一种用于微镜阵列投影测试的系统设计

在微镜器件的研制过程中,对其光学特性的测试需要借助很多仪器和测试平台,测试过程比较繁琐,测试成本也很高。设计了一种用于微镜阵列测试的电路系统,利用该系统可以将微镜阵列的工作状态以投影的方式显现出来,以便进行直观有效的测试。该测试电路以STM32微控制器为控制核心,用UHP灯(高压汞灯)和色轮作为投影光源,驱动AMD(先进微镜器件)的微镜阵列进行投影,相当于一个简洁的投影机控制主板,其特点是简单、实用、可靠性好。     

用于大型低温环境下多目标光谱仪的微镜阵列

下一代空间天文仪器与地基望远镜需要基于MOEMS的可编程狭缝模具．该模具用于必须工作在低温环境下的多目标光谱仪（MOS）。1个5x5单晶硅微镜阵列（MMA）的初等模型已经成功地制作与检测。100μm×200μm微镜可以通过静电驱动倾斜,产生20~机械倾角。在低温制冷前后温度低于100K的情况下,微镜阵列已经被成功驱动。1个微镜阵列包括2个不同的芯片：镜面芯片与电极芯片,分别制作在硅绝缘体基片上。为了组装大型阵列（100×200微镜）．需要高精密的装调与人工处理抑制。本文为此装置发展了1种组装技术,并设计与制作出专用的XY朋斜平台。这个平台允许以微米量级的精度向微镜方向调准电极。大型100×200微镜阵列可以用于大视场,测量范围为25mm×25mm。通过使用上述设备,已经成功地制作和组装了微镜阵列,并且未检测到组装引起的变形。检测到的微镜形变的峰谷值为14nm,已经进行了初步的驱动测试。     

基于MEMS技术的全光热成像芯片与系统的研制

提出了一种新颖的非致冷光读出热成像芯片的设计,其核心部分是一个m×n的可动微镜阵列,可动微镜是由双材料弯折梁及其所支撑的微镜面组成.在红外辐射的作用下,梁发生弯曲带动微镜面发生的位移变化对输出可见光的强度进行调制,即利用光调制原理完成光信号转换和增强.采用体硅MEMS技术,成功地制作出了50×50的可动微镜阵列.测试表明:工艺一致性和残余应力对释放前后可动微镜表面粗糙度与平整度、可动微镜间初始相位以及可动微镜灵敏度的大小产生了重要影响.     

基于MEMS技术的全光热成像芯片与系统的研制

提出了一种新颖的非致冷光读出热成像芯片的设计,其核心部分是一个m×n的可动微镜阵列,可动微镜是由双材料弯折梁及其所支撑的微镜面组成.在红外辐射的作用下,梁发生弯曲带动微镜面发生的位移变化对输出可见光的强度进行调制,即利用光调制原理完成光信号转换和增强.采用体硅MEMS技术,成功地制作出了5 0×5 0的可动微镜阵列.测试表明:工艺一致性和残余应力对释放前后可动微镜表面粗糙度与平整度、可动微镜间初始相位以及可动微镜灵敏度的大小产生了重要影响     

一种用于激光屈光术的新型激光光斑调制系统

激光光调调制装置包括－高分辨率的微镜阵列,后者由许多独立编址并且可移动的微镜构成。微镜在打开位置反射部分光束到角膜,在关闭位置反射光束偏离角膜。针对一系列的预定模式进行编程后,计算机可控制某些微镜移动到打开位置,而其它的微镜处于关闭位置。每个消融模式叠加起来构成矫正角膜折射率偏差的形成。并且由于微镜阵列的高分辨率,此形线非常平滑,这对减轻激光屈光术后的角膜浑浊程度是有利的。     

基于数字微镜阵列的平顶光束空间整形

为了满足激光光斑质量高、扫描快速的目的,采用数字微镜阵列和误差扩散法对单平顶和多平顶的光束整形原理仿真,利用680nm激光建立了实验系统,并进行了光束整形验证。采用光束填充因子、光场调制度、均方根误差3种评价参量对整形结果进行评价,并对采用数字微镜阵列进行光束整形的能量利用率进行了测量和分析。结果表明,单平顶和多平顶整形的光束填充因子由整形前的36.1%分别提高到62.3%和56.7%;光场调制度由73.3%分别降到25.6%和30.3%。利用该光束空间整形方法,可得到高质量的多平顶光束,在快速激光扫描领域有一定的应用价值。     

数字微镜阵列红外动态景象模拟器的研制

红外动态景象模拟器为红外半实物仿真系统提供动态目标和背景,是半实物仿真系统的核心技术之一.介绍了基于数字微镜阵列研制的红外动态景象模拟器的组成、工作原理和技术指标.描述了数字微镜阵列红外动态景象模拟器的4大关键技术,即红外图像转换技术,红外图像转换器的同步调制驱动技术,红外光学耦合技术和红外热像逼真度修正技术.分析了红外图像转换器同步与不同步驱动对图像采集的影响.给出了经研制的数字微镜阵列景象模拟器产生、红外热像仪获取的红外图像.实验结果表明:该模拟可广泛应用于红外成像探测系统的仿真、测试和标定.     

