OTDR

[Mohamed]

Hello guys, I need some help with my graduation project (OTDR) that I am facing a problem with the bidirectional coupler I think I am using it in a wrong way, Can please someone help me !

Attachments:

1. 

   otdr2-1.png
   

[Ahmad Atieh]

Hello Mohamed,
You need to add an optical delay component at the output of the fiber port, which is connected to the input port of the coupler. Usually, you need to do that whenever you use the same signal in the backward direction. Don’t forget to change the index to 1 from 0 in the visualizers used to view the signals after the delay elements.
Regards,
Ahmad

[Mohamed]

Dear Ahmed,
Thank you for replying first, I already did so and tried to receive signal power at the output port of the coupler using Optical power meter connected to the PIN photodiode, But the optical power meter gives me received signal power = -100 dbm and only reads noise power and the photodiode don’t detect anything.

Attachments:

1. 

   Bidierctional-Coupler-used.png
   

[Ahmad Atieh]

Dear Mohamed,
Please try to use OTDR and Phi-OTDR components in OptiSystem for your applications.
Your setup will not work for creating an OTDR.
You should be able to receive the back-reflected Rayleigh signal.
check the signal index of the visualizers.

[Mohamed]

Dear Ahmed,
I am so thankful for your help, I managed to receive the backscattered signal but its not delayed as it appears on the visualizer on the same exact time of the input signal as it is supposed that I see a time delay in my simulation between the input and output signals but only amplitude of the signal is affected, So can you tell me why is that ??

[Ahmad Atieh]

Dear Mohamed,
As I’ve mentioned earlier, the Rayleigh scattered signal you’ve collected in the bidirectional component doesn’t represent the localized scattered signal which typically is used in OTDR analysis. As I’ve mentioned also you may use the OTDR component in OptiSystem for any design or analysis.
I am not sure what you are you trying to achieve so, I can’t provide any extra feedback.
Regards,
Ahmad

[Mohamed]

The purpose of my simulation on Optisystem that i get results similar to practical design that I made, Which is to measure the backscattered light returning from the fiber as value and the delay time to be able to get the OTDR analysis correctly and to calculate the best pulse width with best resolution to get a better analysis for the fiber, So what i am doing now is configuring how my design is going to work.

[Ahmad Atieh]

you can do that in the OTDR component.

[Mohamed]

Which OTDR component ?

[Ahmad Atieh]

The OTDR component is located in the Default/Sensors library in OptiSystem.

[Mohamed]

Thank you I will try to use it

[Author]

Posts