This PDF file contains the front matter associated with SPIE Proceedings Volume 6836, including the Title Page, Copyright information, Table of Contents, Introduction, and the Conference Committee listing.

In this paper, four different types of miniaturized Microelectromechanical Systems (MEMS) based tunable lasers, from photonic MEMS laser designs to fabrication techniques, are introduced. These tunable lasers are MEMS external cavity laser, injection-locked laser, coupled-cavity laser, and dual-wavelength laser. The properties, functionalities and performances of the MEMS-based tunable lasers are individually discussed based on their experimental results. The potential applications in fiber optical communications are also identified. These tunable lasers, which are more innovative in terms of design, specifications and configurations compared to traditional lasers, also provide significant improvements in their functionalities.

This paper presents the design, fabrication and performance of a 1×2 piezoelectric optical switch. The optical switch is developed based on the concept that the input fiber is directly moved by the deflection of a piezoelectric tube actuator. The piezoelectric tube actuator used in this switch is manufactured through an electrophoretic deposition process. The tube is inexpensive to produce and compact in size with high mechanical performance. It has a maximum deflection of 30μm which is capable to actuate the input fiber for switching. The multimode fiber optical switch has been successfully assembled. To reduce the misalignment loss between the fibers, the output fibers are precisely aligned in silicon vgrooves. Different components are bonded with low shrinkage adhesive in order to minimize their position inaccuracy. The performance characteristics of the optical switch have been measured, with an insertion loss of 1dB, crosstalk of -45dB and switching speed from 5 to 10ms. The switch also shows good reliability and requires small driving power. The development of multimode optical switch prototypes proves that the idea of piezoelectric switching is feasible. Further developments include the improvement of switching performance, reduction of the prototype size and the fabrication of multiple output prototypes.

In this paper, a new method for interconnecting free-space micro-optoelectromechanical system (MOEMS) devices is developed. The heterogeneous design and assembly concept is demonstrated by a pair of V-shape actuators and related assembly mechanism, fabricated on a silicon-on-insulator (SOI) wafer. A two-channel free-space DWDM filter has been assembled and characterized. The results show low insertion losses. The device architecture allows hybrid optical system integration on a single platform. The assembled optical devices can be made of different materials, on different substrates and/or with incompatible fabrication techniques. The integration platform provides potentials for realizing a micro optical bench with equivalent optical performance that currently require bulk optics setups.

Fabrication of flat, free-standing silicon diaphragms as micromirrors using etching processes is the key in the development of optical Micro-Elecro-Mechanical System(MEMS) devices, such as tunable F-P(Fabry-Perot) filters. It is very important for etching process to get smooth surface and uniform depth because they greatly affect the performance of the final device. In this paper, we report the experimental results about roughness and flatness of silicon micromirror fabricated by wet and dry etching processes. The investigated process involved wet-etching process in self-prepared KOH solution, and dry etching process with such machines as ALCATEL 601E DRIE(Deep Reactive Ion Etching) and STS ICP (Inductivity Coupling Plasma). It was found that wet etching process could supply more uniform etching depth, whereas the better surface roughness was gotten by dry etching. For a 30μm target depth, surface roughness less than 3-nm and maximal depth difference less than 0.3-μm were obtained by STS ICP and KOH respectively.

Optical MEMS components with optical fiber inputs and outputs are the most important kinds of optical MEMS devices because of their applications in optical communication industry and fiber-optic sensors. Efficient optical coupling is the key to develop optical MEMS devices for optical communication and sensing, however, efficient coupling between MEMS actuators or sensing structures and optical fibers is a challenging job. Besides high performance MEMS actuators and coupling micro-optics are needed, the MEMS structures should adapt to coupling micro-optics. The torsion MEMS micro-mirrors and gratings can couple with fiber collimators at low insertion loss, therefore, the torsion MEMS structure is a good choice for optical MEMS devices, especially for continuous or multi-level controlled devices. In this paper, we report three kinds of optical MEMS devices based on silicon torsion micro structure, MEMS variable optical attenuator (VOA), 1×8 MEMS optical switch and high-speed MEMS torsion blazed grating , which have been developed recently in our optical MEMS research group. The three devices are coupled with optical fibers by optical fiber collimators, so low loss coupling can be achieved.

