an absorption integrated optical waveguide sensor are investigated. The dependences of sensitivity of an integrated optical waveguide sensor on the sensory cell length, the coupling efficiency of the laser radiation into the waveguide, the absorption cross-section of the studied material, and the level of additive statistical noise are investigated. Some of the prospective areas of application of integrated-optical waveguide sensors are outlined.     

Fabrication and study of a metal-clad planar waveguide based biosensor

A metal-clad planar optical waveguide biosensor having five layer structure has been fabricated to study the detection of Pseudomonas and Pseudomonas-like bacteria. This waveguide is designed to increase the overlap of the evanescent field extension from the sensor face with the micro-scale biological objects in the bulk solution, to place most of the entire volume of the bacteria within the evanescent field. The results presented here leads to a significant optimization of the important design parameters to sense micro-scale biological objects. We have compared our computed results with the results obtained by similar non-metallic clad biosensor. The effect of affinity-layer refractive index on the sensitivity of these planar waveguides is also studied. We have shown this for some special cases by obtaining reflection dips at the particular angle of incidence. Our observations show that the metal-clad planar optical waveguide biosensor having higher affinity refractive index will give better sensitivity than other similar non-metallic clad biosensor. The validation of metal-clad planar optical waveguide sensor for the detection of Pseudomonas aeruginosa bacterium is also made.     

Liquid refractive index sensor based on slow light in slotted photonic crystal waveguide

A high sensitive and compact refractive index sensor based on slotted photonic crystal waveguide (S-PhCW) is demonstrated. This design is worked on a Mach–Zehnder interferometer (MZI) configuration with S-PhCW as the measuring arm, which can be used to detect any changes in refractive index that correspond to different concentration of the measuring liquid. Combining the slow light enhancement in photonic crystal waveguide (PhCW) with the advantage of excellent optical confinement in slot waveguide, the sensitivity of this simple scheme can reach to 2.3 × 10⁹ nm/RIU with the active region of only 1 mm long.     

Optical modulator based on negative refractive material

Using negative refractive material slow-wave waveguide, a compact and integrated optical modulator is proposed for the first time to our knowledge. The slow group velocities of light, which are readily achievable in negative refractive material waveguide, can dramatically increase the induced phase shifts caused by small changes in the refractive index. Modulation operation with a 40 μm long negative refractive material slow-wave waveguide of a Mach–Zehnder interferometer (MZI) structure was demonstrated by using finite-element method. The size of the novel optical modulator is 100 times shorter than that of the conventional lithium niobate MZI optical modulator.     

Bending sensor based on intermodal interference properties of two-dimensional waveguide array fiber

We propose a highly sensitive bending sensor based on the intermodal interference properties of a strongly coupled two-dimentional waveguide array fiber (WAF). The interference resonance peaks formed by the SMF-WAF-SMF Mach-Zehnder interferometer are intrinsically the result of interference between the LP(01)-like supermode and other higher order supermodes, displaying supernormal sensitivity to bending in a wide curvature range. The bending sensitivity of the intermodal MZI is a quadratic function of curvature, and the resonance wavelength shift is up to 100 nm within a curvature range 0-10 m(-1). The fabrication reveals briefness, and temperature response shows little impact on the bend sensing precision. The high bending sensitivity and wide sensing range can make this device a candidate for bending discrimination and measurement in widespread areas.     

基于少模-无芯-少模光纤结构的高灵敏度折射率传感器

光纤折射率传感器广泛应用于各种复杂环境的监测。设计了一种基于少模光纤（fewmode fiber,FMF）–无芯光纤（coreless fiber,CLF）–FMF结构的高灵敏度折射率传感器。该传感器由2小段FMF之间熔接1段减薄的CLF组成马赫-增德尔干涉仪（Mach–Zehnder interference,MZI）,测量外界折射率,利用光纤布拉格光栅（fiber Bragg grating,FBG）进行温度补偿。MZI干涉光谱中的谐振波谷同时受折射率和温度影响,FBG只受温度的影响。利用MZI和FBG的折射率和温度灵敏度系数构建灵敏度矩阵,实现折射率和温度的同步测量。实验结果表明,MZI折射率灵敏度为345.66 nm/RIU,温度灵敏度为0.013 4 nm/℃;FBG的温度灵敏度为0.010 4 nm/℃。