LiNbO3光波导紫外表面等离子共振传感器模拟计算

高折射率的LiNbO3光波导,构成四层高折射率波导表面等离子共振传感器.采用传输矩阵方法得基模TM模色散表达式,研究了光波导有效折射与样品折射率之间的关系、光波导传输常数和波长的关系,由表面等离子体波共振耦合条件,得到不同样品折射率的表面等离子共振波长.利用菲涅耳的反射率公式,计算了四层结构波导传感器的透射谱,得到表面...     

光波导器件计算机辅助分析系统

介绍了一个光波导器件计算机辅助分析系统,该系统集成了３个实用工具：光波导有效折射率计算工具,光波导模式求解工具和三维复折射率全矢量有限差分束传播法模拟工具,本系统用于线性波导器件,模拟光在波导中的传播过程,从而可以优化设计波导器件,探索新结构器件。     

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.     

薄包层长周期光纤光栅的折射率传感特性

长周期光纤光栅(LPFG)可用于折射率传感,同时利用折射变化可以实现谐振波长的调谐.不同的光纤包层半径和光栅周期对折射率灵敏度有较大影响.利用光波导的耦合模理论分析了LPFG的折射率传感特性,给出LPFG的折射率灵敏度的解析表达式,给出了利用不同包层模时的折射率灵敏度.利用三层介质光纤的纤芯模本征方程计算了薄包层LPFG的折射率灵敏度.结果表明,基于不同包层模的LPFG的谐振波长随折射率的变化有红移,也有兰移;基于低阶模序包层模的LPFG,折射率灵敏度较小,中间模序最大,而高阶模序则较大,薄包层LPFG对折射率具有更大的灵敏度.     

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.     

退火质子交换Y分支波导弯曲损耗分析

退火质子交换铌酸锂光波导是一类重要的光波导.对采用该技术制备的,具有余弦型弯曲的Y分支光波导,利用宽角有限差分光束传播法,就过渡区长度、波导折射率增量、掩模版开口宽度等对波导弯曲损耗的影响进行了研究,并与余弦型弯曲波导进行了比较.结果表明,Y分支波导和余弦型弯曲波导的弯曲损耗,随波导结构参数的变化基本上是相同的,但二者的表现并不完全一致,因而对Y分支波导结构参数的选择,不能完全依赖于余弦弯曲波导结构的优化.数值结果为相应波导器件的设计和制备提供了一定的参考.     

一种FDTD仿真软件提取波导S参数的方法

在计算矩形波导的S参数时 ,一些基于FDTD方法的电磁场数值仿真软件只提供了激励点的S参数。在实际应用中 ,针对波导往往要求计算截面间的S参数 ,这使得不能直接利用该软件给出的结果。该文利用FDTD软件输出的稳态场分布 ,通过计算坡印廷矢量提取波导的S参数。通过比较不同计算时间步、空间步长、负载、吸收边界等对本提取方法的影响 ,验证了基于坡印廷矢量计算波导S参数的方法 ,并对一个实例进行了计算。本方法也可用于圆波导、同轴线等类似结构中S参数的提取     

基于扰动理论的蒸发波导传播模态分析方法

蒸发波导足形成海上微波超视距传播的主要机制,波导模态理论用于研究微波在蒸发波导中的传播特性,但求解过程复杂,计算时间较长不适于实时应用.根据蒸发波导折射率垂直剖面情况,提出了扰动理论和波导模态理论结合的方法,简化了求解过程,提高了计算效率.应用所编制的模态分析程序,仿真计算了蒸发波导高度不同时低阶模态的传播常数,并与算例比较,验证了方法的计算精确性和快速性.同时进一步分析并给出了信号频率与蒸发波导特性参数及场分布之间的关系.     

抗共振反射集成光学传感器的研究进展

抗共振反射光波导(ARROW)具有与传统光波导所不同的传播特性。利用覆盖层的抗共振反射性质,ARROW传播单模、高阶模被泄漏到基体。基于折射率的变化,抗共振反射传感器对物理量、化学量和生物分子间的相互作用有很高的敏感性。介绍了ARROW的结构、传感器的工作原理以及最新研究进展。由于可采用CMOS工艺制作波导,且能与光探测器在一块集成,抗共振反射传感器将具有广阔的应用前景。     

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。     

阵列化锰铜高压传感器的研制

通过传感器的结构设计、敏感材料和封装材料的研制以及采用新的传感器制备工艺,制作了一种新型的薄膜式锰铜传感器。采用熔融石英材料作为绝缘基板。在绝缘基板上沉积锰铜敏感薄膜。并在敏感薄膜的上面沉积SiO2封装层薄膜。根据"后置"式传感器由阻抗匹配原则,计算出铝靶板中的最高压力为51.68GPa,SiO2封装材料中的压力为35.396GPa。     