16×16光开关微镜阵列

设计、制造和测试了一种实现16×16 MEMS光开关的高反射率、大角度静电扭转制动型微镜阵列.该阵列的微镜可进行90扭转并保持稳定的扭转状态以对入射光进行导向.针对微镜的扭转驱动特性,提出了相应的机电模型.通过单片集成光纤槽,实现了光纤.微镜.光纤的无源对准.测试结果表明,微镜反射率为93.1%～96.3%,最低插入损耗为2.1dB,另外,在经过15min的5～90Hz,3mm振幅的振动测试后,光开关的插入损耗的改变值仅为±0.01dB.     

16×16光开关微镜阵列

设计、制造和测试了一种实现16×16 MEMS光开关的高反射率、大角度静电扭转制动型微镜阵列.该阵列的微镜可进行90扭转并保持稳定的扭转状态以对入射光进行导向.针对微镜的扭转驱动特性,提出了相应的机电模型.通过单片集成光纤槽,实现了光纤.微镜.光纤的无源对准.测试结果表明,微镜反射率为93.1%～96.3%,最低插入损耗为2.1dB,另外,在经过15min的5～90Hz,3mm振幅的振动测试后,光开关的插入损耗的改变值仅为±0.01dB.     

一种制作凹形聚二甲基硅氧烷微透镜阵列的方法

提出一种制作凹形聚二甲基硅氧烷(PDMS)微透镜阵列的方法。用数字微镜器件(DMD)代替物理掩模,建立数字灰阶无掩模光刻系统,在光刻胶上制作正方形基底凸形微透镜阵列,以此阵列为母板,采用复制方法,制作了高填充因子的正方形基底凹形PDMS微透镜阵列。实验和测试结果表明:数字灰阶无掩模光刻系统制作的微透镜阵列表面光滑,形貌良好;复制的PDMS微透镜阵列边缘清晰,表面光滑,焦面光斑光强均匀。为制作凹形微透镜阵列提供了一条制作简单、效率高、成本低、可大规模制作的新途径。     

微反射镜阵列在光束整形中的应用

在激光的实际应用中,需要利用光束整形技术将激光器的输出光束调制为期望的光强分布。微机电系统的发展为光束整形提供了一种解决方案。采用微反射镜阵列,实现了激光光束的整形。基于随机化的思想提出了相应的算法,分析了算法在不同单元数目和不同噪声水平下的表现,为实际应用提供了有价值的参考依据。最后,建立了实际的光路模型,进行了光线追迹,给出单模高斯光束以及考虑噪声情况下的仿真结果。分析结果表明,使用微反射镜阵列可以有效地实现不同输入下的激光光束整形,并且具有极大的灵活性,为光束整形提供了一种新的手段。     

MEMS optical wavelength deinterleaver with continuously variable channel spacing and center wavelength

We report on a tunable optical wavelength deinterleaver based on a microelectromechanical system micromirror array in a modified Gires-Tournois interferometer. Continuous wavelength tuning and switching of the deinterleaver outputs are achieved by vertical micromirror motion of less than 1 /spl mu/m. Control of the channel spacing, or free spectral range of the device, is also experimentally demonstrated.     

A Novel 4$, times ,$4 Optical Switch Using an Anisotropically Etched Micromirror Array and a Bistable Mini-Actuator Array

This letter presents a novel approach to realize a 4 times 4 optical switch. The optical switch consists of a micromachined silicon micromirror array and a bistable mini-actuator array. The micromirror array, which comprises vertical mirrors, cantilevers, and trenches, can be monolithically fabricated by a simple anisotropic silicon etching process in high precision and high yield. The mini-actuator array consists of 16 commercially available bistable actuators integrated with L-shape arms. The advantages of this approach include high precision, easy alignment, high fabrication yield, and low cost. Because of bistable actuation, the power consumption is very low and thus the temperature elevation of a working device is less than 0.3 K. The measured insertion losses of the four channels are between - 1.6 and - 2.3 dB. The measured crosstalk is less than -60 dB, and the measured switching time is about 13 ms.     

