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Article
Publication date: 11 October 2011

Gurmeet Kaur, M.L. Singh and M.S. Patterh

Fiber nonlinearities are anticipated to impose transmission limitations due to the enhanced total interaction length in long‐haul dense wavelength division multiplexing…

Abstract

Purpose

Fiber nonlinearities are anticipated to impose transmission limitations due to the enhanced total interaction length in long‐haul dense wavelength division multiplexing (DWDM) optical transmission systems. The purpose of this paper is to analytically study the combined effect of stimulated Raman scattering (SRS) and four‐wave mixing (FWM) in the presence of amplified spontaneous emission (ASE) noise generated by erbium‐doped fiber amplifiers (EDFAs).

Design/methodology/approach

The paper presents analytical analysis of DWDM optical transmission systems in the presence of two significant fiber nonlinearities (SRS and FWM).

Findings

Simple expressions are derived to study the dependence of signal‐to‐noise ratio (SNR) on the amplifier spacing between two consecutive amplifiers.

Originality/value

The authors have analytically studied the combined effect of SRS and FWM in the presence of ASE noise generated by EDFAs. The novelty of the work is that it has considered all the three factors simultaneously and the expressions are derived for calculation of SNR.

Details

Journal of Engineering, Design and Technology, vol. 9 no. 3
Type: Research Article
ISSN: 1726-0531

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Article
Publication date: 10 December 2019

Ufuk Parali and Cahit Pinar

The purpose of this study is to develop new tandem configurations of erbium-doped fiber amplifier (EDFA) using all possible pump-signal-direction schemes in simulation to…

Abstract

Purpose

The purpose of this study is to develop new tandem configurations of erbium-doped fiber amplifier (EDFA) using all possible pump-signal-direction schemes in simulation to identify a system configuration with the best performance in the means of the highest gain with the lowest noise figure (NF) output.

Design/methodology/approach

The spatial evolution of the physical properties such as gain, NF, population density and amplified spontaneous emission along the total length of the double-stage single-pass EDFA and single-stage double-pass EDFA configurations under all possible pumping direction schemes was investigated. Giles and Desurvire method was used for the mathematical modeling of these configurations where the two level coupled system model equations was solved in MATLAB. In the simulation of the all proposed configurations, an input signal of −35 dBm at the wavelength of 1550 nm and a total of 14 mW pump power at the wavelength of 1480 nm was used for a consistent analysis.

Findings

The numerical value of the results obtained is specific to the input parameter values used in the simulations; however, configuration-wise, the EDFA systems found with the best performance are not parameter specific.

Originality/value

The results of this numerical work will help future experimental research of designing and developing ultra-efficient EDFA systems.

Details

Engineering Computations, vol. 37 no. 4
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 14 November 2008

S. Selleri and A. Cucinotta

The aim of this paper is to show the effectiveness of the finite element method (FEM) to study the properties of different kinds of photonic crystal fibers (PCFs)…

Abstract

Purpose

The aim of this paper is to show the effectiveness of the finite element method (FEM) to study the properties of different kinds of photonic crystal fibers (PCFs), presenting results which highlight the FEM flexibility, exploited according to the particular PCF feature under investigation.

Design/methodology/approach

The FEM has been applied to a new emerging class of optical fibers, the so‐called PCFs, also known as microstructured or holey fibers.

Findings

It has been shown how to design and customize the PCF cross‐section to achieve desired values of dispersion, confinement loss, nonlinear or amplification properties. Reported examples prove the FEM ability to deal with complex geometries, arbitrary refractive index steps and distribution, and to be integrated with other approaches for a better and accurate analysis of the considered fiber.

Research limitations/implications

Limitation in the FEM use can be given by the required computation effort in terms of memory occupancy and time, even if computational power of modern workstations can attenuate this aspect.

Practical implications

The FEM can be a very powerful tool to investigate and design actual structures to be used in several fields, as telecom, sensing, fiber lasers, spectroscopy.

Originality/value

The novelty of the paper is given by the exploitation of the FEM feature to design a new emerging class of optical fibers, considering all numerical aspects given by the unusual characteristics of the domain and problem under investigation.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 27 no. 6
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 11 May 2010

Fikri Serdar Gokhan and Gunes Yilmaz

The purpose of this paper is to demonstrate an effective and faster numerical solution for nonlinear‐coupled differential equations describing fiber amplifiers which have…

Abstract

Purpose

The purpose of this paper is to demonstrate an effective and faster numerical solution for nonlinear‐coupled differential equations describing fiber amplifiers which have no explicit solution. MATLAB boundary value problem (BVP) solver of bvp6c function is addressed for the solution.

