柔性-微环光波导耦合结构的集成光学加速度传感器

给出了一种利用柔性-微环光波导耦合结构的集成光学加速度传感器.通过聚合物材料设计的柔性光波导,在外力作用下产生形变.该形变改变了柔性光波导与微环光波导的层间距,从而改变波导耦合器的耦合比,使得微环光波导谐振腔输出谱特性发生相应改变.继而有效地实现了加速度的传感.本文给出了这种新型的设计,推导了其检测原理并同时分析了其灵敏度的影响因素.     

微光学陀螺波导谐振腔的优化设计

提出一种应用于微型光学陀螺的谐振腔的优化设计方案,优化设计方案同时兼顾微型光学陀螺精度要求与其系统微型化设计。光波导材料为传输损耗为0.01dB/cm的硅基二氧化硅材料,有效的降低了谐振腔内部的损耗,使得谐振腔内损耗仅为0.5dB,利于谐振腔的高精度;光波导结构采用准单模矩形结构,利用腔中的弯曲波导对一阶模的有效滤除实现了光的基模传输,利于谐振腔的小型化;此外分析了波导的传输损耗、波导耦合器分光比对谐振腔性能及陀螺极限灵敏度的影响,得出波导耦合器分光比的优化参数,并仿真得到谐振腔的谐振清晰度达到70以上。假定在激光光源线宽为30kHz,探测器响应度0.95A/W,积分时间为10s的条件下,仿真得到系统的极限灵敏度为1.6°/h左右。最后实验验证了此优化设计方法是有效可行的。     

用于光电集成收发模块的SOI波导耦合器设计

基于光纤陀螺的小型化和工程化设计要求,提出模块化设计概念。设计了一种Y型SOI波导耦合器,用于光纤陀螺光收发模块。此结构具有形式简单、谱宽、加工工艺成熟和易于实现光电集成等技术优势。理论上分析了波导结构参数对其特征参数(分光比、损耗)的影响,优化参数设计,通过模场匹配理论减小器件损耗。最后,对波导耦合器加工工艺进行了讨论,采用电子束光刻技术加工出波导掩膜版,并对加工工艺参数进行了优化。实验结果表明:所设计的分光比50%:50%波导耦合器,当波导长为25mm时,输入输出波导的间距可以达到300μm,且理论弯曲损耗可忽略不计,可以有效的抑制光源与耦合器的串音干扰。通过优化工艺参数,设计的SOI波导耦合器可以满足设计要求。     

光桥平衡补偿型光纤双向应变位移传感器

在光桥平衡补偿型光纤双向应变位移传感器中,光源发出的光被3dB耦合器分束到拉敏光纤和参考光纤或压敏光纤和参考光纤中,而这些调制光和参考光由两光探测器分别进行测量。通过自相关损耗,可有效消除光纤应变位移传感器中光源功率波动、光纤传输损耗的变化以及光探测器灵敏度的漂移所引起的误差。微位移架上的位移实验表明:误差为0.01mm。     

高灵敏复合光波导传感器及其研究进展

高灵敏复合光波导是在K 交换玻璃光波导上面涂(溅射法或旋转涂膜法)两端带斜坡的高折射率薄膜而研制出的一种元件.该元件表面灵敏度比K 交换玻璃光波导或分光光度法的灵敏度高出了2～3个数量级.利用复合光波导研制的氨气传感器和免疫传感器的灵敏度达到了世界领先水平.光波导传感器具有体积小,响应快,灵敏度高等特点.该文较全面介绍了利用高折射率薄膜设计和研制高灵敏复合光波导及其在化学生物传感器中的应用,并对未来光波导传感器的研究作了展望.     

MZI型MOEMS压力传感器的研究

集成光学压力传感器利用幅度、相位、折射率分布、光程和光波极化方式的改变来感应外部压力。设计了马赫-曾德尔干涉仪（MZI）型微型光机电系统（MOEMS）压力传感器,探讨了工作原理,分析了弹性薄膜尺寸对应力的影响和波导中TE、TM模式的光对波导折射率的影响。通过设计弹性薄膜的尺寸和选用特定波长的单模激光,得到传感器的工作特性。     

基于奇偶模分析法的微波带状线定向耦合器设计

基于奇偶模分析法分析了从一节至多节的耦合器设计公式,并以此设计了1 ～2 GHz的多节交错级联3 dB带状线定向耦合器.采用HFSS对所建立的耦合器模型进行了仿真.仿真结果表明,该带状线耦合器在通带内的传输损耗、反射系数、输出隔离度均在-20 dB以下,直通耦合平坦度在±0.4 dB以内,输入输出驻波比小于1.2.该方法为同类宽带强耦合度的耦合器的研究提供了一定的参考价值.     

