Search query: loop reflect mirror

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abstract: In this paper, the development of loop mirror multi wavelength Brillouin fiber laser utilizing semiconductor optical amplifier and fiber Bragg grating is successfully demonstrated. A multi wavelength BFL structure employs a single mode fiber that acts as the gain medium, while the fiber Bragg grating act to reflect the signals and semiconductor optical amplifier is used to amplify the signal are employed to produce multiple channels. The implementation of difference parameter for semiconductor optical amplifier driven current, Brillouin pump power, Brillouin pump wavelength and length of single mode fiber, plays an important role in producing the multiple channels. The highest number of channels which is 15 achieved once 9 km of SMF length, semiconductor optical amplifier current at 800mA and low Brillouin pump power at 12 dBm are utilized in the laser structure. Furthermore, the implementation of semiconductor optical amplifier and reflectivity of fiber Bragg grating in Brillouin fiber laser structure gives a better performance in producing the multiple channels.
author_names: N A Idris

Nor Azura Malini Ahmad Hambali

Mohamad Halim Abd Wahid

Nurul Assikin Ariffin

Mukhzeer Mohamad Shahimin

M A M Azidin
title: Loop Mirror Multi wavelength Brillouin Fiber Laser Utilizing Semiconductor Optical Amplifier and Fiber Bragg Grating
year: 2017

abstract: We use a fibre loop mirror to reflect the residual pump power (RPP) into the fibre for solving the problems of the RPP in Raman amplifiers. The experimental results show that the novel bi directional pumping scheme without adding extra pump lasers is effective, and higher gain and lower noise are obtained for both the distributed and the discrete Raman amplifiers.
author_names: Chi Rong-Hua

Lu Kecheng

Yun Peng

Li Yi-gang

Dong Xiao-yi

Chen Wen-Zhao

Yang Guang-Ming

Li Zhao-bing
title: Performance Improvement of Distributed and Discrete Raman Amplifiers with a Fibre Loop Mirror
year: 2003

abstract: We use a fibre loop mirror to reflect the residual pump power (RPP) into the fibre for solving the problems of the RPP in Raman amplifiers. The experimental results show that the novel hi directional pumping scheme without adding extra pump lasers is effective, and higher gain and lower noise are obtained for both the distributed and the discrete Raman amplifiers.
title: Performance Improvement of Distributed and Discrete Raman Amplifiers with a Fibre Loop Mirror
year: 2003

abstract: We experimentally demonstrate a micro Sagnac loop beat wave interferometer by twisting a micro tapered fiber with a diameter of the wavelength scale. The polarization dependent coupling for the guided lights occurs at the interknitted region repeatedly while the loop serves as a mirror to reflect the guided lights. A longer interaction length of the interknitted region can lead to a narrower free spectral range. The high order modes can be excited under a tightly twisted condition and the wavelength beating phenomenon can be more explicitly obtained after the multi cycle coupling.
author_names: Nan-Kuang Chen

G J Cheng

Zhao-ying Chen
title: Micro Sagnac Loop Beat Wave Interferometer Based on High Order Modes Coupling in Tightly Twisted Micro Fiber Tapers
venue: IEEE Photonics Technology Letters
year: 2013

abstract: We demonstrate an efficient double pass L band erbium doped fiber amplifier (EDFA) incorporating chirped fiber Bragg grating (CFBG) The amplifier structure exploits the characteristics of CFBG to reflect the amplified signal back into the gain medium, filter out the recycled forward amplified spontaneous emission and block the residual 1480 nm pump power. The amplifier configuration has high gain and low noise figures as compared to double pass EDFA using broadband mirror. The demonstrated amplifier has gain of more than 48 dB and low noise figure of less than 4 dB at low input signal power of 40 dBm.
author_names: M Haleem

Mohammed Hayder Al-Mansoori

M Z Jamaludin

Fairuz Abdullah

Norashidah Md Din
title: High gain double pass L band EDFA with dispersion compensation as feedback loop
year: 2011

abstract: Fermi's theory of the motion of charged particles in a magnetic mirror has existed for several decades, often being cited and used in further studies in the field. The theory builds on the ability of astronomical bodies in space to generate a converging magnetic field, which simultaneously increases in strength. A particle colliding with such a field will either pass through or reflect back, depeding on the angle of attack i.e. from which direction it approaches the mirror. The theory also covers how particles can enter a loop between two such magnetic mirrors, bouncing back and forth. If these mirrors are advancing towards each other each collision slightly increasing the energy of the particle. This theorized phenomenon is also used to explain the observed exponential correlation between energy level and frequency of particle impacts on earth. This study examines the path of a particle when colliding with a simulized, generalized, magnetic mirror. It shows the path the particle takes during the reflection or while passing through. While past research exists on this topic, it has been done on mathematically proving the reflection effect. This study provides a novel model for showing the exact path of the particle up until, and even after the actual reflection, by providing a working computer simulation model. The model is both extendable and scalable for future researchon phenomena related to reflection, as well as for more complex simulations.
author_names: Eyvind Niklasson
title: Modeling the Path of a Charged Particle in a Magnetic Mirror
year: 2012

