BER vs Wavelength

[Alessandro Festa]

Hi all, I typically run wimulation for WDM system with many channels propagating in the fiber. As an outcome of the simulations, I need to plot OSNR vs wavelength and BER vs wavelength.
The first item is trivial, because with WDM analyzer component I can simply cut and paste OSNR and wavelengths. But for the second I need to di manually, because BER analyzers are stand-alone components and I did not find a way to have all BERs in a single components. Is there a better way to do that?

[Damian Marek]

Unfortunately, I think you are right about doing it manually. The “cleanest” solution I can think of is using a filter and parameter sweep and run simulations with the filter moving from wavelength to wavelength. You could then plot the BER as a function of center wavelength of the filter. As of right now though we do not have a WDM Receiver.

The other more involved solution would be to scripting. It should not be that hard to create any number of BER Analyzers and then save the BER and wavelength data.

Regards

[Alessandro Festa]

Thanks Damian for your quick reply. The first solution is not doable because the system would use a wavelength at a time, while I need all of them propagating in the fiber together.
Can you explain a bit more the second solution? My projects usually have a number of BER analyzers equal to the number of WDM channels (I have projects with 40 BERs!), how can I save BER results with a script?

[Damian Marek]

Alessandro,

I made a script with snippets from some of our tutorials, mainly the tutorial on exporting to Excel. With the script I have a variable called numChannels, which you can modify to be any integer value. The script then generates and modifies components to create a layout like the 20 channel example attached. It then runs the simulation and saves the results from the BER Analyzers into Excel, which can then be used to plot the BER as a function of frequency. I will let you change the frequency to wavelength 🙂

With this example and an understanding of VB Scripting you should be well on your way to solving your particular problem. Hope it helps!

[Alessandro Festa]

Hi Damian, thank you very much for your help! This will save me a lot of time in my simulations…I will look into that tomorrow once in the office.
Thanks again!

[Alessandro Festa]

Hi Damian, I tried to run the script but I get an error for line 29, which is Set Excel = CreateObject(“Excel.Application”). Should I maybe change the application named based on my PC settings/language?

[Damian Marek]

Yes, I am not too sure why it would not be working for you. What does the error say? I think also sometimes Visual Basic Script can be disabled for security reasons. Try opening Excel with straight Visual Basic and no OptiSystem.

Regards

[Alessandro Festa]

Hi Damian, i think you are correct because when I open certian .xls files Excel gives me a warning concerning VBscript/ActiveX which cannot be enabled. I will investigate further on my settings. Thanks!

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