纳米光波导表面粗糙度与散射损耗的分析与测试

针对目前纳米光波导传输中散射损耗严重的问题,详细分析了表面粗糙度与波导宽度对散射损耗的影响,给出了清晰的对应关系图。设计并采用MEMS工艺制备出纳米光波导结构,在此基础上对波导结构进行了表面粗糙度的测试,进一步提出采用高温热处理方法使波导表面粗糙度降低了3 nm左右。实验发现:高温热处理后的光波导结构其散射损耗降低到3.343 dB/cm。     

一种基于位相调制的光纤电压传感器

一种基于位相调制原理的光纤电压传感器,充分利用3×3光纤定向耦合器的光学特性,使得光路结构更加简单、可靠.光路设计中舍弃了温度效应显著的波片,并利用3×3光纤定向耦合器实现了光的正交干涉.在信号处理中利用软件解调的方式大大简化了硬件电路设计,并消除了由此引入一系列不稳定因素提高了测量结果的可靠性.试验结果表明,该系统有较好的温度稳定性,其精度优于0.91%,可以推广应用于电力系统.     

硅微机械加工光波导压力传感器的设计

随着波导材料的研究和进展 ,采用新的波导材料设计出了一种波导式压力传感器 ,就光波导压力传感器的原理和特性作了一个简要阐述 ,对它的工艺流程作了详细的描述     

Fiber optic strain twin-sensor-array for smart structural health monitoring

A multiplexed white light interferometric fiber optic twin-sensor-array was designed to monitor the structural health of large buildings. In this sensing system, based on a Michelson interferometer, an optical path matching technique is used to demodulate each twin-sensor. Each twin-sensor-array consists of a 2×N sensing element linked by a 3 dB coupler. When one of the twin-sensor is used to measure strain, variations caused by temperature can be compensated for by referencing the other twin-sensor. The multiplexing capacity of the sensing scheme has been analyzed and experimental results with a 2×3 twin-sensor-array are given.     

Technological aspects on the fabrication of silicon-based optical accelerometer with ARROW structures

The fabrication and characterization of an optical accelerometer based on silicon technology and using BESOI wafers is presented. Instead of the standard total internal reflection (TIR) waveguides, AntiResonant Reflecting Optical Waveguides (ARROW) have been used. On the basis of a quad beam accelerometer design, a sensing waveguide has been placed on the seismic mass. Its misalignment with the waveguides located at the frame allows measuring the acceleration. The mechanical structure has been designed so as to have a span of 2 μm, that should provide with a sensitivity of 4.6 dB/g. Reference waveguides measured by end-fire coupling have low radiation and insertion losses (0.3 and 2.5 dB, respectively). High insertion losses are observed due to imperfections in polishing when V-grooves with glass anodic bonding are used. This fact causes the reduction of its sensibility to 2.3 dB/g.     

Accurate and efficient design technique for wideband substrate integrated waveguide directional couplers

In this article, we present an efficient technique for the accurate design of wideband substrate integrate waveguide directional couplers. By tapering the coupling section, the bandwidth of substrate integrated waveguide (SIW) directional couplers can be enlarged. Two design aspects are involved in this approach. First, the even‐mode propagation constant in the tapered coupling section is accurately extracted with the help of a numerical thru‐reflect‐line calibration technique. Then, it is fitted into the model of a uniform dielectric‐filled rectangular waveguide and thereafter extrapolated to the operation range of the odd mode. Second, equivalent circuit models of the waveguide bifurcation effects are also presented together with parametric values. Based on the results of extraction, a 90° 3‐dB directional coupler is developed to validate the proposed design approach. To achieve the reverse phasing at two output ports, the prototyped 90° 3‐dB directional coupler is subsequently integrated with a novel broadband fixed phase shifter developed with the SIW technology, of which a systematic synthesis procedure has been proposed in this article. Measured performance of both 90° and 180° 3‐dB couplers confirms the accuracy of our proposed design approach. This kind of wide‐band directional coupler can find applications in wideband power dividing/combining circuits within a single‐layer platform. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2012.     

