scholarly journals An Optimal Framework for WDM Systems Using Analytical Characterization of Refractive Index-Related Nonlinear Impairments

Electronics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 221 ◽  
Author(s):  
Muhammad Irfan ◽  
Farman Ali ◽  
Fazal Muhammad ◽  
Abdullah S. Alwadie ◽  
Adam Glowacz ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Networks ◽  
Wavelength Division Multiplexing ◽  
System Capacity ◽  
Limiting Factor ◽  
Transmission Range ◽  
Dispersion Parameters ◽  
Pass Filter ◽  
Low Pass Filter ◽  
The Impact

Nonlinear effects in the optical transmission systems (OTSs) are considered as the major performance limiting factor to provide high transmission rates over ultra-long distances. As the demands for system capacity, transmission range and the number of users is increasing exponentially with the development of mobile broadband, new challenges are being faced by the backbone optical networks. Mainly, the refractive index related non-linearities (RIrNLs) need to be characterized to design an optimal OTS for error-free transmission with provision of wavelength division multiplexing (WDM) to support for multiple channels. This paper provides an estimation technique of RIrNLs for long-haul transmission and their treatment for different channel spacing and the number of channels in a WDM system operating frequency domain multiple in multiple out (FD-MIMO) equalizer based digital signal processing (DSP) receiver and microstrip Chebyshev low pass filter. The main focus of this work is to utilize the existing structure of OTS for RIrNLs treatment with a low cost solution. Thus, by varying the parameters of the third order dispersion parameters, group velocity dispersion parameters, phase modulation dispersion and nonlinear refractive index, the impact of RIrNLs is investigated in detail to enhance the transmission range and capacity of the current OTS. The proposed system is analyzed in terms of range of input power, fiber length and received power for OTS figure of merits including bit error rate (BER) and optical signal-to-noise ratio (OSNR). Using duo-binary modulation, the BER achieved in this work is <10−5 till 500 km range, for maximum number of 32 channels, with 100 Gbps aggregate data rate, which shows the feasibility and effectiveness of our proposed model.

scholarly journals Transmission Performance Analysis of WDM Radio over Fiber Technology for Next Generation Long-Haul Optical Networks

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Badiaa Ait Ahmed ◽  
Otman Aghzout ◽  
Mounia Chakkour ◽  
Fahd Chaoui ◽  
Azzeddin Naghar
Keyword(s):  
Optical Networks ◽  
Wavelength Division Multiplexing ◽  
Impact Analysis ◽  
Transmission System ◽  
Radio Over Fiber ◽  
Signal Loss ◽  
Good Reliability ◽  
Differential Phase Shift ◽  
Fiber Technology ◽  
The Impact

This paper presents a detailed study of N-channels Wavelength Division Multiplexing (WDM) Optical transmission system using Radio over Fiber (RoF) technology. The study was applied to optical long-haul networks to overcome the nonlinearity effects, chromatic dispersion, and signal loss. For this purpose, Fiber Bragg Grating (FBG) has been implemented in 4-channels, 8-channels, and 16 channels WDM transmission system network at 10 Gb/s to compensate the dispersion and the nonlinear distortion. The use of erbium-doped fiber amplifiers (EDFA) has been also investigated to improve the quality of the transmission system. In Digital RoF, the impact analysis of modulation types such as Differential Phase-Shift Keying (DPSK) and Quadrature Amplitude Modulation (QAM) is also introduced. Constellation diagrams, received optical power, types of modulation, fiber dispersion, channel spacing variation, and laser power were considered to validate the study with the existing studies. All results achieve good reliability performance and prove the efficiency of the presented model.

To Mitigate the Effect of Cross-Phase Modulation by Employing PC-DCF Technique in Multi-Tone RoF System

2018 ◽  
Vol 0 (0) ◽  
Author(s):  
Namita Kathpal ◽  
Amit Kumar Garg
Keyword(s):  
Optical Networks ◽  
Wavelength Division Multiplexing ◽  
Phase Modulation ◽  
Performance Metrics ◽  
Signal To Noise Ratio ◽  
Optical Signal ◽  
Input Power ◽  
System Capacity ◽  
Bit Rate ◽  
Cross Phase Modulation

AbstractIt is known that the high bandwidth demands are accomplished by deploying the concept of wavelength division multiplexing in optical networks which involves the transmission of multiple wavelength signals spaced very close to each other. Due to closely spaced wavelengths, the signal power of one channel phase modulates the adjacent channel which in turn produces nonlinear effects such as cross-phase modulation (XPM), self-phase modulation (SPM) and four-wave mixing (FWM). Thus, in this paper, PC-DCF (pre-compensating dispersion compensating fiber) technique has been demonstrated and evaluated in the transmission link to compensate the XPM effects, and this result seems to significantly enhance w.r.t. transmission performance and system capacity considering performance metrics such as Optical Signal to Noise Ratio (OSNR), bit rate, Q-factor and bit error rate (BER). It is evident from the simulation results as well as through mathematical modeling that the proposed technique (PC-DCF) provides optimum results at the channel spacing of 100 GHz, bit rate of 10 Gbps and input power of 5 mW which collectively provides a 5 dB increase in OSNR as compared to the existing compensating technique.

