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crosstalk

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    • July 14, 2015 at 11:09 am #22414
      Saja Al Mamoori
      Participant

      I need to measure the amount of crosstalk in wdm network. Node crosstalk and fiber crosstalk (due to SRS, XPM, FWM). I am using optisystem.

    • July 15, 2015 at 6:34 am #22445
      Abhishek Shrama
      Participant

      Hello Saja Al Mamoori!!
      Welcome to optisystem forum!!
      There has already been a number of discussions regarding crosstalk
      on forum. Check the following links and find answers to your queries and I hope you will find a lot more than your questions.

      CROSSTALK

      CROSSTALK

      CWDM crosstalk model

    • July 15, 2015 at 6:37 am #22446
      Abhishek Shrama
      Participant

      Also I would like to add that if you want to take readings take the readings of Q factor,BER and received power etc with switching off and switching on the non linear effects( SPM. XPM etc as you mentioned).
      Compare the parameters received and you will know the difference.

      • July 15, 2015 at 5:11 pm #22479
        Saja Al Mamoori
        Participant

        I have run my simulation. WDM: 8 channels multiplexed with 8*1 MUX, go through fiber 100 km, then DMUX and a receiver. I am testing the BER visualizer I got no values for Max Q-factor = 0 and Min BER = 1 and the eye diagram is not clear.

        Thanks for any help

        • July 16, 2015 at 6:42 am #22495
          Ashu verma
          Participant

          Attach your system file for better information.

      • July 15, 2015 at 7:21 pm #22481
        Saja Al Mamoori
        Participant

        Thanks, but how do I switch the nonlinear effects on and off?

        Regards,

    • July 15, 2015 at 9:31 am #22461
      Ashu verma
      Participant

      Hello Saja
      Abhishek gave you some good links,i just want to add that if you want measure the crostalk in the WDM systems then for FWM you can transmit high power using two channels(only for example) from fiber and attach spectrum analyzer at just after MUX and after SMF.You will notice the 2 another peaks appeared ,that is your FWM and you can measure power of side peaks from scale or by selecting the markers.I have given link from optisystem example explaining this.
      For SPM you can also go to the link given below and explaining the concept of SPM as
      A pulse propagating through a nonlinear medium undergoes a self-frequency shift due to self-phase modulation. The front of the pulse is shifted to lower frequencies, the back to higher frequencies. In the centre of the pulse the frequency shift is approximately linear.

      Validation of FWM Effect

      SPM-Induced Spectral Broadening


      https://www.furukawa.co.jp/review/fr019/fr19_12.pdf

    • July 16, 2015 at 1:02 am #22487
      Ashu verma
      Participant

      In order to switch off the non lineaer effects
      Go to optical fiber >non linear tab and deselect self phase modulation.

    • July 17, 2015 at 5:22 pm #22530
      Saja Al Mamoori
      Participant

      I need to design a WDM network where I have 4 channels to test the effect of fiber nonlinearities (XPM, FWM, and SRS) on adjacent and next adjacent channels. I am not interested in (SPM, SBS) as my project should consider multi-channel WDM network, not the effects on the same signal. I need to have results where I can plot a graph for XPM, FWM, or SRS change with channel spacing. Which components I have to us?

    • July 18, 2015 at 3:28 am #22534
      Ashu verma
      Participant

      Hello saja,you can study FWm and SPM easily in optisystem using different spacings.what problem you are facing.FwM csn be clearly seen from optical spectrum analyzer and you can also analyze the effect of frequency spacing.can you attach a system for better help? There are many research articles on fwm and spm in which fwm measured using optisystem.if you want that papers then let me know

    • July 18, 2015 at 5:59 pm #22538
      Saja Al Mamoori
      Participant

      Thank you very much Sam Sung for your replies. I have designed my networks as in the attached file like the sample of [FWM validation], I’ve added 2 more channels so now 4 channels entering the MUX. Channels frequencies are in THz (193.0, 193.1, 193.2, and 193.3). I got the result of optical spectrum analyzer before and after entering the fiber as shown in the attached files. I am new in this filed so I’m not sure how to analyze the results. I see new lines with some signals in the before file and then 2 lines with channels 193.2 and 193.3. Is this FWM signals, how can I change the channel spacing value? I tried to save the design as new project but

    • July 18, 2015 at 8:40 pm #22544
      Taiwo Ambali Abiola
      Participant

      As for changing the channel spacing value, all you need to do is to change the frequency of your CW light sources. For instance, the channel spacing in the one you have just designed is 100GHz. if you want to make it 50GHz spacing, your second CW laser would be 193.05 THz, the third 193.1, and the fourth is 193.15 THz etc. That means the channel spacing with the available channels is 50GHz. etc. I hope this is beneficial.

    • July 19, 2015 at 12:33 am #22547
      Ravil
      Participant

      Hi Saja,

      As I can notice from your attached pictures, you can see the cross-talk effects (i.e., FWM). However, since the level of your signal at the entrance of fiber is very low (about -50 dBm according to your pictures), it will be hard to differentiate clearly the non-linearities that you can have. At the same time, it will be very hard to detect such a low signal at the receiver. By the way, what non-linear coefficient do you consider for your fiber?

    • July 19, 2015 at 6:04 am #22554
      Ashu verma
      Participant

      Thank you saja
      I think you input power is low to observe the FWM effects clearly.increase your laser power on each cw laser and as taiwo said you can decrease the channel spacings.But your cw laser freq. Should be matched to wdm mux in order to get the desired output.Every time you change the spacings ,you will have to match it with mux.you can increase the value of gamma to increase the non linear efferctsthat depends upon effective area and non linear coefficient of fiber.you can get help from some research articles on the same topic,there are many articles on this particuler topic that i have studied.illet me know if you will need that.

      • July 19, 2015 at 9:57 am #22558
        Saja Al Mamoori
        Participant

        Thank you very much for these valuable information. Yes please send me the articles. Also I need to investigate the XPM and SRS on the same project, what do I have to change? and I need to know which one is the dominant effect, is it XPM? I have read that SRS depends on high power signals and my research is on high power jamming signals that causes distortion to other signals and may lead to service disruption. I used 0 dB power signals in my last project.

    • July 19, 2015 at 6:09 am #22555
      Ashu verma
      Participant

      Study this paper on channel spacing effects on FWM

      http://googleweblight.com/?lite_url=http://www.sciencedirect.com/science/article/pii/S0030402611001951&ei=vsSzRX1j&lc=en-IN&s=1&m=279&ts=1437300373&sig=AKQ9UO-ok3EU-Dt_bTdfyuM41rdGY6276gn

      • July 19, 2015 at 7:08 pm #22562
        Saja Al Mamoori
        Participant

        Thanks Samsung, is there any article that investigate the XPM effect with channel spacing?

        Best,
        Saja

    • July 19, 2015 at 6:37 pm #22560
      Taiwo Ambali Abiola
      Participant

      Thanks Samsung for sharing the material

    • July 20, 2015 at 6:00 am #22569
      Ashu verma
      Participant

      Hi saja ,find the link for xpm vs channel spacing article
      http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=4814224&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Farnumber%3D4814224

      http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=5431622&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Farnumber%3D5431622

    • July 20, 2015 at 10:03 am #22585
      Ashu verma
      Participant

      Welcome Taiwo

    • April 5, 2017 at 1:47 am #42932
      shivakumar rjgr
      Participant

      hi everyone, i have got the values of FWM in a wdm system and i want to check whether the obtained results are correct or not. please help me how to validate the results. i want to compare fwm of rz and nrz wdm systems

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