Linear fiber-optic image slicer is used more and more in spatial exploration and imaging system. In this paper, a plane arranging method of fiber-optic array based on Si-V grooves is established in order to improve the accuracy and reduce the cost of manufacturing. Firstly, the Si-V groove array is micro-machined with anisotropic etching process, then optical fibers are placed in the grooves orderly with plane arranging method. Secondly, the end surfaces of the device are polished, also the linear fiber-optic image slicer is packaged. Finally, some parameters are tested, including structure parameters, transmittivity and vibration test. Experimental results indicate that the maximum error accumulated in 2000 periods of the Si-V grooves is 0.5μm, the error of the height in Si-V grooves is less than 0.15μm, the roughness of the end surface is less than 0.9nm. The transmittivity of the linear fiber-optic image slicer that without optical film is 51.46% at the wavelength of 632.8nm. After random vibration experiment, the ratio of the broken fiber increased by 0.1%. While the temperature reached 320°C, the stress of epoxy will be 130Mpa, which is close to the limit resistance stress of 139Mpa, some cracks appeared.

This paper presents a new wavelength-selective switch by combining silicon micromaching and microassembly techniques. The 1×8 wavelength-selective switch (WSS) based on micro electro mechanical systems (MEMS) technology is proposed and fabricated with micro electromagnetic actuators, reflecting prisms and narrow-band thin films filters. And a 8×8 WXC prototype node is implemented by using 1×8 WSSs as building elements. The working principle and the configuration of the micro electromagnetic actuator are illuminated. By analysis, the property suits for the application when the inputs are 2V, and the best fiber-to-fiber insertion loss 5dB is gotten.

Large-scale micro-electromechanical systems (MEMS) scanning mirrors play a primary role in many fields of manipulating light beam scanning, such as rapid optical spectrum analyzers (OSAs) based on dispersive gratings using in near infrared (NIR) region. According to the applications, a high speed electromagnetically actuated MEMS scanning mirror with large mirror area of 9×6mm² has been developed. The MEMS scanning mirror chip, which is fabricated using bulk silicon micromachining process and electroplating technique, is immersed in a constant 365 mT magnetic field parallel to the coil plane and generates the maximum optical deflection angle of ±11.15° at the 1.39 kHz resonant frequency. The quality factor, Q, of 77 is achieved in air corresponding to a low power consumption of 102.6 mW. In addition, the surface roughness of less than 20nm for scanning mirror has been measured and the optical reflectivity at the wavelength of 1550nm is high up to 87%. The results show that the device is adequate for mm-sized scanning systems and compatible with smart OSAs applications.

Liquid pumping, mixing and biological cells/reagents delivery in micro- or nano-liter volume is critical in lab-on-chip systems. We describe a novel AC electro-osmosis device for delivering reagents/cells over large distances without a global pressure gradient. Our device features facile transport range scalability in x- and y-axes, using continuous flow in a serpentine microchannel realized by microelectrode pairs arrayed in a unique antiparallel-asymmetric configuration. Co-planar microelectrodes on glass substrate are fabricated from gold with chromium as seed layer using micro-electromechanical system (MEMS) technology. Sealed upon the micro-electrodes is an open-ended serpentine microchannel having width 80μm and depth 45μm; formed by micromolding PDMS with a silicon-based mold. AC signals at 3.5V_pp and 0.5V DC offset is used to energize the microelectrodes, and polystyrene beads with diameter 5.0μm are used as tracer particles to visualize flow. Maximum velocity of 871 μm/s was recorded using AC signals at 8 kHz. The ease of scaling up transport distance range in 2-axes is unique to our device. Scalability in x-axis is achieved by varying the number of microelectrode pairs; and in y-axis by varying the number of microelectrodes iterations and the corresponding number of turns in the serpentine microchannel. Being scalable in transporting fluidic volume with high efficiency under small driving voltages makes our device suitable for miniaturization in a micro-total-analytical-system. Our device could be applied towards multiple point reagents, biological cells and particles delivery and mixing in a lab-on-chip.