Properties of M-AFM probe affected by nanostructural metal coatings

In order to develop a new structure microwave probe, the fabrication of the atomic force microscope (AFM) probe on a GaAs wafer was studied and characteristics of the AFM probe with different nanostructural metal coating were evaluated in order to understand the performance of the probe for the topography of materials and the propagation of microwave signals. A waveguide was introduced by the sputtering and the electron beam (EB) evaporation technique on the top and bottom surfaces of the GaAs AFM probe with Au or Al film. The open structure of the waveguide at the tip of the probe was introduced by using focused ion beam fabrication. It was found that the fabricated probes coated with the Au or Al film have nanometer order resolution. Moreover, using the Au-coating probe formed by the EB evaporation technique, microwave emission was detected successfully at the tip of the probe by approaching an Au film sample.     

Soft lithography fabrication of index-matched microfluidic devices for reducing artifacts in fluorescence and quantitative phase imaging

Microfluidic devices are widely used for biomedical applications based on microscopy or other optical detection methods. However, the materials commonly used for microfabrication typically have a high refractive index relative to water, which can create artifacts at device edges and limit applicability to applications requiring high-precision imaging or morphological feature detection. Here we present a soft lithography method to fabricate microfluidic devices out of MY133-V2000, a UV-curable, fluorinated polymer with low refractive index that is close to that of water (n = 1.33). The primary challenge in the use of this material (and fluorinated materials in general) is the low adhesion of the fluorinated material; we present several alternative fabrication methods we have tested to improve inter-layer adhesion. The close match between the refractive index of this material and aqueous solutions commonly used in biomedical applications enables fluorescence imaging at microchannel or other microfabricated edges without distortion. The close match in refractive index also enables quantitative phase microscopy imaging across the full width of microchannels without error-inducing artifacts for measurement of cell biomass. Overall, our results demonstrate the utility of low-refractive index microfluidics for biological applications requiring high-precision optical imaging.     

New horizontal frustum optical waveguide fabrication using UV proximity printing

This paper presents a novel method for fabricating the horizontal frustum structure as a planar optical waveguide using the proximity printing technique. A horizontal frustum optical waveguide with both lateral and vertical taper structure was produced. The orthogonal and inclined masks with the diffraction effect were employed in the lithography process. This method can precisely control each horizontal frustum optical waveguide geometric profile in the fabrication process. The horizontal frustum optical waveguide and its array with the same inclined angle were generated. The beam propagation simulation software (BPM_CAD) was used to model the optical performance. The simulation results reveal that the mode profile matched into horizontal frustum optical waveguide and fiber from the laser diode. The optical loss of the horizontal hemi-frustum optical waveguide structure was less than 0.2 dB. The horizontal hemi-frustum waveguide will be used for fiber coupling on boards for future optical communication systems.     

Interaction of guided light in rib polymer waveguides with dielectrophoretically controlled nanoparticles

This work demonstrates an optofluidic system, where dielectrophoretically controlled suspended nanoparticles are used to manipulate the properties of an optical waveguide. This optofluidic device is composed of a multimode polymeric rib waveguide and a microfluidic channel as its upper cladding. This channel integrates dielectrophoretic (DEP) microelectrodes and is infiltrated with suspended silica and tungsten trioxide nanoparticles. By applying electrical signals with various intensities and frequencies to the DEP microelectrodes, the nanoparticles can be concentrated close to the waveguide surface significantly altering the optical properties in this region. Depending on the particle refractive indices, concentrations, positions and dimensions, the light remains confined or is scattered into the surrounding media in the microfluidic channel.     

Development and characterisation of integrated microfluidics on waveguide-based photonic platforms fabricated from hybrid materials

This article reports on a detailed investigation of sol–gel processed hybrid organic–inorganic materials for use in lab-on-a-chip (LoC) applications. A particular focus on this research was the implementation of integrated microfluidic circuitry in waveguide-based photonic sensing platforms. This objective is not possible using other fabrication technologies that are typically used for microfluidic platforms. Significant results on the surface characterisation of hybrid sol–gel processed materials have been obtained which highlight the ability to tune the hydrophilicity of the materials by careful adjustment of material constituents and processing conditions. A proof-of-principle microfluidic platform was designed and a fabrication process was established which addressed requirements for refractive index tuning (essential for waveguiding), bonding of a transparent cover layer to the device, optimized sol–gel deposition process, and a photolithography process to form the microchannels. Characterisation of fluid flow in the resulting microchannels revealed volumetric flow rates between 0.012 and 0.018 μl/min which is characteristic of capillary-driven fluid flow. As proof of the integration of optical and microfluidic functionality, a microchannel was fabricated crossing an optical waveguide which demonstrated that the presence of optical waveguides does not significantly disrupt capillary-driven fluid flow. These results represent the first comprehensive evaluation of photocurable hybrid sol–gel materials for use in waveguide-based photonic platforms for lab-on-a-chip applications.     

