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fiber-amplifiers
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Gain spectrum of silica erbium-doped CROW amplifier
, Article Photonics North 2009, Laval, QC, 24 May 2009 through 27 May 2009 ; Volume 7386 , 2009 ; 0277786X (ISSN) ; 9780819476685 (ISBN) ; Bahrampour, A. R ; Quebec Photonic Network; Institut National d'Optique (INO); Canadian Photonics Consortium (CPC); Universite Laval, Centre for Optics, Photonics and Lasers; Ontario Photonics Industry Network (OPIN) ; Sharif University of Technology
2009
Abstract
An Erbium-doped silica CROW can be employed as a band pass and band stop amplifier in telecommunication systems. Also it can be proposed as wide band amplifier as well as narrow band amplifier. We investigate theoretically and simulate structure of Erbium-doped CROW (EDC) with different parameters to realize its performance and possible applications as an amplifier. In this paper we try to consider effect of different parameters on gain spectrum of systems. © 2009 SPIE
Gain ripple minimization in fiber Raman amplifiers based on variational method
, Article Optics Communications ; Volume 281, Issue 6 , 2008 , Pages 1545-1557 ; 00304018 (ISSN) ; Ghasempour, A ; Rahimi, L ; Sharif University of Technology
2008
Abstract
In this paper, the variational method is employed for minimizing the gain ripple of multi-wavelength fiber Raman amplifiers. The variance of gain spectrum of the fiber Raman amplifier is regarded as the cost function, restriction on total pump power and average gain is given as the constraints of the minimization problem. It is shown that the minimization problem with any necessary constraints on the pump powers, average gain and signal to noise ratio, is reduced to a two-point boundary value problem. The method gives the entire possible local and global solutions. The method is applied to different examples of fiber Raman amplifiers with different lengths from 25 km to 100 km and different...
Continuous-wave amplification in bismuth-oxide fiber optical parametric amplifiers
, Article 2011 IEEE Winter Topicals, WTM 2011, 10 January 2011 through 12 January 2011, Keystone, CO ; 2011 , Pages 161-162 ; 9781424484287 (ISBN) ; Jamshidifar, M ; Govan, D ; Marhic, M. E ; Sharif University of Technology
Abstract
We review our investigations on bismuth-oxide fiber as an amplifying medium for parametric amplifiers with continuous-wave pumping. The results lead to new applications in demultiplexing, which are discussed
Investigation of transient response of erbium-doped fiber lasers by semi-classical theory
, Article Journal of Optical Communications ; Volume 28, Issue 4 , 2007 , Pages 248-251 ; 01734911 (ISSN) ; Mahjoei, M ; Jamali, P ; Sharif University of Technology
Fachverlag Schiele und Sohn GmbH
2007
Abstract
The transient response of all optical gain clamped multi channel erbium doped fiber amplifiers (EDFA's) and optical fiber inverter is studied by a semi-classical model. Using the semi-classical theory, the electric field interacting with mater is considered classical and the medium is quantized according to the equations of motion for density matrix. The rate equations and "self consistency" equations, which yield amplitude and phase of the electric fields of oscillator and amplifying channels are derived by considering Maxwell's equations and equation of motion of density matrix. The governing equations form a system of coupled partial differential equations. The relaxation oscillation...
An inhomogeneous theoretical model for analysis of PbSe quantum-dot-doped fiber amplifier
, Article Optics Communications ; Volume 282, Issue 22 , 2009 , Pages 4449-4454 ; 00304018 (ISSN) ; Rooholamini, H ; Rahimi, L ; Askari, A. A ; Sharif University of Technology
2009
Abstract
Optical fiber doped with lead salts quantum dots (QDs) of different radii, has previously been proposed as a wide-band amplifier in the optical communication range. The emission and absorption spectra of QDs are size-dependent. Optical fiber amplifier doped with QDs of different sizes is an inhomogeneous gain medium. This inhomogeneity is the principle of operation of wide-band quantum-dot-doped fiber amplifiers (QDFAs). To study the effects of inhomogeneity such as spectral hole burning on the amplifier behavior, a fiber amplifier with an arbitrary size distribution of QDs is taken into consideration. The light propagation equations and rate equations for the inhomogeneous medium are...
Investigation of Optical Bistability in Quantum Dot and Erbium Doped Fiber Ring Resonator
, M.Sc. Thesis Sharif University of Technology ; Bahrampour, Alireza (Supervisor)
Abstract
Optical bistability is one of the most important results of nonlinear optics. The term optical bistability refers to the situation in which two different output intensities are possible for a given input intensity. Interest in optical bistability stems from its potential usefulness as a switch for use in optical communication and in optical computing. Optical bistability is resulted by nonlinear phenomena such as kerr effect, two photon absorption and saturable absorber. In this thesis, we study the optical bistability in a double-coupler ring resonator, in which the right half of ring is made of an erbium doped fiber amplifier for compensating the loss by the gain of EDFA, and the left half...