In this article, a kind of microfluidic method based on MEMS technology combined with gold immunochromatographic assay (GICA) is developed and discussed. Compared to the traditional GICA, this method supplies us convenient, multi-channel, in-parallel, low cost and similar efficiency approach in the fields of alpha-fetopro-tei (AFP)detection. Firstly, we improved the adhesion between the model material SU-8 and Silicon wafer, optimized approaches of the fabrication of the SU-8 model systematically, and fabricate the PDMS micro fluid chip with good reproduction successfully. Secondly, Surface modification and antibody immobilization methods with the GICA on the PDMS micro fluid analysis chip are studied, we choose the PDMS material and transfer GICA to the PDMS micro fluid chip successfully after researching the antibody immobilization efficiency of different materials utilized in fabrication of the micro fluid chip. In order to improve the reaction efficiency of the immobilized antibody, we studied the characteristics of micro fluid without the gas drive, and the fluid velocity control in our design; we also design structure of grove to strengthen the ability of immobilizing the antibody. The stimulation of the structure shows that it achieves great improvement and experiments prove the design is feasible.

This paper proposes a method that using an electric field to improve the immobilization of analyte in an amperometric immunosensor. The amperometric immunosensor, which has a two-microelectrode system enclosed in a SU-8 reaction microwell, has been developed with MEMS technology for the detection of the human immunoglobulin (HIgG). Electric field has been applied above the working electrode by setting the appropriate potential between two electrodes to enable more antigen "IgG" to be assembled to the sensing interface with less time. The results demonstrate that the immunochemical incubation time spent on the immobilization of HIgG has been shortened, and the property of the immunosensor has been enhanced.

Uncooled infrared bolometer arrays have become the technology of choice for low-cost infrared imaging systems used in applications such as thermography, firefighting, driver night vision, security and surveillance. Uncooled infrared bolometer arrays are reaching performance levels which previously only were possible with cooled infrared photon detectors. With a continuously increasing market volume (> 100 000 units per year to date), the cost for uncooled infrared imaging chips are decreasing accordingly. In this paper we give an overview of the historical development of uncooled infrared bolometer technology and present the most important bolometer performance parameters. The different technology concepts, bolometer design approaches and bolometer materials (including vanadium oxide, amorphous silicon, silicon diodes, silicon-germanium and metals) are discussed in detail. This is followed by an analysis of the current state-of-the-art infrared bolometer technologies, the status of the infrared industry and the latest technology trends.

With good mechanical performance and mature fabrication technology of LIGA and UV-LIGA, Ni is chosen as the material of S style MEMS microspring. At 24°C and 25% relative humidity, five different points in LIGA Ni sample were tested with the MICRO HARDNESS TESTER, and the Young's modulus was 219GPa. From the tensile tests of UV-LIGA Ni sample the Young's modulus of UV-LIGA Ni is 180GPa. The S style microspring was fabricated by LIGA and UV-LIGA technology separately. Applying the Castigliano second theorem of energy method in macro theory, the spring constant formulas of S style microspring in three application modes were deduced, and the correctness was verified by the FEA (Finite Element Analysis) simulation. The experiments of S style microspring's deformation properties were carried out by the Tytron250 micro force test machine and a tensile measurement system separately. The experimental results agree with the theoretical analysis. Based on the above analysis, the change laws of microspring's spring coefficient in different application patters are summarized.

In this paper, a calibration method to improve the accuracy of MEMS Wire Bonder is presented. With the requirements of high accuracy and high speed in wire bonding, vision system has become one of important factors which influence the precision of MEMS packaging. It can be used as a feedback of control system to fulfill the requirement of accurate locating. A positioning system using computer vision technology has been designed to obtain high locating accuracy during wire bonding. The calibration of this system is the assurance to get distorting parameters and the relationship of all coordinate systems. Usually, Zhang's camera calibration method is widely used to get high accurate camera calibration results. But this method was only applied in normal imaging system. In this paper, the method is improved to be applied in micro-imaging system used for MEMS Wire Bonder. Combining the camera pinhole model and the Gauss lens law, the micro-imaging camera model is established. Certain smaller rotation angles are adopted to get acceptable calibration results. Simulations and experiments are performed to validate the proposed method with satisfied results.

