Photonics

Photonics

Positive gain in ring modulator

    • dubey
      Subscriber

      I am trying to plot transmission using ONA in interconnect for graphene integrated ring modulator. Please help me understand this graph, why the transmission is switching to positive value with the increase in the voltage.

    • Guilin Sun
      Ansys Employee

      It might indicate that there is gain in the system. Please check the component input data and make sure they are passive.

    • dubey
      Subscriber

      https://optics.ansys.com/hc/en-us/articles/360042322794-Ring-Modulator

      I am using the above example as reference. Could you please explain why we need to find  Delta_neff in step 4. Cant we use just neff data calculated from the mode solver?

      Thank you

    • Guilin Sun
      Ansys Employee

      What modification did you do for the script andsimulation file?

       

      Since you did not specify which file, I just tested the Step 5, withought changing anything:

      When you have more voltage points, make sure the raw data has that voltage. Otherwise, the data will be interpolated, and errors can happen.

      I also tested positive voltage and they worked well. Then I tested 1.5,2.5 and 3.5V and the result has no positive result.

      Please test/check the individual voltage and see if the data has gain.

    • dubey
      Subscriber

      I have replaced dneff table in modulator element by the one generated for integrated graphene layer. Also, I replaced active and passive waveguide as per my own structure but with same bent radius and wavelength range. I can share all three files if needed. I am using the CE table that was included in the table. 

      I am attaching the lasted graph. It seems that at -10 v it has some gain.

    • Guilin Sun
      Ansys Employee

      This indicates some data are wrong in your file. Please only simulate at -10v, and verify its data. Unfortunately we are not able to help for a specific issue other than general, and we are not allowed to download customer files in the forum.

    • dubey
      Subscriber

      Hi, Thank you for your comments!

      If I use table of neff in the example, I am getting a transmission curve without any gain (see attached graph), even at higher bias voltage. Although, the peak transmission loss is around -8dB only. Could please explain briefly why there is need to find complex dn eff results as a function of voltage in Delta_neff.txt. (step 4 line 6) in this example?. Is the result would be correct If I just use the neff value?

    • Guilin Sun
      Ansys Employee

      When the charges cause index change, it also introduces absorption. this is why the index pertubation is complex.

      It seems your device needs higher voltage to get large dB dip. Please careffully check your data.

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