Effects of Laser Linewidth on the Performance of DP-QPSK DWDM System

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Neeraj Sharma ◽  
Sunil Agrawal ◽  
Vinod Kapoor ◽  
Sumit Budhiraja
Keyword(s):  
Wavelength Division Multiplexing ◽  
Adaptive Equalization ◽  
Laser Linewidth ◽  
Phase Shift Keying ◽  
Channel Spacing ◽  
Wavelength Division ◽  
Differential Encoding ◽  
Quadrature Phase ◽  
Shift Keying ◽  
Dwdm System

AbstractThis paper analyzes the effects of laser linewidth on the performance of eight-channel dual-polarization quadrature phase-shift keying (DP-QPSK) dense wavelength division multiplexing (DWDM) transmission at 50 GHz channel spacing. The performance of differential encoding and Gray coding is compared with the system without any coding for the DP-QPSK DWDM system. It is shown that the differentially-encoded system performs better for lasers with linewidth (∆ν) greater than 0.04 MHz compared to the system with Gray coding and system without any coding. However, for lasers with linewidth lesser than 0.04 MHz, the three systems considered here perform equally and there is no need for differential or Gray coding in such a case. It is also shown that if we apply frequency offset estimation (FOE) before adaptive equalization (AE) in the digital coherent receiver then it further improve the performance of the differentially encoded system with lasers sources having linewidth even greater than 0.1 MHz.

Effects of local oscillator on the performance of DP-QPSK WDM system with channel spacing of 37.5 GHz

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Neeraj Sharma ◽  
Sunil Agrawal ◽  
Vinod Kapoor ◽  
Sumit Budhiraja
Keyword(s):  
Optical Power ◽  
Local Oscillator ◽  
Narrow Channel ◽  
Laser Linewidth ◽  
Phase Shift Keying ◽  
Channel Spacing ◽  
Modulation Format ◽  
Quadrature Phase ◽  
Shift Keying ◽  
Frequency Grid

AbstractDual-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.

Performance Analysis of DWDM System for Different Modulation Schemes Using Variations in Channel Spacing

2016 ◽  
Vol 37 (4) ◽  
Author(s):  
Divya Sharma ◽  
Y. K. Prajapati
Keyword(s):  
Phase Shift ◽  
Optical Network ◽  
Nonlinear Effects ◽  
Phase Shift Keying ◽  
Channel Spacing ◽  
Differential Phase Shift ◽  
Wavelength Division ◽  
Shift Keying ◽  
Modulation Schemes ◽  
Dwdm System

AbstractThis paper reflects the analytical study of dense wavelength division multiplexed optical network with different number of channels at various channel spacing in order to achieve higher data rates by means of few advanced modulation schemes. Bit error rate and quality factor are being analyzed with the variation in number of channels, channel spacing and transmission length of fiber. Advanced modulation schemes being compared here are carrier suppressed return to zero (CSRZ), duobinary return to zero (DRZ), modified duobinary return to zero (MDRZ), 33 % differential phase shift keying (33 % DPSK), 66 % DPSK and differential quaternary phase shift keying (DQPSK). It is keenly observed that CSRZ scheme with 100 GHz channel spacing serves best performance in terms of max. Q factor, min. BER and maximum transmission coverage upto 4,000 km for 16 and 32 channels DWDM system since CSRZ is high tolerant to nonlinear effects. On the other hand, MDRZ scheme with 75 GHz channel spacing exhibits transmission coverage upto 4,000 km and 4,500 km for 16 and 32 channels respectively, but with degraded signal due to effect of inter symbol interference (ISI).

DWDM Transmission with LEAF and RDF Structure in 40 Gb/s Single MZM with RZ-DPSK Modulation

2017 ◽  
Vol 38 (1) ◽  
Author(s):  
Hsiu-Sheng Lin ◽  
Po-Chou Lai
Keyword(s):  
Wavelength Division Multiplexing ◽  
Dispersion Compensation ◽  
Fiber Amplifier ◽  
Effective Area ◽  
Erbium Doped Fiber Amplifier ◽  
Differential Phase Shift ◽  
Wavelength Division ◽  
Modulation Format ◽  
Shift Keying ◽  
Dwdm System

AbstractWe propose the experiment transport of 48 Chs 40 Gb/s dense wavelength division multiplexing (DWDM) system that uses larger effective area fiber (LEAF) in combination with reverse dispersion fiber (RDF), which is a dispersion compensation device, in C band (1,530–1,560 nm) and L band (1,570–1,610 nm) wavelength range to solve the dispersion program. The single Mach–Zehnder modulation (MZM) format with erbium-doped fiber amplifier (EDFA) configuration to generate return-to-zero differential phase-shift keying (RZ-DPSK) modulation signal can compensate dispersion impairment in 48×40 Gb/s DWDM system. The proposed 48×40 Gb/s DWDM system successfully employs single MZM RZ-DPSK modulation format to reduce modulation complex configuration with EDFA to promote the power signal and using LEAF and RDF in 28 spans over 3,360 km ultra-long-haul fiber transmission successfully.

Transmission Performance of 112 Gb/s POLMUX QPSK Signal in OOK/DPSK WDM System

2020 ◽  
Vol 41 (2) ◽  
pp. 171-176
Author(s):  
Harmanpreet Kaur Sandhu ◽  
R.S Kaler ◽  
Gurpreet Kaur ◽  
Rajneesh Randhawa
Keyword(s):  
Phase Shift ◽  
Wavelength Division Multiplexing ◽  
Phase Modulation ◽  
Optical Signal ◽  
Phase Shift Keying ◽  
Error Vector Magnitude ◽  
Differential Phase Shift ◽  
Wavelength Division ◽  
Shift Keying ◽  
The Impact

AbstractIn this article, the impact of cross-phase modulation (XPM) and cross-polarization modulation (XpolM) on transmission of 112 Gb/s polarization multiplexed quadrature phase shift keying (POLMUX QPSK) signal in a wavelength division multiplexing (WDM) system has been investigated. This WDM system comprises of on-off keying (OOK) or differential phase shift keying (DPSK) channels. It is observed that the effects of XPM and XpolM are greatly reduced in a hybrid system of co-propagating OOK and DPSK channels. This is due to the dominance of phase modulation of DPSK signals rather than the intensity modulated OOK signals. The error vector magnitude (EVM) of the received optical signal is evaluated for the increase in number of neighbouring OOK and DPSK channels respectively within a bandwidth of 350 GHz. Also, the effect of increase in bit rate for two neighbouring OOK and DPSK channels has been observed individually on the 112 Gb/s POLMUX QPSK signal. It is concluded that DPSK signals display an improvement of −9.44 dB in EVM over OOK signals when there are eight neighbouring channels in the transmission system.

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