MEMS fabrication technology has very high fabrication precision, but there is still fabrication error inevitably like any other fabrication technology. We adopt LIGA technology to fabricate a Micro Electro-Mechanical System. From the analysis of fabrication process, the fabrication errors of MEMS part consist of mask and LIGA fabrication error. The designed MEMS parts can be divided into metal and PMMA part. Synthesizing the mask and LIGA fabrication errors, the errors of metal entity and cavity structure are -10.5μm~+5.5μm and -5.5μm~+10.5μm. The errors of PMMA entity and cavity structure are -5μm~+10μm and -10μm~+5μm. Analyzing each situation, the most interference dimension of the four assembling situations is 20μm. According to the conclusion, we leave 10μm margin for each of the two parts assembling together. So the whole margin of the two parts is 20μm, which ensures that the two MEMS parts can be assembled reliably. Measuring the fabricated MEMS part with a micro precision measurement equipment indicated that the fabrication error was in the scope of theoretical analysis. The fabricated LIGA MEMS system can be assembled reliably and the centrifugal experiment indicated that the motional part worked well and moved to the destination position.

For higher-power-handling RF MEMS switches, the design of the switch is based on fixed-fixed beam capacitive structure with electrostatic actuation. Such RF MEMS switches are perceived to be unreliable because of the stiction and screening of the beam caused by charge accumulation in the dielectric layer. The research effort for a robust RF MEMS solution has been made for more than a decade. In this paper the models for stiction and screening caused by charge accumulation have been reviewed. As the first part of this paper, the possible charging mechanisms will be described, such as, 1) the dielectric charging arises from charges distributed throughout the dielectric material, 2) the presence of charges at the dielectric interface. In order to avoid the charge accumulation, trapped charges in the dielectric layer have to quickly vanish. Relaxing mechanisms of short time must be created inside of the dielectric for quick charge recombination. The second part of this paper will report the recent effort to create relaxing mechanisms of short time by using, such as doping dielectric, nano-composite dielectrics, or multi-layer stack of dielectric. Actuation wave form dependence of the charge accumulation will be also presented.

Phase shifter is one of the core components for phased-array antennas which find wide applications in satellite systems, telecommunications, wireless systems, radar systems and tracking systems. The current high-frequency phase shifters are mainly built upon active semiconductor technologies which suffer from high fabrication and assembly costs. In this work, we propose a cost-effective approach to fabricate distributed MEMS transmission line phase shifters on a polymer-glass substrate. The fabrication procedure is compatible with CMOS and post-CMOS processes. The polymerglass phase shifter was characterized from DC to 26 GHz. The measurements show a phase shift of 120° and a 2.5-dB insertion loss at 26 GHz.

Dielectric charging is one of the main problems leading to failure of capacitive RF MEMS switches. In this work phosphorus or boron ions were implanted into dielectric layer by ion implantation. After dielectric layer modification by ion implantation, we focus on investigation of the mechanisms of the charge accumulation and recombination after the sample electrically stressed with 80 V for 30 seconds. A Metal-Insulator-Semiconductor (MIS) capacitor structure is used for such an investigation. Silicon nitride films as the insulator in MIS structure were deposited by LPCVD process. The space charge accumulation in the silicon nitride film can be characterized by Capacitance-Voltage (C-V) measurement. Because of the ionization of the gas in the operating environment of the switch, ion injection by actuation voltage during the operation of the RF MEMS switch will play the role to enhance the charge accumulation in the dielectric layer. Our work offers a principle to understand the effect of the operating environment to the lifetime and reliability of the RF capacitive MEMS switches.

RF MEMS capacitive switches hold great promise in commercial, aerospace, and military applications. However, their commercialization is hindered by reliability concerns: charging effect in the dielectric layer can cause irreversible stiction of the actuating part of the switch. Presently, a popular method to investigate the charging/discharging in the dielectric layer is to measure an actual RF MEMS capacitive switch, which means a high experimental cost in fabricating MEMS switch devices. In this paper, a Metal-Insulator-Semiconductor (MIS) capacitor is used to investigate the charge accumulation in the dielectric layer of RF MEMS switches. By measuring the capacitance versus voltage (C-V) curves of MIS capacitor after voltage stressing, the dielectric charging/discharging characteristics are obtained. The experiment results indicate that the injected charges from the metal bridge in RF MEMS switches are responsible for stiction phenomena. In SiNx dielectric, the hole capture is more favored over electron capture, and the trapped charges tend to inhibit the charges further injecting. The effects of the actuation voltage waveform on the charge accumulation in the dielectric layer were investigated. It is verified that the tailored actuation voltage waveforms can be used to improve the reliability of RF MEMS capacitive switches.

