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Spontaneous Raman scattering

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(joined December 2014)
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Hi,

I am currently working on project for distributed temperature sensing based on Raman scattering. I’ve tried to simulate such system but in order for project to show correct results I need to get anti-Stokes and Stokes band of Raman scattering right. Somehow anti-Stokes scattering is not showing good results at all, and Stokes band is also not quite good. Does anyone have any suggestion how to get this work. Also how can I see Raman signal on spectrum analyzer without adding noise parameters in bidirectional fiber.

One question off topic: Why does EDFA spectrum change it’s peak wavelength dependent of signal power, shouldn’t it be at 1530-1531 at all time.

Thanks in advance… 🙂

Responses (7):

    • #16602

      Hi,

      I am currently working on project for distributed temperature sensing based on Raman scattering. I’ve tried to simulate such system but in order for project to show correct results I need to get anti-Stokes and Stokes band of Raman scattering right. Somehow anti-Stokes scattering is not showing good results at all, and Stokes band is also not quite good. Does anyone have any suggestion how to get this work. Also how can I see Raman signal on spectrum analyzer without adding noise parameters in bidirectional fiber.

      One question off topic: Why does EDFA spectrum change it’s peak wavelength dependent of signal power, shouldn’t it be at 1530-1531 at all time.

      Thanks in advance… 🙂

    • #16675
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      Damian Marek
      Participant

      Hi Ivan,

      Can you describe a little more how the Raman scattering is not accurate? You want to isolate the generated Raman signal from the input signal or just view the total output signal?

      The EDFA spectrum can change from a couple of factors. For example, inhomogeneous broadening (spectral hole burning) of the spectrum could reduce the gain at the peak (if a high power signal is present) and thus shift the apparent peak to a different frequency.

      Regards

    • #16678

      Hi,

      I uploaded spectrum that I am getting. I am interested in backscattering Raman. Anti-Stokes band should be a bit lower in power than Stokes band but I am getting difference of 100dB between them and even more. That is a lot. Also Anti-Stokes is lower than noise that I added in bidirectional fiber to even see spontaneous Raman scattering. Also there is backscatter Rayleigh. I’ve tried to change Raman coefficient but only Raman Stokes band is getting stronger, and Raman Anti-Stokes band is getting weaker with bigger coefficient. Pump power is set at 1W, fiber is 10km long.

      Thanks in advance,

      Ivan

      Links to images:

      https://www.dropbox.com/s/0628qy5f2rvynjs/Raman1W0.310km300K.bmp?dl=0
      https://www.dropbox.com/s/8gfng69dahsst4q/Raman1W0.9910km300K.bmp?dl=0

      • #16743
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        Damian Marek
        Participant

        Could you also help to attach your project file (.osd)? Is there a specific paper or article you have as a reference that you are having trouble reproducing or is it mainly the large difference in Stokes/Anti Stokes?

        Regards

    • #27335
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      Kadambari Sharma
      Participant

      hi ivan please attach your .osd file. So that we will get more idea about your problem.

    • #27336
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      Kadambari Sharma
      Participant

      the link for the spectrum files is giving error.

      • #27337
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        Alessandro Festa
        Participant

        This is a 10 month old conversation so he probably already solved his problem 🙂

    • #29236
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      Kadambari Sharma
      Participant

      hi ivan can you please attach your .osd file. It is a interesting topic and i would like to know more about it as i am new in this field.

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