聚合物光栅光波导器件的微复制技术

采用纳米压印微复制技术方法,研制了一种新型的聚合物柔性光栅光波导敏感器件,该器件可用于介入式医用导管的微弯挠曲监测或类似场合的微变形监测.重点阐述了聚合物柔性光栅光波导器件的微复制模具和器件微复制的工艺方法,并对制备工艺技术中的关键技术问题进行了讨论,讨论了测试光纤耦合一体化光栅波导器件的工艺方法.最后利用硅微模具和紫外固化介质材料,成功制备出了截面尺寸为4 μm×20 μm、光栅周期为0.75 μm的聚合物柔性光栅光波导器件.     

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.     

微弯光纤传感器位移灵敏度研究

根据光纤模式耦合理论,光纤微弯时光纤中的传输光有光功率损耗,对微弯光纤传感器出射光强进行分析、测量,实验得出了位移灵敏度与微弯周期的关系,对应用微弯光纤组成分布式光纤测试系统的传感器具有重要意义。     

一种缺陷态光子晶体的气敏传感理论研究

利用Bruggeman介电常数近似理论,毛细冷凝作用以及一维光子晶体传输矩阵的理论分析方法,对多孔硅微腔被一定浓度的有机物蒸汽吸附时的传感特性进行了深入地研究,建立了其光学传感模型,并用计算机数值模拟的方法对多孔硅微腔的传感模型进行了理论仿真,得出了饱和情况下有机物蒸汽折射率与峰位漂移量间的线性关系以及乙醇蒸汽浓度与微腔反射谱透射峰峰位漂移量间的函数关系曲线,为多孔硅微腔传感元件的设计和应用提供了理论基础.     

等离子硅刻蚀及其工艺参数的多尺度优化

用CFD-ACE+和CFD-TOPO分别对容性耦合等离子体反应腔室放电和等离子硅刻蚀过程进行仿真,讨论不同射频电压和腔室条件对等离子体特性的影响.结果表明:随着射频电压的升高,离子的通量增大;在低射频电压时,离子通量随腔室压强的升高而减小,而在高射频电压时趋势则相反.用Kriging模型对影响刻蚀形貌的参数(腔室压强和射频电压)进行优化,结果表明该优化方法可以为工艺条件相近的刻蚀机设备的设计提供参考.     

MEMS密闭腔内微气流的挤压膜阻尼效应研究

针对MEMS密闭腔内微气流与压电驱动机构的耦合振动,综合采用空气挤压膜阻尼效应和能量法进行理论分析。根据等温雷诺方程求解气体压力分布,进而计算微气流挤压膜阻尼能,将其代入能量方程,与压电-硅膜的耦合动能、势能、压电电场能进行能量耦合,将由能量方程确定的压电-硅膜-微气流耦合作用下的位移振形待定系数λ′与无气流影响下的压电-硅膜耦合振动位移振形待定系数λ对比后,找到了增加的阻尼项,微气流对驱动结构振动位移的影响正是通过该阻尼项体现的。研究可为微流体的驱动及协调控制提供相关理论基础及控制策略。     

微机械陀螺的刻蚀误差特性分析

微陀螺仪结构上的腐蚀凹槽或腐蚀腔可以由深层反应离子刻蚀技术得到,加工过程中存在的刻蚀误差对微陀螺的固有频率、输出精度和稳定性有重要的影响.采用有限元分析软件ANSYS建立了一种梳状微机械陀螺的有限元分析模型,采用解析的方法并通过Matlab数学软件进行仿真,研究了由于加工误差导致微梁过度刻蚀对微陀螺驱动模态、检测模态、固有频率、带宽、灵敏度的影响.结果表明,微梁刚度和微陀螺固有频率随着刻蚀角度的增大而增大;最大过度刻蚀角度为±2度时,其驱动模态和检测模态的固有频率的变化率均超过了14%;刻蚀误差会导致微陀螺工作模态降阶,以及干扰模态介于与驱动和检测模态之间且与驱动模态频率相近,这会严重影响微陀螺的输出精度;带宽随过度刻蚀夹角增大而减小,灵敏度随过度刻蚀夹角的变化而发生不规律变化;当刻蚀角度介于0°~1.5°时,微陀螺的灵敏度将高于无刻蚀误差时微陀螺的灵敏度.     