Our recent research on the integrated micro biosensor systems was presented in this paper. Monolithic ISFET (ion-sensitive field-effect transistor) pH sensor and microelectrode amperometric immunosensor based on the micro/nano fabrication technology were studied. The Monolithic ISFET sensor, including the differential ISFET/REFET sensing device and the signal-processing circuit integrated on a single chip, was fabricated by standard CMOS and MEMS technology. Amperometric immunosensors were prepared based on MEMS technology with different microelectrode system and novel antibody immobilization methods. Both kinds of the sensors show attractive advantages, such as miniaturization, compatibility with CMOS techniques, easy to be designed into micro array and enables relatively rapid, reliable and inexpensive field-analysis.

A kind of photo-electronic integrated acceleration seismic detecting technology, which is novel and precise based on waveguide M-Z interference, is presented. It provieds modern geologic prospect with a novel detection technology. The principle of the photo-electronic integrated acceleration seismic geophone is introduced in this paper. The core of the photo-electronic integrated acceleration is the silicon harmonic oscillator, which is supported by four silicon beams and integrated on the signal beam of the M-Z interferometer. When the seismic mass is subjected to a normal acceleration a_z, the acceleration a_z, will result in an inertial force F_z, causing the mass to move up or down like the piston, until the counter force of the beam suspension equals this inertial force. The principle of the harmonic oscillator is briefly introduced, the factors influencing the anisotropic etching quality of the harmonic oscillator are analyzed in detail. In experiment, the fabrication technology was studied and improved. The high quality harmonic oscillator has been successfully fabricated. It has been applied in the integrated optical chip of "the theory and experiment research of photoelectric integrated acceleration seismic geophone technology".

An improved fabrication technique for silicon-based MEMS (MEMS: microelectromechanical systems) Infrared (IR) emitter is presented. The IR emitter was fabricated on silicon-on-insulator (SOI) wafer. The resistively heated polysilicon membrane fabricated by using deep reactive ion etching (DRIE) process on backside of SOI wafer has a low thermal mass structure, thus this IR-emitter can be modulated at high frequency. Additionally, the usage of the DRIE process instead of the wet etching process provides a more optimum design for the chip dimension. An appropriate boron (B) dope was used to realize the infrared absorption of silicon or infrared transparence of silicon for achieving self-heating or body emitting effect. By using the SOI wafer, the fabrication processes are simplified, and the production costs are decreased. The membrane temperature and emission spectrum of IR emitter were measured with thermal imaging system and spectroradiometer. The experimental results show that the IR emitter exhibits a strong emission in middle infrared range, and the modulation frequency can reach to 45Hz at 50% modulation depth. It is expected that this IR-emitter can be used in low cost sensing system.

Based on optic fiber beam sensor, a miniaturized laser induced fluorescence optical fiber detection system using solid-state laser (473nm) as excitation source is developed. The advantage of the LIF-D system are simple structure, small size, low cost, high sensitivity and high anti-disturbing. And the photon count method is used to improve the sensitivity of the detection. Using Sodium fluorescein as the test sample, distinct fluorescence signal with good repeatability is showed in the experiment. The concentration detection limit is up to 3×10^-13mol/L. the linear dynamic range is from 10^-6 to 10^-13 mol/L. It also shown that there was a nicer linear relation between the peak value of fluorescence signal to Sodium fluorescein concentration. Its relation coefficient is 0.99954. By changing detection cells this integrated detection system can be applied in micro flow analysis and for the normal biotechnology analysis of DNA.

A micro plane amperometric immunosensor for the detection of human immunoglobulin G is fabricated on silicon wafer based on Micro-Electro-Mechanical Systems (MEMS) technology. This microsensor is an electrochemical system composed of two-electrode (working electrode and counter electrode) integrated with a micro reaction cell made of SU-8 photoresist. The sensitive area of the working electrode is only 1 mm². A new method for the orientation-controlled immobilization of antibody based on staphylococcal protein A (SPA) and polypyrrole (PPy) is developed, which is fast, controllable and proper to microelectrode. PPy as a transition layer is first electropolymerized at the sensing area of the working electrode. Then SPA is co-electropolymerized with PPy for further orientedy immobilization of antibody. The electrodes modified by PPy and the coelectropolymer of PPy and SPA were characterized by SEM. HIgG range from 5 ng/ml to 640 ng/ml can be detected by this immunosensor with less consumption of reagent and acceptable reproducibility and stability.

