Value of Nonlinear coefficient

[Ajay Vyas]

Hi Members
Am working on nonlinear compensation method, I find a paper attached with this mail regarding the same. In which author mentioned some specification regarding the optical fiber and DCF. I higher light that specification.
I have little doubt about the term nonlinear coefficient. Is it gama or nonlinear index n2, because it unit is give /w/km that is gama. Then how we can chose in OptiSystem. If I calculate the n2 with reference to gama then it value is 32e-5. I simulate with this value but simulation is not completed upto 2 hour.
Please check it help me to understand those specification

[Ashu verma]

Hello Ajay Vyas
Nonlinear coefficient really depends upon n2(non-linear coefficient),Aeff of optical fiber.In the paper you have attached value of gamma is 2.09/w/Km for SMF and 6.04 in the case of DCF.Units of n2 is m2/W and for Aeff in um2.you can calculate gamma by using formula

Gamma=2*pi*n2/Wavelength*Aeff

Default value of n2 in SMF28 is 26e-21 and Aeff is 70um^2.Rest it vary according to application or alter by the manufacturer

Discussion already has done on this topic.Please check the link given below

Is this value for non linear coefficient practical?

Regards

[Ajay Vyas]

Thanks Samsung
This is very useful for me.
I put the value of gamma , wavelength , Aeff then calculate the value of n2

[Ashu verma]

Welcome Ajay vyas
Try to find gamma by putting all the values and don’t forget to consider there units.

[Ajay Vyas]

I calculate the Aeff with consideration of n2 & gamma value. It is run but still need to improvement in constellation diagram.

[Ashu verma]

Hello Ajay
Since you are working on OFDM system then must go for opc to compensate effects of non linearities in your system.Because it enhance your transmission distance by compensating the high value of gamma in the case of DCF.Go for lower power if your system taking to much time for calculations.If you are using OPC in system then you can go for higher power too.

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