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Article
33% RZ-DPSK 10 Gb/s WDM Transmission

Authors: Rasha Hassan Abbas --- Ali Y. Fattah
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2011 Volume: 29 Issue: 11 Pages: 2282-2297
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

200 GHz-spaced 16-channel 40Gbit/s WDM signal transmission is proposed in Cband using 33% return-to-zero differential-phase-shift-keying (RZ-DPSK) format over a 5 spans of dispersion shifted-Anomalous fiber link. A parametric run on each span fiber length is performed (from 25 km up to 100 km). The performance of 16 40 Gb/s 33% RZ-DPSK WDM channels is analyzed using the “Optical Simulation “software. While, the nonlinearity results related to optical fiber system have been simulated. Results that are given in this work are obtained using MATLAB R2009b (version 7.9.0.529).

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Article
Spectral Efficiency Improvement of the Optical Communication Systems

Authors: Aqeel R. Farhan --- Dr. Ali Y. Fattah
Journal: IRAQI JOURNAL OF COMPUTERS,COMMUNICATION AND CONTROL & SYSTEMS ENGINEERING المجلة العراقية لهندسة الحاسبات والاتصالات والسيطرة والنظم ISSN: 18119212 Year: 2014 Volume: 14 Issue: 1 Pages: 44-57
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

Abstract –In this paper, different amplitude and phase modulation formats are investigated and compared to find the optimum one among them for high spectral efficiency (SE) Wavelength Division Multiplexing (WDM) systems with an acceptable value of the Bit Error Rate (BER). Also, the effectiveness of using the polarization interleaving scheme in minimizing the nonlinear effects in the optical fiber channel for the various modulation formats is investigated. (Optisystem v 7.0) A simulation package is used to simulate the system. The simulation results show the effectiveness of using the polarization interleaving in decreasing the nonlinear effects. RZ modulation formats are found to give a better BER value than the corresponding NRZ formats but with a smaller value of the SE. Among the compared modulation formats, RZ-AMI and the RZ-DQPSK are the only formats that are found to give the optimal performance for high capacity WDM networks.


Article
Mitigation of Fiber Nonlinearity Effects in Ultra High-Dense WDM System by Using Fractional Fourier Transform for 32 Channel System
تقليل التأثيرات اللاخطية في منظومات التقسيم المتعدد للطول الموجي العالية الكثافة بأستخدام تحويل فورير الجزئي لنظام ذو 32 قناة

Authors: Ali Y. Fattah --- Saif Hussam Abdul-Wahed
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2016 Volume: 34 Issue: 1 Part (A) Engineering Pages: 50-60
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

The optical signal is severely degraded when transmitted in the fiber due to both the linearand nonlinear distortions. It is well known that, the linear distortions in single mode fiberinclude chromatic dispersion (CD) and polarization-mode dispersion (PMD) while self-phasemodulation (SPM), cross phase modulation (XPM) and four-wave mixing (FWM) areconsidered the most among nonlinear distortions. A method called Fractional Fourier Transform(FRFT) has been applied to mitigate fiber nonlinearity impairments. In this work, 10 Gb/soptical fiber system with five spans, each of length 60 km, for three types of modulation formats(Return-to-Zero Differential Phase Shift Keying (RZ-DPSK), Return-to-Zero DifferentialQuaternary Phase Shift Keying (RZ-DQPSK) and Carrier-Suppressed Return-to-Zero (CSRZ)),single and multi-channel transmission systems are designed and simulated using “OptiSystem(2011) version 10.0” software package. The BER of thirty two channel systems (channel No.16)at bit rate 10 Gb/s per channel, 300 km link length of CSRZ modulation format with channelspacing of 50 GHz at SNR 10 dB without FRFT is 10-4.6 and 10-6.4 with FRFT. The BER ofthirty two channel system (channel No.16) at bit rate 10 Gb/s per channel, 300 km link length ofCSRZ modulation format with channel spacing of 25 GHz at SNR 10 dB without FRFT is 10-2.56 and 10-3.24 with FRFT.