一种基于多孔硅微腔光学特性的气体传感器的研究

当有机物分子吸附到多孔硅表面时,由于有机物分子在多孔硅的孔内的毛细冷凝作用,将引起多孔硅层有效折射率的变化,从而导致多孔硅微腔反射谱吸收峰峰位的变化.本文主要利用Bruggeman介电常数近似理论与传输矩阵的方法,建立了多孔硅微腔的传感模型.使用多孔硅微腔的反射谱实验装置对多孔硅微腔进行了传感实验,结果证明多孔硅微腔传感元件可以实现对有机物蒸汽的检测,且分辨率较高,响应时间和恢复时间短,可重复性好.     

压阻式硅微加速度计的研制

介绍压阻式硅微加速度计的结构设计。采用等离子体刻蚀技术制作成硅微加速度计。该技术具有腐蚀深宽比高、掩模选择性好的特点,适用于微机械器件的制作。通过测试,加速度计的非线性达到0.2%。讨论了影响加速度计灵敏度的结构因素和工艺因素。     

光纤耦合光动力传感器的研究

介绍一种微功耗敏感探头的原理以及光纤耦合光动力工作的方法。采用５００ｍ长的光纤传输ＬＤ光功率，其出纤功率达３ｍＷ，可使小于１００μＷ功耗探头稳定可靠工作。     

Hole-type two-dimensional photonic crystal fabricated in silicon on insulator wafers

We report the realization of two-dimensional (2D) photonic crystal (PhC) holes array using synthesized processing techniques of deep UV lithography, time-multiplexed reactive ion etching (TMRIE) and focus ion beam (FIB) etching. In this study, mixed density of holes and waveguide patterns of 2D PhC structures was first formed in silicon on insulator wafers through use of a scanner. Ultra wide grooves were then defined, aligned to the deep submicron size devices. Following deep etching of more than 50 μm by TMRIE, PhC structures were then revealed for device etching. Such design of fabrication process allows realization of disparate pattern dimensions and also etching depths. Through avoidance of etch lag effect, notching of devices at interface of device silicon and buried oxide layer was avoided. At the same time, through a singular FIB etch in the final step of the process following buried oxide release for PhC structures on critical dimension structures, severe loading effects of such structures were avoided to enable a wide process window of lithography and etch.     

新型高灵敏抗冲击集成光学加速度计

提出一种新型基于微环谐振腔的集成光学加速度计,该加速度传感器具有较高的灵敏度(56.6 mV/gn)和良好的抗冲击性能(可达105gn)。介绍并分析了该加速度计的传感理论,建立了微环谐振腔耦合单元模型,通过Matlab软件和时域差分有限元(FDTD)法绘制了波导的模态传输曲线,优化了微环谐振腔的设计参数和微腔与波导的耦合间距,并且利用ANSYS给出了悬臂梁的承受冲击极限。最终,仿真结果与理论分析结果基本一致。该加速度计可为高灵敏抗冲击微光机电系统(MOEMS)传感器提供新思路和理论参考。     

A 1-D Photonic Band Gap Tunable Optical Filter in (110) Silicon

In this paper, we describe an electrostatically tunable optical bandpass filter that is fabricated in (110) silicon. Deep reactive-ion etching is the main process that is used to fabricate the overall device structure. To create the highly parallel surfaces that are needed for the photonic band gap elements, electrochemical (KOH) etching of the vertical (111) planes is then used. Back etching is used to release the moving parts. Fiber pigtails are attached in etched alignment grooves, and fiber-fiber insertion loss below 11 dB was obtained. The measured passband width was 3 nm with a tuning range of 8 nm.     

Vertical mirrors fabricated by deep reactive ion etching forfiber-optic switching applications

We report on vertical mirrors fabricated by deep reactive ion etching of silicon. The mirror height is 75 μm, covering the fiber core of a single-mode fiber when the latter is placed into a groove of equal depth and etched simultaneously with the mirror. To obtain a uniform etch depth, etching is stopped on a buried oxide layer. Using the buried oxide as a sacrificial layer allows to fabricate mirrors with suspension and actuation structures as well as fiber-alignment grooves in one and the same processing step. A minimal mirror thickness of 2.3 μm was achieved, resulting in an aspect ratio higher than 30. The verticality was better than 89.3°. In the upper part of the mirror a surface roughness below 40 nm rms was obtained. At a wavelength of 1300 nm the reflectivity of the aluminum-coated mirrors was measured to be higher than 76%. Using a reactive ion etched mirror we have fabricated an optical fiber switch with electrostatic actuation. The coupling loss in the bar state of two packaged prototypes was between 0.6 and 1.7 dB and between 1.4 and 3.4 dB in the cross state. The switching time is below 0.2 ms     