scholarly journals Impact of the Incremental Analysis Updates on a Real-Time System of the North Atlantic Ocean

2008 ◽  
Vol 25 (11) ◽  
pp. 2055-2073 ◽  
Author(s):  
M. Benkiran ◽  
E. Greiner
Keyword(s):  
Real Time ◽  
North Atlantic ◽  
Weather Forecasting ◽  
Incremental Analysis ◽  
Real Time System ◽  
Pass Filter ◽  
Low Pass Filter ◽  
The North ◽  
The North Atlantic ◽  
The Impact

Abstract Incremental analysis updates (IAUs) are a procedure by which analysis increments can be incorporated into a model hindcast and forecast in a smooth manner. It is similar to nudging but has a better response, particularly in regions of missing data. The IAU procedure was popular in the late 1990s in weather forecasting centers, because it acts as a low-pass filter. The impact of the IAU is examined in the context of a real-time, eddy-permitting ocean forecasting system in the North Atlantic from Mercator Océan. Forecast scores and ocean physics are compared for the following three companion runs: a forced mode, a sequential analysis, and IAU. These comparisons confirm that the IAU is beneficial because it removes spinup effects such as spurious waves and tropical convective cells. Forecast scores are also slightly improved. In addition, contrary to the weather forecasting case where the model and data are fairly unbiased, the IAU has the advantage of correcting the systematic biases in the ocean data assimilation system.

An Improved Harmonic Current Detection Method Based on Variable Forgetting Factor RLS Algorithm

2013 ◽  
Vol 291-294 ◽  
pp. 2459-2463
Author(s):  
Minh Guang Vu ◽  
Wei Han ◽  
Da Zhi Wang ◽  
Yun Lu Li
Keyword(s):  
Dynamic Process ◽  
Detection Algorithm ◽  
Recursive Least Squares ◽  
Forgetting Factor ◽  
Harmonic Current ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Variable Forgetting Factor ◽  
The Impact ◽  
Current Detection

The effects of compensating and restraining the power system harmonics using active power filter are determined by the detection precision and its dynamic response characters. To improve both of them, a harmonic current detection algorithm based on variable forgetting factor Recursive Least-Squares algorithm is presented. The occurrence of the dynamic process is identified firstly by the judgment condition which is given by the algorithm, and then the forgetting factor is assigned dynamically, so that the convergent speed is significantly improved. The algorithm overcomes the impact of low-pass filter of traditional p-q or ip-iq algorithm, and releases the contradiction cased by the conflicting requirements of forgetting factor value between steady process and dynamic process. So it has better dynamic performance. Simulation and experiments prove the validity and feasibility of the approaches.

Comparative Simulation of Thermal Noise Effects for Photodetectors on Performance of Long-Haul DWDM Optical Networks

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
I. S. Amiri ◽  
Fatma Mohammed Aref Mahmoud Houssien ◽  
Ahmed Nabih Zaki Rashed ◽  
Abd El-Naser A. Mohammed
Keyword(s):  
Optical Networks ◽  
Wavelength Division Multiplexing ◽  
Thermal Noise ◽  
Signal To Noise Ratio ◽  
Avalanche Photodiode ◽  
Input Power ◽  
Superior Performance ◽  
Noise Effects ◽  
Wavelength Division ◽  
The Impact

AbstractLong-haul 16-channel dense-wavelength division multiplexing networks employing two different avalanche photodiode (APD) structures (Si and InGaAs) and positive-intrinsic-negative (PIN) photodetectors are simulated and compared under thermal noise effects for different fiber lengths. The effect of thermal noise level on the transmission quality with a variation of amplifying section length, number of amplifying sections and channel speed is discussed. The impact of thermal noise on the system performance is analyzed by varying input power from −5dBm to 20dBm for both 25 km and 50 km amplifying section at 100 km fiber length. The performance is evaluated for both 5 Gb/s and 10 Gb/s data rates over transmission distances up to 500 km. A comprehensive comparison is developed based on signal-to-noise ratio (SNR), quality factor (Q-factor) and bit error rate (BER). It is found that both APD structures achieve superior performance up to distance of 350 km comparing to PIN photodetectors for 50 km amplifying section. The system provides optimum performance at input power Pin = 10dBm in case of 50 km amplifying section, but then afterwards, the performance is degraded rapidly due to nonlinearities. The results revealed that the worst performance scenario is at 10–18 W/Hz thermal noise in terms of higher BER and lower Q-factor. Finally, the desirable BER of 10–12 is achieved at Q-factor of 6.78 and SNR of 23 dB.

