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erbium-doped-fiber-amplifiers
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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
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