الاشاره الضوئية تتدھور بشده عندما ترسل في ليف ضوئي وذلك نتيجة للتشوھات الخطيه وغير الخطية. كماو تشتت حالة الاستقطاب (chromatic dispersion) ھو متعارف علية, التشوھات الخطية تتظمن التشتت اللونيالتظمين ,(self-phase modulation) بينما التظمين الطوري الذاتي (polarization-mode dispersion)تعتبر من (four-wave mixing) و الخلط الموجي الرباعي (cross phase modulation) الطوري الصليبيFractional Fourier ) اقوى التشوھات غير الخطية. تم استخدام طريقة مقترحة تدعى تحويل فورييه الجزئيتم تطبيقھا لتقليل شوائب الليف غير الخطية. لقد تم في ھذه الاطروحه اعتماد نظام ضوئي بسرعه (Transformتناقل بيانات 10 كيكابت/ثانية مع خمسه دورات كل دوره طولھا 60 كم لثلاثه انواع من التضمين (التضمينوالتضمين من نوع ,RZ-DQPSK التضمين الطوري الرباعي التفاضلي ,RZ_DPSK الطوري التفاضليوقد تم اعتماد نظام القناه المفرده ونظام القنوات المتعدده بأستخدام حزمه المحاكاة ألبصريه , (CSRZلنظام ذو اثنان وثلاثين قناة (القناة السادسه عشر) بسرعه (BER) نسبه خطأ الرقم الثنائي . (optisystem v. 10)التباعد بين القنوات 50 , SCRZ تناقل بيانات 10 كيكابت/ثانية, 300 كم طول خط النقل, بستخدام التضمين نوع4,6 بدون تحويل فورير - كيكا ھرتز عند قيمه نسبه قدره الاشاره الى قدره الضوضاء مقدارھا 10 ديسيبل كانت 1لنظام ذو اثنان وثلاثين قناة (القناة (BER) 6,4 بوجود تحويل فورير الجزئي. نسبه خطأ الرقم الثنائي - الجزئي و 10, SCRZ السادسه عشر) بسرعه تناقل بيانات 10 كيكابت/ثانية, 300 كم طول خط النقل, بستخدام التضمين نوع- التباعد بين القنوات 25 كيكا ھرتز عند قيمه نسبه قدره الاشاره الى قدره الضوضاء مقدارھا 10 ديسيبل كانت 103,24 بوجود تحويل فورير الجزئي.


Article
Generation and Transmission of Optical Solitons in Ultrahigh Speed Long-Haul Systems

Authors: Ali Y. Fattah --- Noor Q. Flaih
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2016 Volume: 34 Issue: 7 Part (A) Engineering Pages: 1427-1438
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

High bit rates optical communication systems pose the challenge of their tolerance to linear and nonlinear fiber impairments.The techniques processing of linear and nonlinear impairments involve which balance between linear and nonlinear impairments. Optical Solitons are the special breed of wave packets which can propagate over long distance without changing in their shape and velocity. Effective transmission distance could be increased by proper circuit designing and balancing Group velocity dispersion (GVD) with its counterpart Self phase modulation (SPM. The comparison between the results of single channel soliton source and CW laser 33% RZ_DPSK modulatiom formats shows that the soliton source has the better performance than the CW. Soliton source which has a Q factor of 98.4 at distance of 60Km,while the CW laser with 33% RZ-DPSK has 70.01 at distance at 60Km, when power lunch is (10) dBm. On other hand the BER is (-11.2) when SNR (5) dB at 60km, while CW laser with 33% RZ-DPSK has BER (-20) at SNR (5) dB at distance 60Km.The soliton system at multichannel (8x40Gb/s) with 50 GHz channel spacing has BER (-15) while 33%RZ-DPSK has BER (-9) at SNR (6.87) dB at 60Km distance.

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Article
Smallest Of-Order Statistic-CFAR Analysis in Weibull Clutter
تحليل مرتب الخواص - الأصغر من - لمعدل الإنذار الخطأ الثابت بجلبة ويبل

Authors: Salih M.Salih --- Ali Y. Fattah --- Bayan M. Sabbar
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2005 Volume: 24 Issue: 7 Pages: 923-937
Publisher: University of Technology الجامعة التكنولوجية

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Article
Electronic Signal Processing for Cancelation of Optical Systems Impairments

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Abstract –In this paper 40 Gb/s DP-QPSK system with coherent reception and DSPunit for optical fiber impairments compensation is proposed . The DSP unit processesthe detected coherent DP-QPSK signal. The Chromatic Dispersion (CD) is compensatedusing a simple transversal digital filter and Polarization Mode Dispersion (PMD) iscompensated using adaptive butterfly equalizer which is realized by applying theconstant-modulus algorithm (CMA). A nonlinear compensator (NLC) is used forcompensating the nonlinear effects based on the technique of multi-span backpropagation.A modified Viterbi-and-Viterbi phase estimation algorithm (workingjointly on both polarizations) is then used to compensate for phase and frequencymismatch between the transmitter and local oscillator (LO). After the digital signalprocessing is complete, the signal is sent to the detector and decoder, and then to theBER test set for direct-error-counting. The presented system is designed and simulatedusing OptiSystem (2011) software interfaced with MATLAB software R2011a forimplementing the DSP unit algorithms. The performance of each part of the system isanalyzed by showing the optical spectrum, RF spectrum, electrical constellationdiagrams, eye diagram and BER performance for different sampling rates and differentbit rates.

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