A novel structure of optical fiber accelerometer based on MEMS torsional micro-mirror is introduced, including MEMS torsional micro-mirror and optical signal detection. The micro-mirror is a non-symmetric one, which means that the torsional bar supporting the micro-mirror is not located in the axis where the center of the micro-mirror locates. The optical signal detection is composed of PIN diode and dual fiber collimator, which is very sensitive to the coupling angle between the input fiber and output fiber. The detection principle is that acceleration is first transformed into torsional angle of the micro-mirror, then, optical insertion loss of the dual fiber collimator caused by the angle can be received by PIN. So under the flow of acceleration to torsional angle to optical signal attenuation to optical power detection, the acceleration is detected. The theory about sensing and optical signal detect of the device are discussed in this paper. The sensitive structure parameters and performance parameters are calculated by MATLAB. To simulate the static and modal analysis, the finite element analysis, ANSYS, is employed. Based on the above calculation, several optimization methods and the final structure parameters are given. The micro-mirror is completed by using silicon-glass bonding and deep reactive ion etching (DRIE). In the experiment, the acceleration is simulated by electrostatic force and the test results show that the static acceleration detection agrees with the theory analysis very well.

A novel pressure sensor with a mesa structure diaphragm based on microelectromechanical systems (MEMS) techniques is presented. The operating principle of the MEMS pressure sensor is expatiated by the Fabry-Parot (F-P) cavity model and the relation between pressure and interference light intensity is deduced in the sensor. The mechanical model of the mesa structure diaphragm is validated by simulation, which declares that the mesa structure diaphragm is superior to the planar one on the depth of parallelism. Experimental system is also introduced.

This paper focuses on the study of sensitivities of microcantilever chemical sensors based on SOI POLYMUMPS process. Through changing the geometry of beams and analyzing resonance frequency shift in a dynamic mode by using FEA (finite element analysis) method, the most sensitive structure, which is a triangle, is selected out from various kinds of beam designs. The relation between the sensitivity and the parameters such as length L, width W and thickness t is obtained by dynamic analyzing with the commercial software Intellisuite. This research provides the primary instruction for developing high sensitive multi-array biochips aiming at analyzing multiple parameters in parallel.

MEMS thermal transducers offer a promising technological platform for un-cooled IR imaging. We report on the fabrication and performance of an optical readout based MEMS IR FPA based on the bimaterial microcantilever. For the IR images of objects obtained by these FPAs, processed by the fast Curvelet transform denoising and inpainting algorithm, the image quality is improved obviously. Great compute and analysis have been realized by using the discussed algorithm to the simulated data. The experimental results demonstrate, better RMSE and highest Peak Signal-to-Noise Ratio (PSNR) compared with traditional methods can be obtained. At last we discuss the factors that determine the ultimate performance of the FPA. And we indicated that one of the unique advantages of the present approach is the scalability to larger imaging arrays.

An approach, which is used to fabricate diffractive optical elements (MOEs), is presented by applying reduction projecting system based on digital micro-mirror device (DMD). In this paper, coding-mask is combined with DMD which is real-time, flexible and easy for alignment. Pre-distortion according to the non-linear effect in the aerial image and resist course can be implemented. The accumulation of exposure energy can be obtained through modulating rotating velocity of mask graphics, and finally distribution of exposure, which is required, can be achieved. It shows that the method is practical and feasible on the grounds of the results of MATLAB simulation and experiments.

Electrochemical etching of patterned n-type silicon in hydrofluoric acid (HF) solution has been employed as a useful micromachining technique. In this paper, 4 um pitch regular wall array structures with high aspect ratio (larger than 20) were fabricated in n-typed silicon with back side illuminating. Differing from common hole array's fabrication, undesired formation of separated pores along the trench bottom becomes a serious problem in the wall array's fabrication. By adjusting the etching current density, we have successfully suppressed this phenomenon. A theoretical analysis of the formation mechanism of wall array will also be discussed in this paper.

A vibration-powered micro-power-generator has been presented in this paper, which has integrated two different energy harvesting mechanisms, e.g., Capacitive and Piezoelectric Mechanisms. The periodic vibration of the mass on movable electrode causes the variation of the capacitance, and the strain in the piezoelectric film. These two mechanisms can harvest the vibration energy and generate current in the output circuit. By using two different metals with large difference in working function as the two electrodes of the capacitor, our design, the combination of these two different scavenge mechanisms, can overcome the dependence of the traditional capacitive converter on the separate voltage source and improve the efficiency of power conversion. The volume of the designed device is less than 0.8 cm³. The simulated results reveal that this energy converter can provide an average output power of 82.21μW at an external vibration with a frequency of 111.4 Hz and amplitude of 0.2g.

