Dispersion Compensation

[Jamal]

Dear All,

Can anyone suggest a way for dispersion compensation after the signal passes through wavelength demultiplexer ?

[prakash jat]

hi jamal
try equalizer in regenerator section or universal dsp

[Jamal]

Where would I find the universal dsp ?

[alistu]

Hi Jamal,

You can find the universal DSP component in the OptiSystem receivers library, in the digital signal processing folder (The address that I have mentioned is certainly valid for OptiSystem version 13.0.3, and I think in OptiSystem version 14 it can also be found using the same address).

Regards

[prakash jat]

in receiver library

[Alessandro Festa]

What kind of signal needs dispersion compensation?

[Alessandro Festa]

Hi Jamal, any update on your project?

Best Regards,

Alessandro

[Jamal]

No Alessandro, I didn’t need to perform the dispersion compensation.
However if you want to have a look at my project please refer to my post here https://optiwave.com/forums/topic/signal-to-noise-ratio/

[Alessandro Festa]

Ok, thank you for your answer Jamal!

Best Regards,

Alessandro

[gaganpreet Kaur]

Hello even i am facing the same problem as jamal . i am getting OSNR as high as 93-105 dB for 16 channel system using Raman amplifier. i have used DCF for dispersion compensation. though i am getting Q factor and BER with clear eye diagrams but OSNR is as high as 104 dB. i want to know , is my system correct bcoz theoretically OSNR should not be that high.

[Alessandro Festa]

Hi gaganpreet, is noise checked in the Raman amplifier? Can you share your .osd file?

Regards,

Alessandro

[gaganpreet Kaur]

i think i did share it previously too with alistu but did’nt get any satisfactory answer. i have checked noise in Raman and i am getting BER of 10^-14. but i face this problem if a system is showing good eye results then OSNR is generally 80 plus else if OSNR is above 20dB(min)- required for any signal to be detected then BER eye diagrams are not very good.
Still i will share my file again with results by evening.

[Alessandro Festa]

Ok Gaganpreet, I cannot find your .osd in this discussion so if you share it I can maybe help you.

Looking forward to your file,

Alessandro

[Ranjeet Kumar]

Hi,
Methods of dispersion compensation after demux are we can use dispersion compensation in receiver. One refe. is http://www.sciencedirect.com/science/article/pii/S1068520012001617.
We use equalizer. I am uploading an osd of GVD equalizer

Attachments:

1. Equalizer-GVD.osd

[aasif bashir dar]

hi ranjeet,
the the link you have posted is the paper related to multi mode interference which we generally call multiple path interference because of different paths of each mode.
i think query is relation to chromatic dispersion in single mode conditrion after demux

with regards

[Aabid Baba]

Hi asif hello ranjeet,
i guess jamal is asking specific question. he wants to compensate dispersion after demux that means after separating channels. I think he has to compensate it right from the feeder fiber itself.
Asif you have discussed it recently. Ranjeet you can refer to that link where asif has explained it how to compensate dispersion for various cases.
Thanks
regards

[Rajguru M. Mohan]

Hi Jamal,
You have asked a good question because The positioning of the FBG along with EDFA plays an
important role in improvement of the optical systems performance.
When FBG is used at
transmitter side for dispersion compensation, it gives better
performance (minimum BER) as compare to when used for
compensation at receiver side. For 10km BER reduces from
6.73164e-319 to 1.87745e-322 with input power 4dB, for
20km BER reduces from 4.90116e-287 to 1.29445e-320 with
input power 2dB, for 40km BER reduces from 7.5984e-290 to
2.16954e-305 with input power 10 dB, for 50 km bit error
reduces from 1.10874e-102 to 4.16583e-181. Only for 30km
BER increases from 1.39294e-312 to 1.8834e-251. For 10, 20,
30, 40, 50 km to get minimum BER best FBGs length are
4mm, 14mm,10mm, 14mm, 14mm respectively. The gain of
the EDFA also plays an important role in systems
performance. For configuration (FBG at the transmitter end)

Thanks,

[umer ashraf wani]

http://www.google.ch/patents/US7885545
https://www.google.co.in/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&cad=rja&uact=8&ved=0ahUKEwiKz4CgttLMAhWIsI8KHelBA8UQFgglMAI&url=http%3A%2F%2Fwww.google.co.in%2Fpatents%2FUS6115156&usg=AFQjCNE_ode6xDlnUSXG1si5Jpp5UJEPvw&sig2=wnHNHycln9eYpd1RXat1mg
https://books.google.co.in/books?id=PvCN_biNky0C&pg=PA425&lpg=PA425&dq=dispersion+compensation+after+the+signal+passes+through+wavelength+demultiplexer&source=bl&ots=fVmModpW8U&sig=PWxPTgB46L8XCLvbtgERXKJ3iGQ&hl=en&sa=X&ved=0ahUKEwiKz4CgttLMAhWIsI8KHelBA8UQ6AEIMTAE
https://www.google.co.in/url?sa=t&rct=j&q=&esrc=s&source=web&cd=7&cad=rja&uact=8&ved=0ahUKEwiKz4CgttLMAhWIsI8KHelBA8UQFgg1MAY&url=https%3A%2F%2Fwww.google.si%2Fpatents%2FUS20040184730&usg=AFQjCNFgWa0H0K0jtiMt9MWUb7b2aY
3lVQ&sig2=gSwc6Y5pr6aHZM1ilCF7LQ
https://www.google.co.in/url?sa=t&rct=j&q=&esrc=s&source=web&cd=11&cad=rja&uact=8&ved=0ahUKEwiQ4aq1ttLMAhVBRY8KHfcjDnk4ChAWCBowAA&url=http%3A%2F%2Fwww.nptel.ac.in%2Fcourses%2F117101054%2Fdownloads%2Flect18.pdf&usg=AFQjCNFOPNDSuuxj9JrbcugqZ7w85PmyTw&sig2=wAjF3MXa4g3M8cOH-2XDyA&bvm=bv.121658157,d.c2I

[Nur1990]

hello..sorry for interrupt you guys… can anyone help me to solve my problem. actually i use numerical method (split step fourier method) in matlab to prove the effect of fiber losses, dispersion and non-linearity in optical soliton and also need to compare that result with optisystem. actually, i already got the result from optisystem for fiber losses, dispersion and SPM. i compared the effect of fiber losses (alpha), GVD (beta2), and SPM (gamma) based on the 3 physical length. (i picked 10km, 20km, and 30km).but here, i need to tally the result with matlab (split step fourier method) n must be the same result with optisystem. i try to change the coding, but it failed. since i picked 3 physical length in optisystem result, so i need to setup the same physical length in matlab coding to test the effect of fiber losses, GVD,and SPM.. i hope you guys help me to solve this problem.. im tired to thinking how to solve this problem. here i attached the coding and the result from optisystem.

[Nur1990]

matlab coding

Attachments:

1. NonNormalised_NLS_SSFM_28Nov20152.m

[Nur1990]

result optisystem

Attachments:

1. optisystem-result1.docx

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