Current Issue : January - March Volume : 2017 Issue Number : 1 Articles : 7 Articles
In this paper human face machine identification is experienced using optical correlation techniques\nin spatial frequency domain. This approach is tested on ORL dataset of faces which includes\nface images of 40 subjects, each in 10 different positions. The examined optical setup relies on\noptical correlation based on developing optical Vanderlugt filters and its basics are described in\nthis article. With the limitation of face database of 40 persons, the recognition is examined successfully\nwith nearly 100% of accuracy in matching the input images with their respective Vanderlugt\nsynthesized filters. Software simulation is implemented by using MATLAB for face identification....
By analyzing the factors which affect the wall-plug efficiency of semiconductor Laser Diodes (LDs),\na high efficiency 1060 nm LD was designed, including active region, waveguide layers, and cladding\nlayers. The simulation result shows that the component of In in InGaAs in the active region\ncannot be too small, otherwise the thickness of InGaAs active layer will exceed the critical thickness,\nmeanwhile the asymmetric large optical cavity can decrease the cavity loss effectively. The\nepitaxial structure was grown by MOCVD, experimental results of varying cavity length showed\nthat the internal quantum efficiency reached 98.57%, and the cavity loss was only 0.273 cm1. Devices\nwith 4 mm-cavity-length and 100 m-strip-width were fabricated, 47.4% wall-plug efficiency\nwas reached under QCW pulse condition at room temperature, and the peak wavelength was\n1059.4 nm....
In this study, we fabricated a sapphire based fiber-optic radiation sensor. To evaluate the fiberoptic\nradiation sensor, we measured the spectrum and intensity of the luminescence generated\nfrom the fiber-optic radiation sensor according to the thickness of the PMMA block by irradiation\nof gamma rays emitted from a Co-60 source. And the result was compared with the value calculated\nfrom the formula of Lambert-Beer....
A detailed procedure is presented to compute analytically the acoustooptic coupling coefficient between copropagating core and\nlowest-order cladding modes in tapered fiber optics. Based on the effect of the local bending, the linear and nonlinear variations in\nthe refractive index aremodeled. A set of equations and parameters are presented in order to calculate the influence of acoustooptic\neffect in nonlinear pulse propagation.We will show that as the tapered fiber diameter decreases more energy can be transferred to\nthe cladding and the nonlinear phenomena can compensate the coupling coefficients effects....
A new design for an all optical flip flop is introduced. It is based on a nonlinear Distributed\nBragg Reflector (DBR) semiconductor laser structure. The device does not\nrequire a holding beam. An optical gain medium confined between 2 Bragg reflectors\nforms the device. One of the Bragg reflectors is detuned from the other by making its\naverage refractive index slightly higher, and it has a negative nonlinear coefficient\nthat is due to direct absorption at Urbach tail. At low light intensity in the structure,\nthe detuned Bragg reflector does not provide optical feedback to start a laser mode.\nAn optical pulse injected to the structure reduces the detuning of the nonlinear Bragg\nreflector and a laser mode builds up. The device is reset by detuning the second\nBragg reflector optically by an optical pulse that generates electron-hole pairs by direct\nabsorption. A mathematical model of the device is introduced. The model is\nsolved numerically in time domain using a general purpose graphics processing unit\n(GPGPU) to increase accuracy and to reduce the computation time. The switching\ndynamics of the device are in nanosecond time scale. The device could be used for all\noptical data packet switching/routing....
This paper proposes a novel way for controlling the generation of the dissipative bright soliton and dark soliton operation of lasers.\nWe observe the generation of dissipative bright and dark soliton in an all-normal dispersion fiber laser by employing the nonlinear\npolarization rotation (NPR) technique.Through adjusting the angle of the polarizer and analyzer, the mode-locked and non-modelocked\nregions can be obtained in different polarization directions.Numerical simulation shows that, in an appropriate pump power\nrange, the dissipative bright soliton and dark soliton can be generated simultaneously in the mode-locked and non-mode-locked\nregions, respectively. If the pump power exceeds the top limit of this range, only dissipative soliton will exist, whereas if it is below\nthe lower bound of this range, only dark soliton will exist....
An optical link, based on a conventional Scotch tape waveguide, for sensing applications\nrequiring rapid on-site assembly is proposed and demonstrated. The flexible waveguide contains\nan integrated aluminum one-dimensional grating coupler that, when stuck on the radiative surface\nof a light emitting device, allows light to be coupled in and transmitted through the tape, whose\ntip end is, in turn, adhered onto the photosensitive surface of a photodetector. The (de)coupling\napproaches exhibit high alignment tolerances that permit the formation of a free-standing flexible\noptical connection between surface-normal optoelectronic devices without the need of specialized\nequipment. As the first demonstration of a sensing application, the proposed optical link is easily\nconfigured as a cost-effective intensity-based refractometric sensor for liquid detection, which can be\napplicable to on-site quality and process control of, for example, beverages....
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