用于波分复用的1×4多模干涉耦合器

根据多模干涉(MMI)技术和波分复用原理,设计并研制出应用于波分复用系统的1×4钛扩散铌酸锂(Ti:LiNbO3/LiNbO3)多模干涉耦合器.对MMI耦合器进行了理论研究和设计计算,完成了结构参数的优化设计、特性参数(损耗,分光比)的计算和实验验证,并与常规的M-Z型耦合器进行了对比.设计出的1×4MMI耦合器的长度为6 mm,损耗为1.4 dB,而使用三个M-Z型耦合器构成1×4耦合器,总长度为60 mm,总损耗为1.5 dB;因此,采用MMI耦合器,具有结构紧凑、损耗低、工艺简单、容差性好等一系列独特的优点.     

Integrated optical micro structures for signal processing in the position metrology

The miniaturisation of functional components and a high integration depth of sensor systems are the fundamental demands of the micro system technology. Within the, ‘Sonderforschungsbereich 516,’ the development of a position sensor for a micro linear motor is also directed towards these goals; and so a sensor with a size smaller than 10 mm and a measurement accuracy of better than 100 nm is desirable. Additionally, the electromagnetic sensitivity should be minimised. An optical interferometric measurement principle meets these requirements. Light from both of the first diffraction orders from a grating on the motor armature is coupled into a glass-chip waveguide coupler. The interference of the signals results in a beat frequency signal when the grating is shifted. It can be detected as an intensity modulation at the three outputs. The velocity as well as the movement direction of the armature can be derived from the signal phases. The investigations were focused on the coupler design and its numerical field simulations as well as manufacturing and qualification of the coupler itself. Its geometry essentially affects the total sensor length. Refractive index modification by a femtosecond pulse laser was chosen for the creation of the waveguide coupler. This process does not restrict the waveguide geometry to the surface of the glass-chip, and enables arbitrarily positioning of waveguides in the substrate volume. Thus, it also enables non-planar cross section formations of three waveguides e.g. in the form of an equilateral triangle.     

Design of X‐band Moreno cross‐guide coupler based on superformula curves

This article deals with the design of Moreno cross‐guide couplers based on supershapes for X‐band applications. Crossed‐waveguide couplers are mainly used due to their compact structures. In these couplers, cross‐aperture structures are usually employed to offer flat coupling and high isolation. In the present article, the possible shapes for apertures and metal inserts that can be derived by the superfomula curves are explored and the effects of variations of superformula parameters are investigated on the performance of Moreno coupler. Finally, the proposed Moreno coupler is validated through fabrication and measurement. The experimental validation shows an excellent agreement with the simulated results. In the frequency range from 8 to 12.5 GHz, the measured coupling value changes from 18.8 to 20.8 dB and the directivity is better than 38 dB and 29 dB from 8 to 11 GHz and 11 to 12.5 GHz, respectively. The results are valuable for the design and evaluation of broadband high directive waveguide couplers.     

Performance of a highly sensitive optical waveguide Mach-Zehnder interferometer immunosensor

We describe a highly sensitive sensor which uses the evanescent field of a reusable planar optical waveguide as the sensing element. The waveguide used is optimized to obtain a steep dependence of the propagation velocity on the refractive-index profile near the surface. The adsorption of a layer of proteins thus results in a phase change, which is measured interferometrically using a Mach-Zehnder interferometer set-up. The stability of the interferometer is such that phase changes ≈ (1 × 10⁻²)2π per hour can be measured. Immunoreactions have been monitored down to concentrations of 5 × 10⁻¹¹ M of a 40 kDa protein.     

垂直纳米光栅耦合器耦合效率分析与测试

介绍了基于Sol纳米光栅耦合器的理论研究及测试方法,系统研究了光栅参数对光栅耦合效率的影响,在占空比为1:1的基础上,对不同光栅槽深作了相应的理论分析,同时,还对不同角度的入射光作了相应的研究,经过仿真在入射角为10°时,对于波长为l 550 nm的入射光其耦合效率最高.除此之外,通过在光栅表面添加增透膜使其耦合效率在...