Performance Analysis of XPM Nonlinear effects on WDM Link · Performance Analysis of XPM Nonlinear...
Transcript of Performance Analysis of XPM Nonlinear effects on WDM Link · Performance Analysis of XPM Nonlinear...
74 Surajmukhi, Manju, Kuldeep Singh
International Journal of Electronics, Electrical and Computational System
IJEECS
ISSN 2348-117X
Volume 6, Issue 6
June 2017
Performance Analysis of XPM Nonlinear effects on WDM Link
Surajmukhi*, Manju**, Kuldeep Singh***
*(Department of Electronics and communication, Guru Jambheshwar University, Hisar)
** (Department of Electronics and communication, Guru Jambheshwar University, Hisar)
***(Assistant Professor,Department of Electronics and communication, Guru Jambheshwar University, Hisar)
ABSTRACT
In this paper, a simulation model with NRZ modulation for reducing the nonlinearity has been proposed by use of
different parameter like length, power and dispersion. Firstly, we evaluate the effect of XPM nonlinearity on the output
spectrum. The simulated results show that the fiber link with a distance of approximately 120 km at transmitted power of
10 mw may be designed with value of Q factor and BER is quite above the threshold level. The performance of four
channels on WDM has been evaluated in terms of Q-factor, BER against power, dispersion and length to study the
nonlinear effects. The main reason of nonlinear effects are change in inelastic scattering and refractive index of the fiber
The performance of designed Cross phase modulation has been executed for evaluation in terms of BER, Q factor and
eye diagrams.These effects are analyzed with OPTSIM tool. It has investigated that fiber having the distance of 40 km at
the power10and dispersion 1.5 ps/nm/km the value of quality factor is found to be 18.588[dB], 25.384662[lin].
Keywords-BER, Q-Factor, SPM, XPM.
1 INTRODUCTION
It is an investigated that fiber optical technology is
good to fulfill the user requirement for more
bandwidth and high data rate with minimum losses.
More bandwidth and high data rate are used in
WDM and different applications.The optical power
should be large to overcome power penalty effects
to obtained good design goal. It is better when fiber
is linear. But in actually fiber nonlinear effects
occur when power increases. These nonlinear
effects are intensity and power depended. When the
power level increases above 10 mw different type
of nonlinearity comes.It is necessary to study these
effects for improve the performance of any system.
It occurs due to change the refractive index of
medium with intensity. The nonlinear effects are in
optical fiber are
SPM
XPM
FWM
For electromagnetic fields, any dielectric medium
act as nonlinear medium. The origin of nonlinearity
lies in a harmonicmotion of bound electrons under
the influence of an applied electric field. The total
polarization P induced by electric dipoles is not
linear.
P =𝜀0𝜒(1) E+ 𝜀0𝜒
(2)𝐸2+ 𝜀0𝜒(3)𝐸3+ ………. [1]
Where𝜀0is the permittivity of vacuum and𝜒(𝑘)is
𝑘𝑡ℎorder susceptibility. The dominant contribution
is provided by linear susceptibility. The second
order susceptibility is responsibility is responsible
for second order harmonic generation. The third
order susceptibility is responsible for lowest order
nonlinear effects. When no of channel are very
large in WDM then each channel effected by rest
of channel in 128 WDM channel .Each channel
carry 2-3 mw power . So effect of XPM are strong
on WDM each channel carry small power. XPM
cause pulse broadening which is not symmetric.
The non-linearity in refractive index is known as
Kerr nonlinearity [2]. These nonlinearity induces
the phase modulation of modulation of propagating
of signal isknown as Kerr effects. In single
wavelength called SPM and in multiple
wavelengths called XPM.
75 Surajmukhi, Manju, Kuldeep Singh
International Journal of Electronics, Electrical and Computational System
IJEECS
ISSN 2348-117X
Volume 6, Issue 6
June 2017
1.1Cross phase modulation
Cross phase modulation is a nonlinear effect where
one wavelength of light can affect the phase of
another wavelength of light. When the optical
power from a wavelength impacts the refractive
index, the effect of new refractive index on another
wavelength is known is XPM. It causes change the
phase of signal and pulse broadening. Soto reduce
the nonlinearity effects we use a fiber that has some
dispersion. [2]
2EXPEIMENTSETUP
The experiment consist of blocks, and a scope in
output to measure the BER,Q factor and to plot the
eyediagrams.The simulation setup with centre
frequency 193.025HZ for first channel, 193.075 for
the second channel,193.125 for the third channel
and 193.175 for the last channel simulated XPM
optical link by using NRZ modulation format.In
optical link fixed gain output amplifier has been
added to remove the losses that occur during
transmission of data.
