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An interesting characteristic of designing a n-fold multimode interference (MMI) optical splitter is obtained by BPM simulations. The length of the n-fold MMI region is approximately proportional to 1/λn if the refractive index profile of the MMI region is the same.
As the specific optical fiber, the tapered fiber has a number of applications. The diameter is the important parameter in problem study. The thesis discusses a new method to measure diameter of the tapered fiber, study the theory that measure the optical fiber radius with this method, and the numerical simulation is performed based on this.
This paper proposes a face detection algorithm combined skin color detection and improved AdaBoost algorithm. First, skin regions are segmented from the detected image, and candidate face regions are obtained in terms of the statistical characteristics of human face; Then focusing on the phenomena of overfitting in training process of classical AdaBoost algorithm, this paper proposes a novel method...
The paper introduces laser weld technology that rose in 1970's, outlines current technology development and its basic principles, advantages and disadvantages. The paper describes development of laser weld, weld process automation testing and a variety of advanced laser weld technology through introduction of laser weld in detail in specific areas such as automobile industry, aviation, shipbuilding,...
The purpose of this paper is to classify 93# and 97# gasoline by using principal component analysis (PCA) with self-organizing competitive neural network method and to establish near infrared transmission spectroscopy and reflectance spectroscopy qualitative identification model in 1100-1700nm spectral region. The spectral data is condensed by PCA method before modeling, and three principal components...
D-shaped optical fiber microwire (OFM) devices are investigated theoretically. They can be fabricated by wrapping the OFM on a removable rod or substrate. Optical wave guiding properties of these devices are discussed with numerical simulations. Dispersion properties of OFMs with different radius are studied as well. A grating based D-shaped OFM is proposed for sensing applications. The corresponding...
The rate and power evolution equations of erbium/cerium co-doped telluride fiber amplifier are proposed, solved numerically and compared with experiment data in literatures. With pump power of 130mW and fiber length of 12 cm, the internal gain of almost 30.0dB may be achieved in the amplifier.
Principle of polarization encoding based on electro-optic effect of LiNbO3 crystal is analyzed, influence on polarization encoding optical field effects is studied when the incident light polarization direction changes. Theoretical calculations show that, with the angle between the polarization of incident laser beam and the main axis of LiNbO3 crystal increases, rotation angle of polarization ellipse...
A novel type of GaN substrate for light emitting devices with a highly polarized output using metal-dielectric composite subwavelength grating structure is proposed. Characteristics of both optical transmission and polarization extinction ratio of the polarized GaN-based LED with a double-layer grating structures are investigated. It is found that both TM transmission (TTM) and the extinction ratio(ER)...
The cross-sensitive function of fiber Bragg grating (FBG) is deduced and analyzed theoretically in detail from the perspective of its physical mechanism when the FBG is affected by temperature and transverse pressure. Meanwhile, examples of different external physical factors and fiber parameters are considered for illustration purposes. Furthermore, with the numerical simulation, some valuable suggestions...
In this paper, we demonstrated two kinds of variable photonic devices: microlens and phase modulator. Both of them work based on the principle of dielectric-force-induced surface deformation. For each device, we depict its structure as well as the device fabrication processes. Their performances were tested and evaluated using optical microscope. Based on our investigation, such a deformable liquid...
The outstanding character of this technology is that it can detect both lossless and lossing events. The SOP (state of polarization) was selected as the sensitive character in this system, theory and simulation and preliminary experimental results show that this method is practical and reliable with high accuracy and high sensitivity and high resolution.
Using the magnetron sputtering technology, high quality Al2O3-based textured ZnO thin films (Al2O3/ZnO) which can be applied to solar cells' light trapping effect were fabricated by controlling the preparation parameters properly. X-ray diffraction (XRD) and Scanning electron microscopy (SEM) results show that O2 /(Ar+O2) flow ratio has great influence on Al2O3/ZnO films surface morphology during...
The imaging performance is a main factor for consideration in the acousto-optic tunable filter (AOTF) design. In this letter, on the basis of an accurate noncollinear acousto-optic interaction relationship, a design of the dispersion compensation for a noncollinear AOTF is developed. And the factors that influence the dispersion compensation are analyzed. The design is significant to improve the imaging...
A Dark-Pulse Brillouin Optical Time Domain Analyzer (BOTDA) configuration has been proposed to prolong the total sensing length by measuring both Brillouin Gain and Loss effect along fiber. The detected Brillouin signal will be identified by subtracting the two sided band of the Optical Carrier Suppressed (OCS) Stokes light. Due to the innovated configuration, the distributed Brillouin sensor developed...
Diffractive optical elements (DOE) have the special property of minus dispersion which can be used in the optical system instead of lens to improve its performance, lighten its weight, and reduce its volume effectively. Based on a conventional refractive long-length objective, a lightweight Hybrid Diffractive - Refractive (HDR) long-length objective was designed with the CODE V software. The optical...
A digital color 3.2-Mpixel CMOS imager has been realized in a standard 0.18um CMOS technology. This chip has integrated with a proposed high dynamic range programmable gain amplifier using the nonlinear function to satisfy the human eye response. For reducing the noise level before analog-to-digital converter, a low noise 2-shared 2.25T pinned photodiode active pixel and a correlated double sample...
Sub-pixel detection of target points is the performance bottleneck in camera calibration. Traditional algorithms are computational expensive or low precision when we do camera calibration in sport video analysis. In this paper, we propose a new algorithm to detect the grid-like target (i.e. tennis court in TV broadcasting). It has 3 parts: (1) color histogram based interested point classifier making...
The differential readout method for Super-Resolution Near-field Structure (Super-RENS) optical disc is analyzed with scalar diffraction theory. Base on the simple model of Super-RENS disks, we analyze the relationship between differential readout signal and several influence factors, such as the waist size of incident laser beam, the gap between data layer and super resolution(SR) layer, and nonlinear...
This paper presents a novel control approach based on digital image processing for elevator door protection system. This system is a non-contact type of elevator door protection system, which incorporates the background difference method and inter-frame difference method to achieve moving object detection and identifies the human body by the ratio of the image area and domain of variation. Finally,...
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