In this paper, our work is focusing on investigating the mechanisms of the charge accumulation in dielectric layer of RF MEMS capacitive switches. In our experiments, silicon-nitride and silicon-oxide composite films, e.g., SiO₂+Si₃N₄ and SiO₂+Si₃N₄+SiO₂ films are chosen as the dielectric layers for study. The composite films were prepared by thermal oxidation and PECVD process. The Metal-Insulator-Semiconductor (MIS) structure was produced by using the composite films as the dielectric layer. The capacitance versus voltage (C-V) measurement is employed to study the space charge injection and relaxation process in the composite films. The results show that the charge accumulation can be reduced by using the composite films structure.

In this paper, a capacitive vibration-to-electrical energy harvester was designed. An integrated process flow for fabricating the designed capacitive harvester is presented. For overcoming the disadvantage of depending on external power source in capacitive energy harvester, two parallel electrodes with different work functions are used as the two electrodes of the capacitor to generate a build-in voltage for initially charging the capacitor. The device is a sandwich structure of silicon layer in two glass layers with area of about 1 cm². The silicon structure is fabricated by using silicon-on-insulator (SOI) wafer. The glass wafers are anodic bonded on to both sides of the SOI wafer to create a vacuum sealed package.

Bearing is a basic work-piece in machinery devices, and surface quality of steel ball is the main factor which affects the precision and longevity of bearing. Currently defects of steel ball are detected manually in industry. It is inefficiency and of high probability of misidentification. In order to assure the stability of steel ball quality this paper put forward an autodetection method based on vision technique to detect surface defects of steel ball. Firstly we designed an approach to fully expand the surface of steel ball according to the requirement of image detection. Then we made up a corresponding device to accomplish to designed approach and developed a platform system for image detection. Finally we carried a proving detection in some kind of defects of steel ball. The result of test shows that the method can be put into use to detect the general defects detection of steel ball.

An experiment system of maskless lithography has been presented using the characteristics of digital micro-mirror device (DMD) and principle of light refraction and diffraction. The experiment system contains a worked lamp-house, a DMD controlled by computer and an imaging system. The main parameter of devices, such as the incident and reflected light on DMD by selection of optimal optical devices and realizes process of exposure have been designed. In this paper, the particular characteristics of this system were described and some preliminary experimental results were discussed in finally. With this system, the realizable rate of reduction projecting is 14; the minimum precision is 1.3μm. It avoids the process of replacement mask and subsequent problems, and simplifies operation process, improves overlay accuracy, shortens production cycle of IC, and greatly decreases production cost. It is convenient to actualize the process of exposal and optional to replace the digital mask. These can provide possibility for maskless lithography being further improved.

The development of miniature, light-duty and low power consumption satellite-borne new concept devices based on MOEMS has significant meaning to realize forming inter-satellite network and minimizing, integrating, intellectualizing the payload of satellite-borne laser communication system. Agile beam steering control system based on MOEMS can realize the large FOV, high precision, agile response trace and optical axis alignment for multiple targets in spatial optoelectronic system. Comparing to traditional technology, agile beam steering control system lower the volumes, reduce the weight and power. In this article, ANSYS thermal analysis software is used to simulate the thermal distortion of the micro-mirrors on the MOEMS. ZEMAX optical analysis software is used to simulate the outgoing beam before and after the distortion of the mirrors. Under certain conditions, high power laser beam will have thermal effect on the reflector based on the reflective MOEMS APT precise steering device. The simulation results show that: the thermal distortion of the micro-mirror is tiny when radiated by low power laser, the influence can be neglected. However, when the laser power increasing, the receiving power decreased, the system performance degraded. In order to mitigate the negative influence, relevant method must be adopted.

