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.



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”



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)”



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




IJEECS

ISSN 2348-117X

Volume 6, Issue 6

June 2017

Figure 11“Eye Diagram at


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

[1] S.P. Singh and N. Singh,Nonlinear effects in optical

fiber ORIGIN, MANAGEMENT AND

APPLICATIONS(2007).

[2] Agarwal, G.P,Nonlinearity Fiber optics, 3rdedition,

Academic press, San Diego, CA, (2001).

[3] Manjit Singh, Ajay.K.Sharma,

R.S.Kaler,Investigations on optical timing jitter in

dispersion managed higher order soliton

System(2011).

[4] Gousia, G.M.Rather, Ajay.K.Sharma, “WDM-

OTDM based spectral efficient hybrid multiplexing

technique inherent with properties of bandwidth

elasticity and scalability” (2010).

[5] Ajay.K. Sharma, S.K. Wadhwa, T.S.

Kamal,Robustness of NRZ, RZ, CSRZ and CRZ

modulation on fiber nonlinearities and amplifier

noise at 40 Gbps for (OC-786) long haul link (2008).

[6] Manjit Singh, Ajay.K.Sharma, R.S. Kaler, Manoj

Kumar, Timing jitter dependence on data format for

ideal dispersion compensated 10 Gbps optical

communication system (2007).

[7]VishalSharma, Amarpal Singh, Ajay.K.Sharma,

Analysis and simulation of the effect of spectral

width over intensity noise under the impact of higher

order dispersion parameters in the optical

communication systems(2008).

[8] N Rauter and R Lammering, Numerical simulation

of elastic wave propagation isotropic media

considering material and geometrical nonlinearities

(2015).

Performance Analysis of XPM Nonlinear effects on WDM Link · Performance Analysis of XPM Nonlinear...

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