Performance of a raster scanning laser display system using diamond shaped frame supported micromirror

We describe the design, fabrication, and experimental results of a raster scanning laser display system using micromachined electrostatic scanning micromirror. The micromirror is comprised of a diaphragm mirror plate supported by an array of diamond shaped support frame, and movable comb electrodes. A prototype raster scanning laser display system using the fabricated micromirror, having optical scan angle of 16.9/spl deg/ at resonance frequency of 19.55 kHz, as the horizontal scanner was developed and tested. To compensate for the nonlinear characteristics of the scanner, a simple image correction method was developed, and the projected image was analyzed and compared with the simulation results.     

Design and Simulation of Silicon-based NiCrAu MEMS Torsion Micromirror with Tilted Back-electrode

Torsion micromirror is a key structure of optical devices in micro-electro-mechanical system (MEMS), such as MEMS optical switches, MEMS variable optical attenuator, MEMS scanning micromirror array and so on. A silicon-based NiCrAu MEMS torsion micromirror is theoretically analyzed. It is shown that in order to have 15~ rotation, the driven voltage should be about 20 V and the thickness of the supporting beam must be controlled in the range of submicron orders of magnitude. This very thin beam makes the structure more unstable and unreliable, and also makes the fabrication more complicated. Based on parallel backelectrode analysis and testing, a tilted back-electrode has been designed to replace the parallel back-electrode in order to decrease the driven voltage and difficulty of fabricating processing. By theoretical analysis and simulation, a conclusion can be drown that the thickness can be improved from submicron to micron by using tilted back-electrode when using the same driven voltage. Tilted back-electrode is very effective to improve the stability and reliability of the micromirror structure.     

Large-Stroke Microelectrostatic Actuators for Vertical Translation of Micromirrors Used in Adaptive Optics

Two microelectrostatic actuators able to produce a repulsive force in the out-of-plane direction are presented in this paper. The electrostatic actuators use an asymmetric electric field surrounding the top and bottom surfaces of the moving fingers to produce a repulsive force. The displacement of translation micromirrors driven by these actuators is not limited by the “pull-in” effect and, therefore, can achieve a large stroke. In addition, the usage of a repulsive force leads to the elimination of the stiction problem. An analytical model relating the displacement of the first actuator to voltage applied is presented. The analytical model and numerical simulations show that a translation micromirror driven by the first actuator can achieve a stroke as large as 6$muhboxm$at a driving voltage of 50 V. The second actuator, suitable for fabrication using Multi-User-MEMS-Processes (MUMPs), is developed. A prototype translation micromirror driven by the second actuator achieved a vertical stroke of 2$muhboxm$, which is more than three times the stroke of conventional MUMPs translation micromirrors.     

Microoptical phased arrays for spatial and spectral switching

This article describes two optical devices based on linear arrays of micromirrors. The first is a phased array of micromirrors that can be rotated as well as translated vertically to maintain coherence across the array. We demonstrate experimentally that such micromirrors are capable of high-diffraction-efficiency phased-array scanning of laser beams. The second device is a Gires-Tournois (1969) interferometer with a micromirror array that provides tunable phase modulation for the multitude of partially reflected beams within the interferometer. We demonstrate experimentally that the MEMS-GT interferometer can operate as a tunable deinterleaver for dense wavelength-division multiplexed fiber optic communication.     

A high port-count wavelength-selective switch using a large scan-angle, high fill-factor, two-axis MEMS scanner array

We present a high-port-count (scalable to 1 /spl times/ 32) wavelength-selective switch (WSS) using a large scan-angle, high fill-factor, two-axis analog micromirror array in conjunction with a densely packed two-dimensional array of fiber collimators. A partially populated (1 /spl times/ 9) WSS exhibits a fiber-to-fiber insertion loss of 5.57 /spl plusmn/ 1.4 dB and an extinction ratio of 51 /spl plusmn/ 11 dB. The channel spacing is 100 GHz.     

Neural Network Approach for Linearization of the Electrostatically Actuated Double-Gimballed Micromirror

In this paper, a hierarchical circuit based approach is used for the development of a reduced-order macro-model for a double-gimballed electrostatic torsional micromirror. The nonlinearity and cross-axis coupling of the micromirror subjected to the differential driving scheme are investigated using the proposed macro-model. The simulation results are used to train a feed-forward neural network which carries out a function approximation of the relation between the desired location and the required driving voltages. The trained neural network is then coded into MAST AHDL. System-level simulation of the micromirror together with the neural network is performed in the SABER simulator. It is found that using a feed-forward neural network, the linearity of the micromirror is greatly improved, the steady state of the cross-axis coupling is reduced to a negligible level and the transient response of the cross-axis coupling is also suppressed. This implies that introducing a feed-forward neural network would be useful to simplify the design of the feedback control system for the double-gimballed electrostatic torsional micromirror.