RZ vs NRZ

[Shahbaz Qureshi]

Which modulation format is better or suitable for Passive optical networks eg GPON or TWDM PON? Some papers tend to say RZ is better while NRZ is considered as a standard by ITU T.

[MHD NA]

Hi Shahbaz;
I think NRZ is better than RZ according to their performance in optical systems and that is clear by eye diagram that is clearer, when we use NRZ, than RZ (look at the attached photo) which makes Q- factor is bigger in NRZ.
For more information about your question you can make a look on the attached file.

Regards,

Attachments:

1. 

   EYE.png
   

1. 984157.pdf

[Shahbaz Qureshi]

Thanks Namera. Is the eye diagram attached for RZ appropriate? It forms X type of shape below or it can be like this aswell?

[alistu]

Hi Shahbaz,

Both have advantages and disadvantages. But NRZ encoding schemes are probably more convenient to use according to the current protocols and standards, so it is not just because NRZ might show better results.

Source: http://teledynelecroy.com/serialdata/serialdatastandard.aspx?standardid=439

Regards

[Shahbaz Qureshi]

Thanks Alistu. I understand. But the eye diagram attached by Namera for RZ is acceptable? or does it always have to look like the attached one.

Attachments:

1. 

   unnamed.png
   

[alistu]

It seems to be acceptable. The eye opening is good, and the Q-factor obtained also shows this. I have attached a file in you other topic regarding RZ signal modulation scheme which might be of more help to you. Please have a look at it here: https://optiwave.com/forums/topic/eye-diagram-for-rz/#post-25657

Regards

[Author]

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