Novel miniature integrated optical goniometers

A new principle and arrangement for directly determining the angle of incidence of an optical beam on an object are proposed and demonstrated. The novelty of the approach lies in the realization of a ‘smart object’, which extracts a portion of the incident beam's power into an optical waveguide attached to the object's surface or embedded in its body for converting the angle of incidence into the position of a guided beam with finite lateral extent. This ‘integrated optical light pointer’ beam is accomplished by means of creating additional degrees of freedom on the target in two different ways. While a first type is based on introducing spatial variations of the waveguide thickness, a second type makes use of a chirp of the grating periodicity. The feasibility for practical applications has been experimentally demonstrated by a direct comparison with a commercial high-resolution encoder, resulting in an r.m.s. error of <30′'. Measurements have been performed for chips fabricated based on replicated polycarbonate substrates and with no external optics, showing the great potential of this approach for realizing low-cost yet high-performance miniature goniometers.     

Fabrication of two dimensional high aspect ratio polymer photonic crystal laser

Photonic crystals have attracted much attention from researchers because of the control over the propagation and emission of light and particular optical properties. In this paper, we reported on the design, fabrication and test of a two-dimensional polymer photonic crystal laser. First of all, a two-dimensional polymer photonic crystal laser with a triangle-lattice structure was described. Rhodamine 6G doped in PMMA was chosen as the gain material. Then, plane wave method based on the Maxwell equations was utilized to calculate the distribution of the photonic band gap. We calculated the band structure of a triangle lattice photonic crystal with a low refractive index. High resolution electron beam lithography combined with electroplating was used to fabricate the silicon nitride mask. A high aspect ratio two-dimensional photonic crystal laser was fabricated by X-ray lithography in one-step process to overcome the limitation of the thickness by the conventional methods to realize a real two-dimensional laser. Meanwhile, processes of sample preparations and fabrication were optimized in order to avoid the oxidation of the gain material and reduce the diffraction effect on the structures.     

Micro- and integrated optical devices in glasses and polymers for hybride integration into microsystems

Micro- and integrated-optical devices in glass and polymers are integrated increasingly in microsystems. Design and simulation of such optical elements are well developed. Ray tracing and a manifold of propagation and field calculation methods are available. First steps to CAD have been done.Using Ag⁺–Na⁺ ion exchange in special optical glasses, one-and two-dimensional refractive index profiles of definite shape have been realezed. Good quality one-dimensional profiles can be used for micro-cylindrical lens fabrication (N.A.0.5), two dimensional index gradients have been used for phase grating fabrication. E-beam direct writing with variable shaped beam has been used successfully to realize different types of surface corrugated microoptical components. Embossing in polymers is a well suitable method for fabrication of passive integrated-optical devices and of micro-optical elements as refractive and diffractive lenses and lens arrays, corrugated prisms and gratings. Applications of glass and polymer microoptical devices have been demonstrated for laser diode collimation, in miniaturized interferometers, beam deflectors and modulators.     

Development of 2D Microdisplay Using an Integrated Microresonating Waveguide Scanning System

Our research team has developed a 2D micro image display device that can potentially overcome the size reduction limits while maintaining the high-image resolution and field of view obtained by mirror-based display systems. The basic design of the optical scanner includes a microfabricated SU-8 cantilever waveguide that is electromechanically deflected by a piezoelectric actuator. From the distal tip of the cantilever waveguide, a light beam is emitted and the direction of propagation is displaced along two orthogonal directions. The waveforms for the actuator and the LED light modulation are generated and controlled using a field programmable gate array. Our recent study is an update to the previously-reported mechanical scanner, replacing the hand-built PZT scanner and fiber waveguide with a microfabricated system incorporating aerosol-deposited PZT thin film and a polymeric SU-8 wave guide. In this article, we report on the design and fabrication of a prototype miniaturized 2D scanner, discuss optical and mechanical the modeling of the system's properties and present the experimental results.