Figure 1 “block diagram of 4 channel Cross phase modulation”
3 Simulation work
We simulate the XPM by varying dispersion, length
and power. By using these we can mitigate and
overcome the nonlinear effects. In this simulation
model we use the frequency 193.025 of first
channel and 193.075 of 2nd channel.193.125 of third
and 193.175 for the fourth channel. We investigate
that by using the optical match filter good results
are obtained instaed of using the Besselfilter.
3.1 XPM analysis and results
It defines the input spectrum of input signal and the
frequency of signal which is to be transmitted. The
measurement component used for this optical
Spectrum Analyzer.
Figure 3 “ input spectrum”
76 Surajmukhi, Manju, Kuldeep Singh
International Journal of Electronics, Electrical and Computational System
IJEECS
ISSN 2348-117X
Volume 6, Issue 6
June 2017
It definestheoutput spectrum of input signal after
passing through the fiber. But due to XPM
nonlinearity the 4channel spectrum becomes broad
appear like as shown in fig (1.7).
Figure 4 “output spectrum”
It shows the quality of signal which is received at
the receiver. The value of quality factor should be
above 16 in case of dB and above the 6 in case of
linear scale.
Figure 5 “ Q Factor Versus Dispersion(0,2,4.8.10
ps/nm/km)”
The value of BER will be decrease with increase in
dispersion.It should be below 10−9 to achieve good
performance.
Figure 6“BER Versus dispersion”
Q-factor shows the quality of signal which is
received at the receiver. The value of quality factor
should be above 16 in case of dB and above the 6 in
case of linear scale.
Figure 7”Quality Factor Versus
length(50,60,70,80,90 and 100)”
77 Surajmukhi, Manju, Kuldeep Singh
International Journal of Electronics, Electrical and Computational System
IJEECS
ISSN 2348-117X
Volume 6, Issue 6
June 2017
BER defines as the no of errors to the total no of bi
transmitted.The value of BER will be decrease with
increase in dispersion. It should be below 10−9 to
achieve good performance.
Figure 8“BER versus length”
An eye diagram defines the quality of signal to be
transmitted or defines the quality ofsignal
receivedat the output. We will take these eye
diagrams by using electrical scope.
Figure 9“Eye diagram at
dispersion(8nm/ps/km),Length(50km),power(10mw)”
Figure 10“Eye Diagram at
dispersion(10nm/ps/km),Length(50km)”
Figure10 “Eye Diagram at
dispersion(16nm/ps/km),Length(90km)”
78 Surajmukhi, Manju, Kuldeep Singh
International Journal of Electronics, Electrical and Computational System
IJEECS
ISSN 2348-117X
Volume 6, Issue 6
June 2017
Figure 11“Eye Diagram at
dispersion(17nm/ps/km),Length(100km)”
4 CONCLUSION
The result have obtained for WDM system using
NRZ modulation format with narrow channel
spacing to evaluate the performane in terms 0f Q
factor , BER and eye diagrams.Four different
frequency (193.025,193.075,193.125 and 193.175)
have been taken foe evolution of WDM in terms of
BER, Q factor and eyediagrams.The sysyem with
NRZ modulation format shows good result up to
120 km distance for optical fiber communication.
At distance of 150 km BER is very high and quality
factor is not so good. At frquency
193.025,193.075,193.125 and 193.175 the value of
the quality factor is 10.1205[lin],20.14080Db. The
value of BER are 6.82031e-024 is found to be at
length 120, power 12mw and the dispersion
ps/nm/km.
5 REFERENCES
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fiber ORIGIN, MANAGEMENT AND
APPLICATIONS(2007).
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Academic press, San Diego, CA, (2001).
[3] Manjit Singh, Ajay.K.Sharma,
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[4] Gousia, G.M.Rather, Ajay.K.Sharma, “WDM-
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