back2back

[Heitor Galvao]

What is back2back? How can I put this system please find attached in back2back and validate the transmitter with it after you add again the fibers to see if everything is ok?

Attachments:

1. Lesson-3b-Optical-Systems-WDM-design1.osd

[Damian Marek]

Hey Heitor,

1) A back to back transmission scheme describes a system where the receiver and transceiver are directly connected with no transmission link. As an example in your attached file, everything inside the loop control would be disabled.

2) I’ll also respond to your private message about the frequency comb project. I’ve modified it in the attached project file to a back to back system. You can either delete the fiber, amplifiers and dispersion compensating fibers or you can directly disable the component in the Simulation tab of the components. I fixed your project file by modifying the receiver. The channels were actually 193.2-193.9 and the cutoff frequency was set in terms of the symbol rate, which should have been 10 Gb/s

Regards

Attachments:

1. Lesson-3b-Optical-Systems-WDM-design-Comb.osd

[Heitor Galvao]

Good afternoon Damian I try to open the file in optisystem 13 and the following message appears

Attachments:

1. 

   Capturar.png
   

[Damian Marek]

I’m not sure why this is happening. It may be because I have a more recent version of OptiSystem than you (13.0.1).

[Heitor Galvao]

Goodnight Damian I couldn’t open your palette, do give some error, more made the modifications you cited and actually minlog(BER) improved considerably, but the OSNR, assumes zero value, what do you suggest?

Attachments:

1. WDM-comb-design-worksheet.pdf
2. Lesson-3b-Optical-Systems-WDM-design-Comb-damian.osd

[Damian Marek]

Ok I think I know where the confusion is coming from. The WDM Analyzers is having a hard time finding the different channels due to the way that you generated the frequency comb. Since the frequency comb was seeded with a 193.1 THz laser the signal is “attached” with that frequency value and the WDM Analyzer is assuming that is the center frequency. If you right click the WDM Analyzers and choose “Extend Scan” it will correctly identify the remaining channels and give normal values.

Regards

[Heitor Galvao]

Please look what I sent by private message

[Heitor Galvao]

Good afternoon I’m with a doubt relevant Damian who is as follows: when I put a WDM analyzer after the loop control (fiber + amplifier), there are acceptable values of OSNR, more so that there is a but if placed a WDM analyzer in the first channel for example the demultiplexer he will give a value apoximado with WDM anaylzer placed in control loopI understand that the values are equal, is there any kind of loss to give such a difference in values of OSNR? In the annex you see the table regarding the WDM analyzer placed in the control loop, and the right of the WDM table corresponds to the WDM placed on the first channel of the demultiplexer.

Attachments:

1. 

   Capturar1.png
   

[Heitor Galvao]

the same reasoning to the optical comb generator

[Ravil]

Hi Heitar, it looks like you have some nonlinearities (according to your OSNR distribution) in your group signal. What is the input power at your MUX?

[Heitor Galvao]

What will interfere to arriving at the power multiplexer?

Attachments:

1. 

   Capturar2.png
   

[Ravil]

Also, do you have any active element before MUX in your scheme? (I can’t see this part on your pic…)

[Heitor Galvao]

active element mean?

[Ravil]

The active elements (amplifiers, boosters, power normalizers, freq. converters) are changing the main characteristics of your group signal.

[Ravil]

In other words, high channel peak power produced by active elements can induce nonlinear effects in group signal of WDM.

[Ravil]

By the way, I can see only transmitted power on your screen shot. Did you measure the power at the input of your MUX?

[Heitor Galvao]

Look, I understand you meant non-linear effects more about the power that is being introduced in the multiplexer, so is there a way to measure it up to where I know is using a WDM analyzer, because until seeing the multiplexer component properties do not have this option.

Attachments:

1. 

   Capturar.jpg
   

[Ravil]

I’d use WDM analyzer for measuring power in this situation as well

[Ravil]

According to your last uploaded pic you don’t have any deviation in OSNR (as it was before) and it keeps its high value. Do you still have questions about your results?

[Heitor Galvao]

Thank you very much its cooperation was very important

[Ravil]

You are welcome

[Heitor Galvao]

Thank you

[Author]

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