scholarly journals PERFORMANCE ANALYSIS OF WSXC AND WIXC SSM OXC IN WDM OPTICAL NETWORKS

2014 ◽  
pp. 7-11
Author(s):  
MD. ISHTIAQUE AZIZ ZAHED ◽  
MD. SHAH AFRAN
Keyword(s):  
Optical Networks ◽  
Wavelength Division Multiplexing ◽  
Wavelength Conversion ◽  
Optical Network ◽  
Propagation Delay ◽  
Optical Signal ◽  
Wdm Optical Networks ◽  
Power Penalty ◽  
Time Duration ◽  
The Impact

The impact of inband crosstalk on an optical signal passing through optical cross-connect nodes (OXC’s) in wavelength division multiplexing (WDM) optical network, is studied from the equation of electric field with crosstalk and the corresponding current. The analysis has been done for two SSM (space switching matrix) OXC architecture namely WSXC & WIXC where later one has full wavelength conversion capability. Although WIXC attenuates more crosstalk though it is found that depending on the values of optical propagation delay differences, coherent time of lasers and time duration of one bit of the signal, the required power penalty in WIXC may be greater than that of WSXC in some cases. The analysis has been performed on the measures of Bit Error Rate (BER) and Power Penalty.

scholarly journals Searching for Chaos Evidence in Eye Movement Signals

Entropy ◽  
2018 ◽  
Vol 20 (1) ◽  
pp. 32 ◽  
Author(s):  
◽  
Keyword(s):  
Time Series ◽  
Fractal Dimension ◽  
Eye Movements ◽  
Noise Reduction ◽  
Eye Movement ◽  
Eye Tracker ◽  
Dynamic Features ◽  
Pass Filter ◽  
Low Pass Filter ◽  
The Impact

Most naturally-occurring physical phenomena are examples of nonlinear dynamic systems, the functioning of which attracts many researchers seeking to unveil their nature. The research presented in this paper is aimed at exploring eye movement dynamic features in terms of the existence of chaotic nature. Nonlinear time series analysis methods were used for this purpose. Two time series features were studied: fractal dimension and entropy, by utilising the embedding theory. The methods were applied to the data collected during the experiment with “jumping point” stimulus. Eye movements were registered by means of the Jazz-novo eye tracker. One thousand three hundred and ninety two (1392) time series were defined, based on the horizontal velocity of eye movements registered during imposed, prolonged fixations. In order to conduct detailed analysis of the signal and identify differences contributing to the observed patterns of behaviour in time scale, fractal dimension and entropy were evaluated in various time series intervals. The influence of the noise contained in the data and the impact of the utilized filter on the obtained results were also studied. The low pass filter was used for the purpose of noise reduction with a 50 Hz cut-off frequency, estimated by means of the Fourier transform and all concerned methods were applied to time series before and after noise reduction. These studies provided some premises, which allow perceiving eye movements as observed chaotic data: characteristic of a space-time separation plot, low and non-integer time series dimension, and the time series entropy characteristic for chaotic systems.

Measurement Method of Equivalent Water Level for Nuclear Steam Generator Based on Data Fusion

2017 ◽  
Author(s):  
Xianling Li ◽  
Zhiwu Ke ◽  
Mo Tao
Keyword(s):  
Data Fusion ◽  
Water Level ◽  
Steam Generator ◽  
Pid Controller ◽  
Measurement Method ◽  
Feed Water ◽  
Level Control ◽  
Pass Filter ◽  
Low Pass Filter ◽  
The Impact

The nuclear U-tube steam generator (UTSG) is a key component for nuclear power plant, and the water level of UTSG must maintain a desired value. In order to overcome the impact of the false water level, an equivalent water level is proposed based on data fusion to simplify the water level control of UTSG. The equivalent water level is composed of steady and dynamic compositions, which are got through the water level sensor of UTSG and flow rate sensors for feed water and steam of UTSG respectively. The steady and dynamic compositions are generated by a low-pass filter and a high-pass filter according to the measuring data characteristics on frequency domain. The false water level characteristics of UTSG have been removed through the equivalent water level application, and then the impact of non-minimum phase characteristic of UTSG has been weakened remarkably. A simulation of water level control is conducted based on the equivalent water level, and the result indicates that a simple PID controller can make the UTSG run with a satisfied water level control performance. It is usually difficult to gain a satisfied control effect through a simple PID controller without equivalent water level, so the measurement method of equivalent water level will benefit the operation of UTSG by simplifying the control process obviously.

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