A comparative study on determination of optimum detection threshold for minimum BER in a WDM receiver with component crosstalk
01 Dec 2013-pp 1-4
TL;DR: In this article, the influence of signal-crosstalk beat noise on the performance of a preamplified WDM receiver is investigated assuming both Gaussian and non-Gaussian model.
Abstract: Component crosstalk causes severe system performance degradation in an optical network. In this paper the influence of the component crosstalk originated from signal-crosstalk beat noise, on the performance of a preamplified WDM receiver is investigated assuming both Gaussian and non-Gaussian model. From the analysis it is evident that for the finite interfering channels the results obtained using non-Gaussian model varies significantly from Gaussian model in terms of BER and the optimum detection threshold for obtaining minimum BER, but as the number of interfering channels approaches large value the variations are minimized. Effects on BER and optimum detection thresholds for minimum bit error rates are compared, summarized and analyzed in both graphical and tabular form for the two different model.
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TL;DR: It is exhibited that optimum range of optical power and laser linewidth of the LO helps in improving the performance of the considered system.
Abstract:
Dual-polarization quadrature phase shift keying (DP-QPSK) modulation format is emerging as a main contender for 37.5 GHz frequency grid of WDM systems. However, the optical add drop multiplexers (OADMs) affect the performance of the system because of narrow channel spacing. The local oscillator (LO) is an important component of the digital coherent receiver. This paper analyzes the effects of LO parameter on the performance of the considered system. It is exhibited that optimum range of optical power and laser linewidth of the LO helps in improving the performance of the considered system.
2 citations
01 Jan 2017
TL;DR: In this paper, the propagation of light in optical fibers, linear as well as nonlinear impairments and the effects of dispersion & fiber nonlinearities on the system performance of crosstalk limited AONs are discussed.
Abstract: Over the last few decades, optical fiber has become the transmission medium of choice because it provides efficient high data rate transmission at low Bit Error Rate. The optical fiber has a potential capacity of terabits-per-second. Modern commercial transport systems are capable of operating at 10 Gb/s with experimental system clocking 40 Gb/s and 100 Gb/s performance. The present transport networks cannot sustain such a high data rate of terabits-per-second. The fiber dispersion, fiber nonlinearities and electronic switching used in present transport networks, are the main limiting factors. A new generation of optical networks known as ‘All-Optical-Networks (AONs)’ overcomes this limitation by switching data entirely optically using Optical Switches. However AONs are prone to phenomena known as ‘node crosstalk’. This chapter discusses the propagation of light in optical fibers, linear as well as nonlinear impairments and the effects of dispersion & fiber nonlinearities on the system performance of crosstalk limited AONs.
1 citations
01 Jul 2017
TL;DR: In this paper, the performance degradation in a WDM receiver system is analyzed in terms of power penalty considering the presence of multiple component crosstalk sources, and the effect of the variation of number of interfering channels and cros stalk level are studied for a fixed thermal noise and photocurrent setting of the receiver.
Abstract: In this work, the performance degradation in a Wavelength Division Multiplexing (WDM) receiver system is analyzed in terms of power penalty considering the presence of multiple component crosstalk sources. In conventional way, power penalty is calculated considering the presence of all crosstalk sources simultaneously (i.e. worst case) which is not reality in practice and leads to unrealistic estimation. Here a probabilistic approach is adopted which considers all possible probabilistic appearances of the interfering channels and their realistic impact while calculating Bit Error Rate (BER) and penalty. Power penalty considering the presence of signal-crosstalk beat noise is formulated and the effect of the variation of number of interfering channels and crosstalk level are studied for a fixed thermal noise and photocurrent setting of the receiver. In addition the obtained results are compared with the existing worst case analysis model.
Cites background from "A comparative study on determinatio..."
...Several literatures are reported which provides the mathematical calculation of BER in a WDM receiver with component crosstalk in presence of single and multiple interfering channels [1]-[10], considering the transmitted and interfering signals as OOK (on/off keying) modulated light....
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TL;DR: In this paper , a simulation of the capacity of a fiber optic transmission link using WDM (Wavelength Division Multiplexing) system is presented, where a model for modeling and simulation of a real optical transmission link is presented.
Abstract: The main aim of the paper is modeling and simulation of fiber optic transmission. It also deals with ways to increase the capacity of fiber optic transmission links by using WDM (Wavelength Division Multiplexing) system. The parameters of the fiber optic transmission link were measured on a real optical transmission links and a model for simulation was set up. A simulation of increasing the capacity of a fiber optic transmission link was made in two ways. The first one is to increase the transmission speeds of the individual channels of the WDM system, and the second one is to increase the number of WDM system channels with lower individual speeds. The simulation results showed that the second method provides better quality of WDM service. The additional experiment was done on an existing ITU T G.655 optical fiber intended for WDM systems whose parameters were measured. Bit error rate and Q parameter for WDM system of 4 and 16 channel was used to check quality of proposed solution.