Design/methodology/approach

Coding method with the bvp6c is introduced, signal evolution, threshold calculation method is introduced, gain and noise figure are plotted and superiority of the bvp6c solver is compared with the Newton‐Raphson method.

Findings

bvp6c function appears to be an effective tool for the solution fiber amplifier equations and can be used for different pump configurations of BFAs and RFAs. The excellent agreement between the proposed and reported results shows the reliability of the proposed threshold power calculation method.

Research limitations/implications

The paper eases the work of the fiber optic research community, who suffer from two point BVPs. Moreover, the stiffness of the signal evolution which is faced with high pump powers and/or long fiber lengths can be solved with continuation. This superiority of the solver can be used to overcome any stiff changes of the signals for the future studies.

Practical implications

The main outcome of this paper is the numerically calculation of the threshold values of fiber amplifiers without the necessity of the experiment. The robustness improvement of the solution is that the solver is able to solve the equations even with the poor guess values and the solution can be obtained without the necessity of analytical Jacobian matrix.

Originality/value

MATLAB bvp6c solver has proven to be effective for the numerical solution of nonlinear‐coupled intensity differential equations describing fiber amplifiers with two‐point boundary values. Beside the signal evolution, thresholds of Brillouin and Raman fiber amplifiers can also be calculated by using the proposed solver. This is a notable and promising improvement of the paper, at least from a fiber optic amplifier designer point of view.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 29 no. 3
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 30 March 2010

Gurmeet Kaur, M.L. Singh and M.S. Patterh

The current generation of light wave systems benefit from increased transmission distance by using optical amplification and increased capacity by using dense wavelength…

Abstract

Purpose

The current generation of light wave systems benefit from increased transmission distance by using optical amplification and increased capacity by using dense wavelength division multiplexing (DWDM) technology. The reach of present systems is limited by the noise contributed by the used amplifiers, combined with nonlinear effects from transmission. This paper aims to address these issues.

Design/methodology/approach

The nature and extent of degradations in the optical DWDM systems due to these limiting factors have been discussed in this paper.

Findings

It has been learnt that stimulated Raman scattering (SRS), four wave mixing (FWM) and amplified spontaneous emission (ASE) are the important factors in optical DWDM systems. These factors limit the system capacity of the transmission systems drastically.

Originality/value

It can be concluded from the discussion that while designing an efficient DWDM system, an optimization of the channel separation and the amplifier separation is required to minimize the nonlinear effects (FWM and SRS) along with the ASE noise introduced by inline optical amplifications.

Details

Journal of Engineering, Design and Technology, vol. 8 no. 1
Type: Research Article
ISSN: 1726-0531

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Article
Publication date: 8 March 2011

Fikri Serdar Gokhan and Gunes Yilmaz

The purpose of this paper is to demonstrate an effective and robust numerical solution for Raman fiber amplifier (RFA) equations which have no explicit solution. MATLAB…

Abstract

Purpose

The purpose of this paper is to demonstrate an effective and robust numerical solution for Raman fiber amplifier (RFA) equations which have no explicit solution. MATLAB BVP solvers are addressed for the solution.

Design/methodology/approach

The continuation method proposed for the solution of RFA equations using MATLAB BVP solvers is explained. Scripts for improving the power values at the boundaries with continuation, extending fiber length with continuation and calculation of the analytical partial derivatives using the MATLAB Symbolic toolbox are introduced. Comparisons among the different MATLAB BVP solvers have been made. Using the continuation method, signal evolutions for different kinds of RFA amplifier configurations are plotted.

Findings

The paper finds that MATLAB BVP solver with the continuation method can be used in the design of various kinds of RFAs for high powers/long gain fiber spans.

Research limitations/implications

The paper will assist the fiber optic research community who suffer from two or more point boundary‐value problems. Moreover, the stiffness of the signal evolution which is faced with high pump powers and/or long fiber lengths can be solved with continuation. This superiority of the solver can be used to overcome any stiff changes of the signals for future studies.

Practical implications

The increased research interests and practical demands for RFAs have been calling for reasonable and efficient means for the performance evaluation of RFAs before the real amplifiers are fabricated. The solution method presented in this paper will be an efficient means for the solution of this issue.

Originality/value

MATLAB BVP solvers have been proven to be effective for the numerical solution of RFAs with multiple pumps and signal waves. Using the continuation method, in a distributed RFA with ten pump sources, 2,400 mW total input pump power is achieved. The improvement of the total power is about 1.4 times compared with those of the previously reported methods. Using the MATLAB BVP solvers, total power/fiber span can be improved further using the continuation process with the cost of computational time. This is a notable and promising improvement from a RFA designer's point of view.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 30 no. 2
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 2 March 2012

Fikri Serdar Gokhan and Gunes Yilmaz

The aim of the paper is to demonstrate a fast numerical solution for Raman fiber amplifier equations using proposed guess functions and MATLAB intrinsic properties. MATLAB…

Abstract

Purpose

The aim of the paper is to demonstrate a fast numerical solution for Raman fiber amplifier equations using proposed guess functions and MATLAB intrinsic properties. MATLAB BVP solvers are addressed for the solution.

