Problem in BER Analyzer

[Jawaher Alshehri]

Hi all ,
I used the OptiSystem program for my project and I done everything requirements , but I have problem in the last step BER analyzer
It’s can’t show the simulation, Can you help me?

Attachments:

1. 

   111.jpg
   

[alistu]

Hi Jawaher,

This happens in many cases when the signal is corrupted in the receiver. Either there i a problem with your implementation, or the signal has noticeable error. can you please upload the osd file so that I would have access to the implementation and be able to make the necessary changes to it?

Regards

[Jawaher Alshehri]

thank you Alistu
this is my project file

Attachments:

1. G-project-12.osd

[alistu]

Your system bit rate is 385Gps and you have chosen the WDM channel bandwidth 192.5 GHz according to the bit rate, while the channel spacing (lasers frequency step) is 100GHz so the channels overlap. You should either change the bit rate and WDM bandwidth, or change channel spacing to avoid the overlap.

Regards

[Jawaher Alshehri]

This is requirement for our project :
• The data rate is 3.85*10^11 bit/sec.
• The cable length is 434.5 Km.
• The link type is full duplex single mode step index fiber.
• The amplifier spacing for every 96 Km.
• The wavelength window is 1500 – 1600 nm.
• The operating wavelength is 1550.

we should to design 16 channel between tow cities and the Total distance between the cities = 434.5

I will try to change & Tomorrow i will tell you what happened with me …

Thank you so much

[alistu]

You’re welcome. And by the way, I noticed you hadn’t used Loop component in your design. You can use it to repeat your transmission line pattern instead of repeating it over and over in series and letting it take up space in the layout. You can see how to use it in many of the OptiSystem samples.

Regards

+1

[Jawaher Alshehri]

I have question how can i find DCP component , i can not find it
also BER Test set it’s not the same in optisystem program

in optisystem show BER like pic2

Attachments:

1. 

   Capture111.jpg
   

2. 

   Pic-2.jpg
   

[alistu]

DCF is the same component as the optical fiber available in optical fibers library, with dispersion properties set in order to compensate for the dispersion of the main fiber in the transmission line.

In order to see any of the parameters in light green for BER test set you can right click on the component and choose “component results”. Now you can choose “display” for any of the parameters.

Regards

[Jawaher Alshehri]

OK I know to create DCF .. thank you
but how can i see the value of channel spacing because i want to edit it .

BER still like pic 2 i don’t find the shape in pic 3
look at the blue arrow

Attachments:

1. 

   pic2.jpg
   

2. 

   pic-3.jpg
   

[alistu]

In WDM systems, channel spacing is chosen by designer. It is up to you to decide the spacing between channels by choosing the center frequency of each of the channels and apply it to transmitter lasers. The channel spacing is chosen with respect to the channels bandwidth, so as to avoid overlap.

[Jawaher Alshehri]

OK , but how can i find it in optisystem as a chose .

[alistu]

You can simply double-click on the laser and set the laser frequency value in the component properties. You can also use CW laser array instead of using multiple CW lasers for a WDM laser. Both CW laser and CW laser array components can be found in optical sources in transmitters library.

[Jawaher Alshehri]

I create new project still can’t show BER analyzer 🙁

Attachments:

1. arry.osd

[alistu]

You have set the frequency of the CW laser according to what was discussed. However, you haven’t set the properties of the WDM multiplexer and WDM demultiplexer (bandwidth and channel spacing) according to the same characteristics in the laser array. The channel spacing is 0.1 THZ there, while it is 0.05THz in laser array.

[Jawaher Alshehri]

Finally i can see the BER Q-Factor … etc expect the BEAR pattern not see
Is it normal or error??

Attachments:

1. 

   11111.jpg
   

[alistu]

I don’t think this is an error or any sign of a corrupted received signal, since you have got all the other numbers and the other plots are being shown (I haven’t paid much attention to BER pattern and have always checked only min. BER plot and other plots to analyze the system performance, though).

[feras]

hi جواهر
the BER is very good in your project because the BER must be smaller than 1 and it will be better if it is smaller than 0.5 , and the Q factor must be near 5 and u have agood Q factor as can i see

[Jawaher Alshehri]

Thank you so much AliStu & Feras for feedback ..
Kindly if you are enable to give some detailed information or references about what is the meaning Q-factor , Min BER , Threshold and BER pattern ?

[alistu]

You’re welcome Jawaaher. Here I have attached a file that was uploaded in one of the forum pages a while ago and I believe it explains Q-factor and how it shows the system performance and also how it is calculated in BER analyzer really well. There have also been some discussions about this in the forums.

Regards

Attachments:

1. Q-Factor.pdf

[alistu]

The BER you have achieved is good, but it is not enough for a real communication system. The BER for practical communication systems should at least be 10e-9 or 10e-12, which correspond to Q-factors of 6 to 9. You may be able to achieve it by using more launched power at the transmitter, or some other way in your system.

Regards

[atef ibrahim]

hello friends !! i have the same problem and this is my work !
please can anyone help me ?

[THarun Kumar Racha]

(Awaiting moderation)

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