Optical switch is one of key supporting technologies in all-optical-network (AON). And electrostatic MOEMS (Micro-Optical-Electro-Mechanical Systems) switch plays a very important role in all the researched switches, because of their excellent features, including low insertion, low crosstalk and scalability. But the packaging technology has been limiting the development of optical switch. In this paper, the authors study the laser beam propagating during the free space and select collimator, design the pedestal to packaging and address aspects of the insertion loss that are most important loss mechanisms for the 2D cross-connect switch.
Microstructure fiber is a new kind of optical fiber. An arrangement of air holes running along the full length of the fiber provides the confinement and guidance of light. The light is confined in the silica core along the fiber axis. This fiber has endlessly single mode, special dispersion characteristics and so on. Using a vectorial effective-index numerical method, we investigated the dispersion characteristics of a microstructure fiber with honeycomb cladding structures. The dispersion, dispersion slope, and Kappa parameter can be designed neatly by changing the air hole size and the separation of the holes in fiber cladding. We demonstrated the Microstructure fiber with large absolute value of normal dispersion and negative dispersion slope at the wavelength of 1550nm. Conventional communication non-shifted single-mode fibers and nonzero-dispersion shifted fibers (NZ-DSF) can be compensated efficiently using the microstructure fiber at the wavelength around 1550nm.
Air-guiding photonic bandgag (PBG) fibers are new kind fibers which are quite different from conventional correspondence ones. In this paper, we studied the light transmission properties and light wave modes of hexagonal air-guiding PBG fibers. The fiber core is 10μm diameter air hole, surrounded by a cladding of 71.5μm diameter. The outer-cladding of the fiber is about 185μm. The experimental results show that when the wavelength ranges from 1430 to 1600 nm, there is merely no attenuation. It means that in these new fibers, light wavelength ranges widely. In addition, light wave mode and fiber core are the same in symmetrical structure. The theoretical results coincide with experimental results exactly.
Since CVD diamond film possesses desirable properties, it has been widely investigated, and much research has been made in this field. In this experiment, we mainly studied the characteristics of field emission from the CVD diamond films. The motivation for the experiment is to gain some insight into a possible emission mechanism. The diamond films are grown using a hot filament chemical vapor deposition, basing on the diamond micro-grits on silicon substrates. And the diamond micro-grits are deposited on silicon substrates using electrophoresis coat method, through a solution of diamond micro-grits in ethyl alcohol. This study has revealed that emission can be obtained at fields as low as 1.8V/μm. And the field emission measurements were carried out at a pressure of 10-4Pa.
Arrays of micro-sized LEDs which can be used as microdisplays have been demonstrated in recent years. In order to reduce the input and output connections to the arrays, we employ a matrix addressable architecture, in which all the pixels in each row are connected by a common metal line on the top of the window layer (top electrode) or at the base of substrate(bottom electrode). Decreasing the size of electrodes makes for minimizing the size of device. The optic and electronic isolation and good ohmic contact are also helpful to obtain superior optical and electrical performance. We describe a procedure of fabrication of AlGaInP-based orange micro-LED by wet etching. The structure of devices is etched using both isotropic and anisotropic solvent. The pixel size is about 16um x 20um, and there are 1000 x 818 pixels in the light emitting chip whose diagonal is 1-in.
Optical interconnection is the key technique of high-speed optical information process and optical communication. A lot of approaches for optical interconnection have been proposed since Goodman in Stanford University firstly proposed the optical interconnection for very large scale integrated circuits technology. A dynamical addressing device for optical interconnection was designed and fabricated in this paper. This optical device is based on one-dimensional nonlinear photonic crystal made on the planar waveguide. The nonlinear materials ZnS and ZnSe, which have large nonlinear refractive index coefficients, were alternately deposited on the waveguide to form one-dimensional photonic crystal. The Bragg condition is changed when the input power of the control light increased due to the nonlinear characters of the materials, thus the reflective angle of the signal light can be changed with the input power change of the control light. In our experiment, when increasing the power density of control light from 0 to 2.60X105W/cm2, the angle of the signal beam can be changed about 2o. The interconnection characteristics were investigated in theory and in experiment. The testing data agree well with theoretical predictions. This kind of devices is promising to use in the all-optical interconnection, optical information processing and optical communication
Bragg grating has lots of use in many optical field. Especially, in dense wavelength division multiplexing system and optical filters, and so on. Holographic Bragg grating with 1800 line/mm is fabricated in this experiment. Performances of holographic Bragg gratings are measured in our lab. Results show that this holographic Bragg grating can resolve 0.26nm fine line spectrum. Diffraction efficiency of Bragg grating can get 76% in 1.55 μm wavelength. Results also show that this kind of holographic Bragg grating may use in DWDM device and can produce fine narrow width spectra.