Design/methodology/approach

The guess functions proposed for the solution of RFA equations using MATLAB BVP solvers are derived from Taylor expansion of pump and signal wave near the boundary to specifically obtain convergence for the initial mesh point. The guess functions increase simulation speed significantly. In order to improve the simulation speed further, vectorization and analytical Jacobians are introduced. Comparisons among bvp4c and bvp5c have been made with respect to total pump power, number of signals, vectorization with/without analytical Jacobians, fiber length, relative tolerance and continuation method. The simulations are performed to determine the effect of the run time on the choice of the number of equally spaced mesh points (N) in the initial guess, and thus optimal N values are found.

Findings

MATLAB BVP solvers have been proven to be effective for the numerical solution of RFAs with the proposed guess functions. In particular, with vectorizing, run time reduction is between 2.1 and 5.4 times for bvp4c and between 1.6 and 2.1 times for bvp5c and in addition to vectorizing, with the introduction of the analytical Jacobians, the reduction is between 2.4 and 6.2 times for bvp4c and 1.7 and 2.2 times for bvp5c, respectively, depending on the total pump power between 1,000 mW and 2,000 mW and the number of signals. Also, simulation results show that the efficiency of the solution with proposed guess functions is improved more than six times compared with those of previously reported continuation methods. Results show that the proposed guess functions with the vectorization and analytical Jacobians can be used for the performance evaluation of RFAs for the high power systems/long gain fiber span.

Practical implications

The robust improvement of the solution proposed in this paper lies in the fact that the derived guess functions for the RFAs are highly effective in the sense that they assist the solver to converge to the solution for any total pump power value in a wide range from 1 to 3,000 mW and for any fiber lengths ranging 1 to 200 km which are used in practical applications. Hence, it is practicable for the performance evaluation of the existing RFA networks.

Originality/value

The novelty of this method is that, starting with the co‐propagating single pump and signal RFA schema, the authors derived the guess function specifically for the initial mesh points rather than using its analytical approximations. Moreover, the solution is generalized for co‐/counter propagating pumps/signals with the curve fitted coefficient(s).

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 31 no. 2
Type: Research Article
ISSN: 0332-1649

Keywords

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Article
Publication date: 1 April 2000

Jian‐Guo Zhang, A.B. Sharma, Yu‐De Ni and Zheng Li

The design issues on network architecture and modulation scheme that can be used to implement reliable MIL‐STD‐1773 avionics optical fiber data buses are discussed. Both…

Abstract

The design issues on network architecture and modulation scheme that can be used to implement reliable MIL‐STD‐1773 avionics optical fiber data buses are discussed. Both single‐star and multi‐star architectures are presented to such optical fiber data buses. Several network configurations based on passive and/or active coupling components are also considered, and they are compared in terms of system complexity and reliability. Moreover, three modulation schemes are presented, i.e. partial trilevel Manchester II bi‐phase coding, extended Manchester II bi‐phase coding with beginning‐stopping flags, and pseudo‐four‐ary pulse width modulation, respectively. Their use can feasibly solve the problem associated with fast identification of correct operation states of an active transmitter at the output of optical receivers.

Details

Aircraft Engineering and Aerospace Technology, vol. 72 no. 2
Type: Research Article
ISSN: 0002-2667

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Article
Publication date: 1 April 1993

L. Guan, C. Pusarla, G. Halkias and A. Christou

As speed and complexity of electronic systems increase, the interconnect density has become the critical limitation to the performance of electrical systems. The…

Abstract

As speed and complexity of electronic systems increase, the interconnect density has become the critical limitation to the performance of electrical systems. The performance of computing and switching systems can be increased by optimizing the interconnect density and throughput. At the board to board level, electrical interconnects at high speeds require a bulky and expensive backplane. At the chip to chip area, the allocation of interconnects limits the performance of the chips. Electrical lossy lines limit the maximum interconnect distance due to reflections, risetime degradation, increased delay, attenuation and cross talk . Optical interconnects present the possibility of solving the interconnect problems by potentially achieving a high bandwidth and high volume density of channels. At high data rates (greater than 1 Gb/s) several channels may operate with negligible mutual interference.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 12 no. 4
Type: Research Article
ISSN: 0332-1649

Content available
Article
Publication date: 1 September 2001

Abstract

Details

Sensor Review, vol. 21 no. 3
Type: Research Article
ISSN: 0260-2288

Keywords

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