Optical bistability in fiber ring resonator containing an erbium doped fiber amplifier and quantum dot doped fiber saturable absorber
, Article Applied Optics ; Volume 51, Issue 29 , 2012 , Pages 7016-7024 ; 1559128X (ISSN) ; Farshemi, S. S ; Sajjad, B ; Shahshahani, F ; Bahrampour, A. R ; Sharif University of Technology
2012
Abstract
In this paper we study the optical bistability in a double coupler fiber ring resonator which consists of an erbium doped fiber amplifier (EDFA) in half part of the fiber ring and a quantum dot doped fiber (QDF) saturable absorber in the other half. The bistability is provided by the QDF section of the ring resonator. The EDFA is employed to reduce the switching power. The transmitted and reflected bistability characteristics are investigated. It is shown that the switching power for this new bistable device is less than 10 mW
The moment method for fiber raman amplifier gain ripple minimization
, Article Optics Communications ; Volume 281, Issue 14 , 2008 , Pages 3673-3680 ; 00304018 (ISSN) ; Farman, F ; Ghasempour, A ; Sharif University of Technology
2008
Abstract
We aim to propose a novel fiber Raman amplifier modeling based on the moment method, which is previously introduced for modeling the inhomogeneous Erbium doped fiber amplifiers and recently employed to analyze the fiber Raman amplifier with continuous pump spectrum. In this model, the number of governing equations is independent of the number of signals and according to the degree of accuracy it is proportional to the number of pumps. This method is employed to analyze the Raman fiber amplifiers with an arbitrary input signal line shape and to minimize the gain ripple of the fiber Raman amplifier with respect to the pump powers and pump frequencies. © 2008 Elsevier B.V. All rights reserved
A moment method for analysis the gain spectrum in fiber Raman amplifier with broadband pumps
, Article Optics Communications ; Volume 281, Issue 4 , 2008 , Pages 587-591 ; 00304018 (ISSN) ; Teimourpour, M. H ; Rahimi, L ; Sharif University of Technology
2008
Abstract
The governing equations of optical fiber Raman amplifier with broadband pumps in the steady state are systems of uncountable nonlinear ordinary differential equations (NODE). In this paper, the Moment method is used to reduce the uncountable system of NODE to a system of finite number of NODE. This system of equations is solved numerically. The results are compared with that of the full numerical method. It was shown that the Moment method is a precise and efficient technique for analysis of optical fiber Raman amplifier with broadband pumps. © 2007 Elsevier B.V. All rights reserved
An inhomogeneous theory for the analysis of an all-optical gain-stabilized multichannel erbium-doped fiber amplifier in the presence of ion pairs
, Article Optical Fiber Technology ; Volume 14, Issue 1D , 2008 , Pages 54-62 ; 10685200 (ISSN) ; Keyvaninia, S ; Karvar, M ; Sharif University of Technology
Academic Press Inc
2008
Abstract
In this paper the gain dynamics of an all-optical gain-clamped multichannel erbium-doped fiber amplifier (EDFA) with an inhomogeneous active medium in the presence of ion pairs is modeled. A two-level model for single ions and a three-level model for ion pairs are used to drive the propagation and rate equations of inhomogeneous laser medium. The governing equations are an uncountable system of partial differential equations (PDEs). Using the moment method, the system of PDEs is converted to a finite system of ordinary differential equations (ODEs). The solution of the system of ODEs is used to analyze the gain dynamics of all-optical gain-stabilized multi-wavelength heavy doped EDFA....
Terahertz Generation from a Laser Source, Using Modulation Instability
, M.Sc. Thesis Sharif University of Technology ; Kavehvash, Zahra (Supervisor) ; Rostami, Ali (Co-Supervisor)
Abstract
A novel broadband and tunable terahertz (THz) source based on the modulation instability phenomenon (MI) is proposed. By introducing higher-order dispersion terms in nonlinear Schrodinger equation (NLSE) the MI gain is spread toward larger frequencies which in turn shifts the input optical frequency to the THz range. In this method, the need for any further pump signal is eliminated while the input power is reasonable, less than 1W, due to using EDFA fiber. By changing the input signal power, the generated THz signal frequency could be tuned. The proposed structure is numerically simulated in the designed values of dispersion orders
Power evolution along phase-sensitive parametric amplifiers: An experimental survey
, Article Optics Letters ; Vol. 39, issue. 21 , Nov , 2014 , p. 6114-6117 ; Vedadi, A ; Shoaie, M. A ; Soto, M. A ; Denisov, A ; Mehrany, K ; Thevenaz, L ; Bres, C. -S ; Sharif University of Technology
Abstract
We propose and experimentally demonstrate a method based on Brillouin optical time-domain analysis to measure the longitudinal signal power distribution along phase-sensitive fiber-optical parametric amplifiers (PS-FOPAs). Experimental results show that the amplification of a PS-FOPA could go through different longitudinal profiles and yet finish with the same overall gain. This behavior is in sheer contrast with theoretical expectations, according to which longitudinal gain distribution should follow certain profiles determined by the initial relative phase difference but can never end up in the same overall gain. The gap between theory and experiment only becomes evident when the pump...