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error when i use loop control

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(joined October 2014)
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hello everyone,i use a loop control to simulate a long distance system.however it occurs to a error.I use a bidirectional optic-fiber.can anybody give me a help?thank you in advance!

Responses (19):

    • #19049
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      Joseph Jiang
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      hello everyone,i use a loop control to simulate a long distance system.however it occurs to a error.I use a bidirectional optic-fiber.can anybody give me a help?thank you in advance!

    • #19059
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      Joseph Jiang
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      My friends,I want your help!thank you!

    • #19068
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      Ravil
      Participant

      Hi Joseph,

      I have a couple questions according to your attached scheme. First, what kind of regeneration scheme do you consider? In general, 3R regeneration is applied for long distance communications at the end of the transmission section due to several reasons. In your case, I don’t see any amplification at the receiver side. Second, what is the bandwidth or the bit-rate of your transmitted signal? If I’m not mistaken 0.1 nm corresponds to 12.5 GHz…

      +1
      • #19075
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        Joseph Jiang
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        hi,RAVIL,Thank you for your reply!the bit rate of my project is 100MBps.I just want to know why it ocurrs to error when i use the device loop control.as far as i know,the example use of loop control is unidirectional fiber rather than bidirectional fiber.i just want to know is it right for my use with loop control and bidirectional fiber.thank you!

    • #19073
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      Ravil
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      Here is one more detail which I forgot to mention before, unfortunately. Why did you choose Bessel Optical Filter at the receiver for your scheme? Can you indicate the reason why/if you consider it as an optimal choice? As far as I know, Raised Cosine Filter is used for Long Haul (long distance) transmission to reduce the inter-symbol interference…

      • #19076
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        Joseph Jiang
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        yes ,i agree with you.thank you for remind me!

    • #19080
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      Ravil
      Participant

      You are welcome, Joseph!

      Good luck with your project! Let me know if you have more questions, I will try to help or advise.

      • #19086
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        Joseph Jiang
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        Thank you,RAVIL!i just want to know is it right for my use with loop control and bidirectional fiber.There is anther question about the version 7.0 of optisystem.i find that the bit sequence length and samples per bit should not be more than 512bit and 64 samples per bit.if not ,it occurs to error.i want to know why it happens?thank you!

    • #19098
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      Abhishek Shrama
      Participant

      Reduce samples per bit and you will be able to increase the sequence length.

    • #19099
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      Abhishek Shrama
      Participant

      As per you attached screen shot. i an confused why you are using bidirectional fiber in unidirectional system? You have no tx rx at both sides u can use unidirectional fiber for this system

      • #19101
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        Joseph Jiang
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        thank you for your reply!the reason why I use the bidirectional fiber rather than unidirectional is that i want to add the effect of double rayleigth SCATTERING to my system.thank you!

    • #19119
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      Ravil
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      Hi Joseph,

      Sorry for my late reply… You can definitely use a loop control with a bidirectional fiber from the theoretical point of view. However, according to your attached scheme (by the way, is it your final version with all modifications you mentioned above?), I am not exactly sure how you are implementing this bidirectional connection, i.e. at each side of your scheme you have only one transmitter or receiver. Can you explain it to me briefly?

      • #19131
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        Joseph Jiang
        Participant

        Ravil,the reason why I use the bidirectional fiber rather than unidirectional is that i want to add the effect of double rayleigth SCATTERING to my system.however,it occurs to error when i use a bidirectional fiber especially when it is a short distance. I wander if it is a error use loop control when i add a bidirectional fiber.thank you!

        • #19168
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          Damian Marek
          Participant

          I am getting the same problem. I suggest skipping the loop and just daisy chaining the bidirectional fiber.

          Regards

        • #19184
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          Joseph Jiang
          Participant

          OK.THANK YOU DAmian,i will do that work!

    • #19121
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      Ravil
      Participant

      According to your question about bit sequence length and samples per bit (in case if you didn’t fix it yourself), you can find necessary directions in a guideline file OptiSystem_Getting_Started. According to them you should have:
      Time window = Sequence length * 1/Bit rate
      Good luck!

      • #19134
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        Joseph Jiang
        Participant

        hi ,ravil,i Understand what you had said and my question is that i find that the bit sequence length and samples per bit should not be more than 512bit,or it occurs to error.it will not happen when i simulate the same project in the optisystem 13.0.i want to know why it happens?thank you!

    • #19248
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      Ravil
      Participant

      Hi Joseph,

      I see what your question is now, just want to make sure what kind of error you are getting (screen shot would be helpful). If it’s related to the limitations of the current version you are using then the reason is obvious: lack of software resources. The other ideas may come up after I see the message error you are getting.

      • #19267
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        Joseph Jiang
        Participant

        OK,thank you so much!I think it may be that they have do optimization algorithm to calculate more samples in optisystem v13.0.

    • #19297
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      Ravil
      Participant

      Hi Joseph,

      You are welcome! And yes, I can remember from one of the previous forum about optimization question. The algorithm was optimized for higher capacity (in number of samples) in OptiSystem 13.0.

      Good luck!

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