An analytical coupling coefficient for MEMS tunable silicon nanowire waveguide coupler devices

Silicon nanowire waveguides are promising for future integration of photonic circuits with silicon electronics. Electromechanical control of waveguide is also favorable for variable silicon nanowire waveguide devices. In this study, we investigated analytically the characteristics of a silicon nanowire waveguide coupler for electromechanical waveguide devices. The electric field of the silicon nanowire waveguide was enhanced by the high-index contrast. The enhanced electric field increased the coupling coefficient by a factor of 2.7 for a silicon waveguide of 400 nm in width and 260 nm in thickness compared with the approximation on the basis of low-index-contract. The analytically derived coupling coefficient was evaluated experimentally by investigating a waveguide coupler switch with a micro-electromechanical actuator.     

Sacrificial wafer bonding for planarization after very deep etching

A new technique is presented that provides planarization after a very deep etching step in silicon. This offers the possibility for resist spinning and layer patterning as well as realization of bridges or cantilevers across deep holes or grooves. The sacrificial wafer bonding technique contains a wafer bond step followed by an etch back. Results of polymer bonding followed by dry etching and anodic bonding combined with KOH etching are discussed. The polymer bonding has been applied in a strain based membrane pressure sensor to pattern the strain gauges and to provide electrical connections across a deep corrugation in a thin silicon nitride membrane by metal bridges     

MEMS on silicon for integrated optic metrology and communication systems

 Integrated optic micro-electromechanical systems (IO-MEMS) based on silicon-, Al₂O₃-SiO₂ and TiO₂-SiO₂ waveguides, doped with Ti, Cr, and Er on silicon substrates allow to generate complex metrology and optical communication systems. They exhibit low loss across a wide spectral range, occupy small space, and exhibit high functionality at low production cost. The waveguides are deposited by CVD and patterned by anisotropic plasma etching. The micro-electromechanical structures are formed by standard micro-machining processes and anodic bonding of silicon-glass. An integrated optical pressure sensor using the interferometer principle, a gas monitor for the near and middle infrared using elevated silicon single mode waveguides, an electrostatic-tuned Ti:/Cr:-sapphire laser, and a UV-VIS-NIR-spectrometer including integrated broad banded light sources represent metrology systems. Optical communication systems are described like a waveguide grating based wavelength demultiplexer, an optical transceiver using self aligned detector and emitter as well as a tapered fibre coupler, and an integrated optical amplifier. Received: 10 July 2001/Accepted: 15 August 2001 This work was funded by Deutsche Forschungsgemeinschaft, the Ministry of Research and Technology and the City of Hamburg. This paper was presented at the Workshop “Optical MEMS and Integrated Optics” in June 2001.     

基于FPGA的光学微腔生物传感器控制系统

为了促进光学微腔生物传感技术向集成化、智能化和小型化发展,提出了一种基于现场可编程门阵列(FPGA)的数字辅助控制系统.系统通过三角波信号驱动可调谐激光器进入连续扫描模式,周期性扫描光学微腔谐振波长,得到激光中心波长信号的偏移量,从而得到光学微腔的灵敏度.设计了控制系统的硬件电路及软件辅助程序.经实验验证表明:控制系统实现了光学微腔生物传感器的数据采集处理以及对激光器的调谐.     

Bulk silicon holding structures for mounting of optical fibers inv-grooves

A set of micromachined structures for holding optical fibers in anisotropically etched v-grooves has been produced. The structures are made of bulk silicon and formed in the same etch step as the aligning v-grooves, using the photovoltaic electrochemical etch-stop technique (PHET). It is a selective etch method where n-type silicon etches and p-type are passivated by combining an illuminated pn-junction and an electrochemical cell using KOH as electrolyte. The structures were produced in a variety of shapes, based on cantilever beams and doubly clamped bridges. The structures substantially facilitated the mounting of the fibers into the v-grooves. Certain structures could even push the fibers down into position in the grooves     

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...