Many low or middle level 3D reconstruction algorithms involve a robust estimation and selection step by which parameters of the best model are estimated and inliers fitting this model are selected. The RANSAC algorithm is the most widely used robust algorithm for this step. However, this robust algorithm is computationally demanding. A new version of RANSAC, called distributed RANSAC (D-RANSAC), is proposed in this paper to save computation time and improve accuracy. We compare our results with those of classical RANSAC and another state of the art version of it. Experiments show that D-RANSAC is superior to RANSAC in computational complexity and accuracy, and comparable with other proposed improved versions.
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.
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.
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.
A kind of new optical interconnection element -- holographic Bragg grating with a red sensitive photopolymer is reported in this paper. Grating-splitting boards with equal intensity are designed and fabricated on a red sensitive photopolymer by Lloyd's interferometer of the special design, and they are successfully demonstrated in application of optical butterfly interconnection network.
We report the fabrication of waveguides gratings coupler in photoresist by using a volume holographic gratings and that of the holographic gratings by Red Sensitive Photopolymer at 632.8 nm. The holographic gratings can produce diffracted light of 0 and -1 orders with equal intensity. The two diffracted light beams yield the interference fringe of period in near field, which is as laser sources to expose the photoresist on waveguide.
A scheme of holographic Bragg grating for achieving optical butterfly interconnection is presented in this paper. Its essential structure units are Bragg grating-slitting board of volume phase holography (splitting ratio 1:1). Photopolymer with red light is used as holographic recording medium of making gratings. The effect of the scheme has been demonstrated.
The nonlinear-optical properties of poly (p-phenylene- vinylene) (PPV) were studied. The sign and size of the real and imaginary part of (chi) (3) have been measured at 532 nm to be -5.168 multiplied by 10-9 esu and -1.952 multiplied by 10-9 esu, respectively by the Z-scan method. The nonlinear refractive index n2 is of -4.271 multiplied by 10-9 esu, and all-optical switching in the PPV thin-film waveguide was observed by prism coupling.
Fabrication and measurement of monolithic integrated waveguides with three parts, that is transmissive grating and two spheroidal geodesic lenses on Ag+ - Na+ ion exchanged glass substrate, is reported. The monolithic waveguides are measured using diode laser of 1.3 micrometers and the Bragg diffraction efficiency of grating of waveguides is 40%.
We fabricated a digitized dual-frequency coupling gratings. And it was demonstrated experimentally that a two level digitization of the analog profile performs the waveguide interference between two free space waves.
A chirped grating was fabricated on CdSxSe1-x doped glass waveguide characterized by intensity dependent refractive indices to use for all-optic tunable interconnection. The focal line move of 80000 nm was observed when the power density of the guided wave was changed. Five possible locations of the focal line for optical interconnection are determined.
The design principle, manufacture and technical parameters of optical fiber encoder with coded resin plate is reported in this paper. The resin plate has special superiority compared with glass plate. The resin plate can be adapted to use in vibrative environments (such as spaceflight and elevator and so on). The resin plate is lighter, so it has higher mechanical conversion efficiency. It can be made the super small size to be used in special space.
An optoelectronic interconnection based on volume holographic coupling elements located on a light-guiding glass plate has been realized by exposure at the wavelength of 630 nm. A light beam is reconstructed at the same wavelength and guided by total internal reflection inside the glass plate. The contraction coefficients and the refractive index change of the thin film of red sensitive photopolymer have been measured. Coupling gratings with an accurate period and a slanted angle have been designed.
The photopolymer with red light was used as holographic recording media for the first time. Two kinds of interconnection light guided-board, reflective type and transmissive type, were successfully fabricated. Holographic exposure interferometer of single light path was designed. The equations of grating period and grating fringe inclination were derived, respectively.
This paper reports the method and technology on the fabrication of grating coupler with double-corrugation on BK7 glass waveguide for operation at 780 nm wavelength. Twice ion beam etching has technologically made possible the fabrication of high-efficiency waveguide grating coupler.
This paper proposes new optical butterfly interconnection network constructions based on the butterfly signal-flow diagrams for performing 1D and 2D fast Walsh-Hadamard transforms. We build the optical butterfly interconnection network hardware systems by using the binary phase diffraction gratings and masks. The systems are simple, regular in constructions, and easily implemented by means of gratings and masks. They relate directly optical processing with mathematical calculation, and are conveniently controlled and adjusted. These important characteristics have been verified by computer simulation.