Performance Optimization of WDM Long-Haul Lightwave Systems using Optimum Modulation Schemes.

  • Jalil Aziz Hamadamin Department of Electrical Engineering, College of Engineering, Salahaddin University-Erbil, Kurdistan Region, Iraq
  • Muhammed Abdulbaqi Ibrahim Department of Electrical Engineering, College of Engineering, Salahaddin University-Erbil, Kurdistan Region, Iraq
  • Salih Mustafa Saleem Department of electrical engineering, college of engineering , University of Dohuk
Keywords: Q-Factor, BER, WDM, RZ-DPSK


In this paper an optical communication system with N-Channel 40 Gb/s Wavelength Division Multiplexing (WDM) has been designed and optimized in the presence of Return-to-Zero Differential Phase Shift Keying (RZ-DPSK), Nonreturn-to-Zero (NRZ), Carrier Suppressed Return-to-Zero (CSRZ) and Modified Duo binary Return-to-Zero (MDRZ) modulation schemes. The system simulation is done using Optisystem simulator version-14 with multiple span Standard Single Mode Fiber (SSMF) transmission and the launched optical power range from (-10dBm to 10dBm). The effect of increase in launched power is studied in terms of Quality factor (Q-Factor), Bit Error Rate (BER), nonlinearity impairments and Eye Opening Penalty (EOP) for different modulation formats. The simulation results show that NRZ has highest Q-Factor of (38) and lowest BER with high nonlinear effects and system performance degradation with the increase of input optical power, while CS-RZ has the lowest Q-Factor of (6) with little nonlinear effect. On the other hand, RZ-DPSK offers high Q-Factor of (32) with high tolerant to nonlinear impairments and the system performance remains resilient to nonlinearity with the increase of input power. It is observed that RZ-DPSK has the lowest EOP that reaches only to 0.7 while NRZ has the highest EOP in which reaches to 4.5. Simulation results also show that RZ-DPSK has higher, wider and clearer eye diagram than other modulation formats. It is concluded that the light wave system with RZ-DPSK format offers the best performance, higher tolerance to nonlinearity and higher dispersion tolerance among other modulation formats.


Cheng, K.S. and Conradi, J., (2002) ‘Reduction of pulse-to-pulse interaction using alternative RZ formats in 40-Gb/s systems’, IEEE Photonics Technology Letters, 14(1), pp.98-100.
Chenika, A., Temmar, A. and Seddiki, O., (2014) ‘Transmission of 4× 40/10Gbps in a WDM-PON using NRZ-DQPSK/ASK modulation’, Optik-International Journal for Light and Electron Optics, 125(20), pp.6296-6298.
Grobe, K. and Eiselt, M., (2013) ‘Wavelength Division Multiplexing: A Practical Engineering Guide’, John Wiley & Sons.
Hoshida, T., Vassilieva, O., Yamada, K., Choudhary, S., Pecqueur, R. and Kuwahara, H., (2002) ‘Optimal 40 Gb/s modulation formats for spectrally efficient long-haul DWDM systems’, Journal of lightwave technology, 20(12), pp.1989-1996.
Kaler, R.S., Kamal, T.S. and Sharma, A.K., (2002) ‘Simulation results for DWDM systems with ultra-high capacity’, Fiber &Integrated Optics, 21(5), pp.361-369.
Kaler, R.S., Sharma, A.K. and Kamal, T.S., (2002) ‘Comparison of pre-, post-and symmetrical-dispersion compensation schemes for 10 Gb/s NRZ links using standard and dispersion compensated fibers’, Optics Communications, 209(1), pp.107-123.
Li, L., Chen, Y.T., Zhang, J.J., Cao, J.F. and Li, Z.R., (2014) ‘Analysis of intensity modulation performance in WDM-PON network’, Optik-International Journal for Light and Electron Optics, 125(24), pp.7170-7174.
Liu, Z., Kakande, J., Kelly, B., O'Carroll, J., Phelan, R., Richardson, D.J. and Slavík, R., (2014) ‘Coherent optical OFDM based on direct modulation of injection-locked Fabry-Perot lasers’, In Optical Communication (ECOC), 2014 European Conference on (pp. 1-3), IEEE.
Méndez, A. and Morse, T.F. eds., (2011) ‘Specialty optical fibers handbook’, Academic Press.
Mishina, K., Maruta, A., Mitani, S., Miyahara, T., Ishida, K., Shimizu, K., Hatta, T., Motoshima, K. and Kitayama, K.I., (2006) ‘NRZ-OOK-to-RZ-BPSK modulation-format conversion using SOA-MZI wavelength converter’, Journal of lightwave technology, 24(10), pp.3751-3758.
Sheetal, A., Sharma, A.K. and Kaler, R.S., (2010) ‘Simulation of high capacity 40Gb/s long haul DWDM system using different modulation formats and dispersion compensation schemes in the presence of Kerr's effect’, Optik-International Journal for Light and Electron Optics, 121(8), pp.739-749.
Singh, A., Sharma, A.K., Kamal, T.S. and Sharma, M., (2009) ‘Simulative investigations of power penalty for DWDM link in the presence of FWM’, Optik-International Journal for Light and Electron Optics, 120(12), pp.579-584.
Singh, J. and Kumar, N., (2013) ‘Performance analysis of different modulation format on free space optical communication system’, Optik-International journal for light and electron optics, 124(20), pp.4651-4654.
Wei, X., Liu, X., Simon, S.H. and McKinstrie, C.J., (2006) ‘Intrachannel four-wave mixing in highly dispersed return-to-zero differential-phase-shift-keyed transmission with a non-symmetric dispersion map’, Optics letters, 31(1), pp.29-31.
Winzer, P.J. and Essiambre, R.J., (2006) ‘Advanced optical modulation formats’, Proceedings of the IEEE, 94(5), pp.952-985.
Xu, C., Liu, X. and Wei, X., (2004) ‘Modulation formats for high spectral efficiency fiber optic communications’, IEEE J. Quantum Electron, 10, pp.281-293.
Yong, C., Jihong, C., Xi, Q., Feng, Z. and Shuisheng, J., (2008) ‘Performance comparison for RZ-DPSK signal in DCF-based and CFBG-based dispersive transmission system’, Optik-International Journal for Light and Electron Optics, 119(9), pp.441-445.
How to Cite
Hamadamin, J., Ibrahim, M. and Saleem, S. (2019) “Performance Optimization of WDM Long-Haul Lightwave Systems using Optimum Modulation Schemes.”, Zanco Journal of Pure and Applied Sciences, 31(5), pp. 121-129. doi: 10.21271/zjpas.31.5.13.
Mathematics ,Physics and Engineering Researches