Photonic crystals have been widely studied in the fields of physics, material science and optical information technology. In general, the standard rectangular finite difference time domain (FDTD) method is used to predict the performances of photonic crystals. It is however very time consuming and inefficient. The current authors developed a software called GCFE, which is based on a non-orthogonal FDTD method. The software can be used to predict the photonic band structures, photonic states density and transmission and/or reflection coefficients for one-dimensional to three-dimensional photonic crystals. In the present paper, the derivations of the discrete Maxwell’s equations in time-domain and space-domain and the derivation of the discrete transfer matrix in real-space domain are briefly described firstly. In addition, the design idea and the functions of GCFE version 2.0.00 are introduced. Moreover, the band structures, transmission and reflection coefficients and photonic states density for the photonic crystal with cube lattice are calculated by our GCFE software, and numerical application results are also shown.
We study insertion losses of optical switch when the laser beam is propagating during the free space between two single mode fibers (SMFs) and the related assemblage challenges; Then a new packaging structure is developed for the hybrid-integration of free-space MOEMS (micro-opto-electro-mechanical systems) chip with a silicon micromachined submount to improve alignment accuracy. The submount is designed to accommodate various free-space MOEMS chips with minimal active optical alignment, thus reducing the packaging cost. The silicon submount has a central recess to place the MOEMS chip in, sixteen V-grooves for optical fibers, and micropits for micro ball lenses, all bulk micromachined at the same time by a single anisotropic wet etching step. A corner compensation technique is employed to prevent erosion of the convex corners, where different geometries meet. Through this assembling method, the fiber, micro ball lens can be aligned preciously thus reduced lateral and angular misalignment between them. Then total insertion losses can be decreased.
A theoretical method of focusing X-rays by the compound X-ray refractive lens is presented in this paper. The authors report their resent theoretical results including the material selection and structure parameters for such a device. As an example, a compound X-ray refractive lens with PMMA material is designed. The detailed fabrication process of the PMMA compound lens by LIGA technology is described. Moreover, some measured results by means of SEM are also shown. The structure height of one of the PMMA compound lens is measured to be 500μm.
In the present paper, a mask structure called adhering mask for excimer laser ablation is introduced. This mask is fabricated directly on the etched material, so it needn't a supporting chip and it thus has high transmission. Its absorber is made of gold and is fabricated by UV LIGA technology. Therefore the mask has more accurate structure and more smooth edges. This mask can fulfill the direct etching of the polymers by using a simpler optical system and can be a method of the mass production to some extent. The other mask is developed for X-ray lithography. It is made by UV LIGA process too. It consists of the substrate, the absorber and the supporter. The substrate is made of PI and the absorber is prepared by gold. The structure, fabrication process and experiment results of this mask are given.
Diamond maybe is an ideal electron emission material for field emission display because of its low work function and better chemistry stability. In this research, complex diamond conduct ceramic thin film is fabricated by using Ag- Bi-Pb-B-O base in organic conduct paste and diamond grains. The research aim is to find a method for making large area diamond-base electron emission material. Field emission performances of complex diamond ceramic are studied, too. The turn-on voltage and maximum stable emission current of material are 300 V and 760 (mu) A, respectively. The material also shows better emission stability at low vacuum pressure. The emitting center view is employed to explain the electron emission from diamond ceramic thin film.
We have studied the field emission characteristics of diamond films. The diamond films were deposited on mirror- polished silicon substrates by bias enhanced nucleation microwave plasma chemical vapor deposition technique. The nucleation density and surface morphological properties were analyzed by means of SEM. The field emission characteristics of diamond films nucleated on different bias conditions were studied by measuring emission current versus voltage curves (I-V plots). The diamond film has small grain sizes and high nucleation density when bias value is high, it has low turn- on voltage. The diamond film nucleated on higher methane concentration has also low turn-on voltage and its emission current increases rapidly as voltage increases.
The field emission was obtained from hydrogen plasma treated diamond films. It is found that the emission increased and is not stable after hydrogen treatment. Atomic force microscopy study shows that the surface morphology of the diamond films were changed after hydrogen treatment, but the effective work function is not reduced. These results were discussed.
In this research, we applied the physical and chemical characteristics of porous polysilicon to field emission. Porous polysilicon field emitter was fabricated by anodized, oxide, et al technology. Au film about 10 mm thickness as grid was used in device. Electron's emission property of device was measured in ultrahigh vacuum chamber. Also, the oxide time as effect factor to emission property was studied.
We had fabricated the internal field emission cold cathode of diamond thin film and researched its emission property. Diamond film was growth by microwave CVD technology. Insulator layer was porous oxide aluminum. Grid is Au thin film about 10 nm thickness. Results after measurement show that device had better internal field emission property.
Excitonic stimulated emission in the ZnSe-ZnS multiple quantum wells grown by the metal- organic chemical vapor deposition on GaAs substrates has been studied at room temperature. On the basis of the absorption spectrum and photoluminescence spectra under different excitation intensities measured, the major origin for the excitonic stimulated emissions in the ZnSe-ZnS/GaAs at room temperature obtained here are attributed to the exciton-exciton interaction.