abstract: Most embed control system is working on the coordinates measurement and trajectory to track an object in the space need to a particular type of controller include specific algorithm. In this paper we explore designing optoelectronic system for intelligent and exact controlling of laser beam path depend on position sensor detector(PSD) in This paper presents a precise control system using a new and modern algorithm with a closed loop system to determine the ideal position of the laser beam path for measuring process, laser source is stable and fixed. We need to used mirrors to reflect ray to the laser beam path. It rotating by hybrid stepper motors. Field Oriented Control (FOC) method is presented to demonstrate effectiveness. For real time embedded controller. The system itself defines the situation and angle of each mirror. Series of experiments has been conducted to realize better transient response specifications.
author_names: Nihad Abdalla

Shi Liu

Ahmed Abdelrahim
title: Laser Beam Path Control Using a PSD Fuzzy Controller
venue: 2019 4th International Conference on Power and Renewable Energy (ICPRE)
year: 2019

abstract: Abstract This work establishes a computationally efficient model of temperature and diffusion dynamics in ball milled bimetallic Ni Al particulates. Mechanical contact conditions between adjacent bimetallic domains and temperature fields generated upon impact define the diffusive fluxes through the domains' interfaces. The concentration distributions are studied via Green's function methods, by defining mirror images which reflect the boundary diffusive resistance conditions. Predictions of the model are validated against experimental open loop scanning electron micrographs and X ray diffraction spectra at steady state. Dynamic models of diffusion saturation and internal temperature are developed for the design of closed loop controller via simulation. This feedback controller is implemented on a laboratory device, equipped with infrared thermometry for external vial temperature measurement, as a self tuning regulator. The controller adapts an efficiency parameter of the model that thus serves as a real time observer for internal temperature and diffusion saturation, which are physically inaccessible during processing. Experimental open loop results are employed to set thresholds of diffusion penetration to avoid early exothermic reaction during fabrication. By controlling the process duration, the regulation system successfully reproduces the material composition of the open loop reference tests, to ensure desired thermodynamic properties of the ball milled products and safety of the operation.
author_names: Matteo Aureli

Constantine C Doumanidis

I Emre Gunduz

Aseel Hussien

Yiliang Liao

Nikolaos Kostoglou

Claus Rebholz

Charalabos C Doumanidis
title: Bimetallic diffusion modeling and temperature regulation during ball milling
year: 2018

abstract: Methods for adjusting dither amplitude for MEMS mirrors in optical switches and optical switches employing such a method are disclosed. A dither amplitude of one or more MEMS mirrors may be adjusted in an optical switch having an input port, and an array of one or more MEMS mirrors that can be selectively optically coupled to one or more of N=3 optical input/output (I/O) ports. The MEMS mirrors are aligned mirrors to achieve nominal peak coupling at each of the N collimators. Digital to analog (DAC) settings for positioning mirrors in an open control loop as a function of the selected collimator are stored to a non volatile memory. The DAC settings are used to determine a dither amplitude DITHER(x) for one of the MEMS mirrors positioned to couple optical signals to an output port at a position x. The optical switch apparatus may comprise N=3 optical input/output (I/O) ports, an array of one or more MEMS mirrors that can selectively reflect one or more spectral channels to one or more of the N ports, and a servo control assembly in communication with said one or more of the MEMS mirrors. The servo control assembly includes memory containing digital to analog converter (DAC) settings for positioning each mirror in an open control loop as a function of a port position x. The servo control assembly is programmed to adjust dither amplitude of one or more of the MEMS mirrors using the stored DAC settings.
title: Method of automatic adjustment of dither amplitude of MEMS mirror arrays
year: 2006

abstract: This paper presents the development of a simplified and automatic heliostat positioning offset correction control system using artificial vision techniques and common CCD devices. The heliostats of a solar power plant reflect solar radiation onto a receiver (in this case, a volumetric receiver) placed at the top of a tower in order to provide a desired energy flux distribution correlated with the coolant flow (in this case air mass flow) through the receiver, usually in an open loop control configuration. There exist error sources that increase the complexity of the control system, some of which are systematic ones, mainly due to tolerances, wrong mirror facets alignment (optical errors) errors due to the approximations made when calculating the solar position, etc. that produce errors (offsets) in the heliostat orientation (aiming point) The approximation adopted in this paper is based on the use of a B/W CCD camera to correct these deviations in an automatic way imitating the same procedure followed by the operators. The obtained images are used to estimate the distance between the sunbeam centroid projected by the heliostats and a target placed on the tower, this distance thus is used for low accuracy offset correction purposes. Basic threshold based image processing techniques are used for automatic correction.
author_names: Manuel Berenguel

Francisco R Rubio

A Valverde

P Lara

Manuel Ruiz Arahal

Eduardo Fernandez Camacho

Marco A Lopez
title: An artificial vision based control system for automatic heliostat positioning offset correction in a central receiver solar power plant
year: 2004