The microscanning technique can improve a detector's capabilities in infrared focal plane array imaging. A common way to realize the microscanning technique is to utilize an actuator to make a reflector swing. Here a novel microscanning device is presented in this paper. The principle is on the condition that a spring subassembly matches the actuator, a reflector swings with high frequency. There are two methods of realizing the novel device. One is that the output of the spring subassembly is set as a variable parameter, so the spring subassembly and other elements make up of a spring system. Controlling the frequency and amplitude of the spring subassembly can realize the microscanning function. The other one is that the output of the spring subassembly is set as an invariable parameter, controlling the rotary acceleration of the reflector can realize the microscanning function. The different controllable modes of the two methods are established. In the two methods, controllable parameters are the rigidity coefficient of the spring, the advance compressing distance of the spring, the distance between the axis of the actuator and the rotary axis of the reflector, the rotary inertia of rotary units. The experiments show that the two methods all can realize the novel device, and the second method is better than the first one.

Two-axis optoelectronic tracking equipments generally use such mode that azimuth and pitch system are independently controlled. It leads to the two structures completely uncoupled, and reduces the state space dimension. But the main problem is that the rotational inertia of azimuth is much larger than that of pitch, which leads its dynamic tracking performance is worse. So to find a more suitable mechanics and more effective control strategy is necessary. Considering the tracking ability, this paper designs BMC (bandwidth mutual compensation) to uniformly correct the error of both the azimuth and pitch system in real time, it is realized by cross coupling control to the azimuth and pitch. The simulation result verified that compared with classical uncoupling system BMS not only guarantees the state space dimension but improves systematic tracking performance about 2" therefore, it is an effective control mode to the two-axis photoelectric tracking equipments.

This paper presents the design, fabrication and testing of a fiber optic switch actuated electromagnetically. The ferromagnetic gel coated optical fiber is actuated using external electromagnetic fields. The ferromagnetic gel consists of ferromagnetic powders dispersed in epoxy. The fabrication utilizes a simple cost-effective coating setup. A direct fiberto-fiber alignment eliminates the need for complementary optical parts and the displacement of fiber switches the laser coupling. The magnetic characteristics of magnetized ferromagnetic materials are performed using alternating gradient magnetometer and the magnetic hysteresis curves are measured for different ferromagnetic materials including iron, cobalt, and nickel. Optical fiber switches with various fiber lengths are actuated and their static and dynamic responses for the same volume of ferromagnetic gel are summarized. The highest displacement is 1.345 mm with an input current of 260mA. In this paper, the performance of fiber switches with various coating materials is presented.

This paper discusses modeling, design, fabrication and characterization of an optical scanner based on cantilever-type electrostatic zipping actuators. The electrostatic actuator has been designed to achieve high displacements for large optical scanning angles at lower actuation voltages. The zipping actuators are fabricated using multi-layer polysilicon foundry fabrication processes. The electrostatic force between the cantilever and the bottom electrode on the substrate pulls the cantilever down. With a warped cantilever, the force closes the gap from the anchored end and gradually the zipping effect actuates the entire cantilever. In our design, mechanical structures are arranged to avoid electrical shortcircuit. With various annealing temperatures, the warped angles are controllable. The cantilever serves as a reflective surface and the high out-of-plane displacement is used to steer a reflected laser beam for imaging and scanning applications. In this paper we present the design considerations in electrostatic zipping actuator displacement and control as well as the arrangement for optical scanning.

In the paper, a fast initial alignment of strapdown MIMU used in the two-dimension trajectory correction fuze was analyzed. According to the situation that MIMU can't work normally because of high shock on shrapnel of Compound Extended Range by Base Bleed and Rocket at firing, the MIMU in initial alignment with Bar-Itzhack and Berman's error model is presented and the observability was analyzed. It shows that the observability of MIMU on stationary base is poor. The selection of unobservable states was discussed. A Kalman filter estimation algorithm was provided, but the azimuth error converges very slowly in initial alignment. A fast estimation method of the azimuth error was proposed. It reveals that the azimuth error can be entirely estimated from the estimates of leveling error and leveling error rate without gyro output signal. It shows that the method can realize the rapid initial alignment of MIMU.

Micrometric displacement sensor with optical fiber was employed to inspect deformation of membrane box with air pressure changing, in order to avoid the defects in inspecting deformation, or improve and optimize performances of the sensors. A multi-path optical fiber sensor was utilized to measure the displacement, so that sensitivity is increased, and a little changing in air pressure may be measured. The relation between optical fiber sensor output changes and atmospheric pressure changes was standardized with a standard air pressure gauge. A setup for measuring atmospheric pressure was formed, the experiment results indicate that measurement range is 500-1060hpa, resolution is 0.2hpa, and accuracy is ±0.2hPa.