References
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Book•
01 Jan 1965
TL;DR: This chapter discusses the concept of a Random Variable, the meaning of Probability, and the axioms of probability in terms of Markov Chains and Queueing Theory.
Abstract: Part 1 Probability and Random Variables 1 The Meaning of Probability 2 The Axioms of Probability 3 Repeated Trials 4 The Concept of a Random Variable 5 Functions of One Random Variable 6 Two Random Variables 7 Sequences of Random Variables 8 Statistics Part 2 Stochastic Processes 9 General Concepts 10 Random Walk and Other Applications 11 Spectral Representation 12 Spectral Estimation 13 Mean Square Estimation 14 Entropy 15 Markov Chains 16 Markov Processes and Queueing Theory
13,886 citations
TL;DR: In this article, the authors derived the bit-error probability for a lightwave communications system using an amplitude-shift-keying (ASK) pulse modulation format and employing optical amplifiers such that amplified spontaneous emission noise dominates all other noise sources.
Abstract: A description is given of a relatively simple derivation of the bit-error probability for a lightwave communications system using an amplitude-shift-keying (ASK) pulse modulation format and employing optical amplifiers such that amplified spontaneous emission noise dominates all other noise sources Mathematically, this noise is represented as a Fourier series expansion with Fourier coefficients that are assumed to be independent Gaussian random variables The bit-error probability is given in a closed analytical form that is derived by the approximate evaluation of several integrals appearing in the analysis The author uses the theory to derive the Gaussian approximation and finds that it overestimates the bit-error rate by one to two orders of magnitude >
359 citations
"A comparative study on determinatio..." refers methods in this paper
...Assuming a typical receiver diagram of a direct detection amplitude shift-keying (ASK) with the fixed decision threshold setting and setting the decision threshold variable (d) at the ideal threshold s I /2, with the help of conditional probabilities using Bayes’ theorem into the sum of the error probabilities for N interferers, [11]-[12] the corresponding bit error probability are calculated to be ( ) ( ) 1 2 1 0 2 1 1 0 = + = = s e s e e m P m P P (7) Now ( ) 0 0 = s e m P can be written as [8]...
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TL;DR: In this paper, it was shown that the most severe degradations due to interference between signal and crosstalk electric fields are far larger than those predicted from simple power-addition without field interference.
Abstract: We find both theoretically and experimentally that crosstalk due to small component imperfections in transparent lightwave networks will tend to generate large performance degradations. The most severe degradations, which arise from interference between signal and crosstalk electric fields, are far larger than those predicted from simple power-addition without field interference. Systems corrupted by crosstalk from a single source of optical-field leakage appear to require component crosstalk levels /spl epsiv//spl les/-20 dB, if conventional receivers are used. Since the degradations are believed to depend on N/spl radic//spl epsiv/, where N is the number of crosstalk generators, each producing a crosstalk power level of /spl epsiv/, the problem is expected to grow rapidly severe with network size. >
301 citations
"A comparative study on determinatio..." refers background in this paper
...the signal-crosstalk beat noise and another is the crosstalkcrosstalk beat noise resulting from the beating of the optical crosstalk with itself [4]....
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TL;DR: In this paper, a saddle point integration method for solving the resulting line integral of a particular moment generating function is adopted, and a closed-form approximation for the bit error probability is also provided, which is within 0.01 dB from the exact numerical results.
Abstract: A novel approach to analytically evaluate the bit error probability in optically preamplified direct-detection systems is presented, which can take into account the effects of pulse shaping, chirping, filtering at the transmitter and the receiver, both pre- and postdetection, chromatic dispersion, and ASE noise. The method is computationally very fast in that the saddle point integration method for solving the resulting line integral of a particular moment generating function is adopted. A closed-form approximation for the bit error probability is also provided, which is within 0.01 dB from the exact numerical results.
198 citations
TL;DR: In this article, various types of nonlinear effects based on first effect such as self phase modulation, cross-phase modulation, and four-wave mixing are discussed and a comparative study of these effects is presented.
Abstract: The nonlinear effects in optical fiber occur either due to intensity dependence of refractive index of the medium or due to inelastic-scattering phenomenon. This paper describes various types of nonlinear effects based on first effect such as self-phase modulation, cross-phase modulation and four-wave mixing. Their thresholds, managements and applications are also discussed; and comparative study of these effects is presented.
194 citations