Testing RSOA modulation bandwidth?

[zsliu]

Dear all,

I am going to test the modulation bandwidth of RSOA. I upload the setup. the issue is that I cannot get 1GHz signal after PD when I use 1GHz sinewave to modulate RSOA.

Thanks

Attachments:

1. RSOA_BW_test.osd

[Damian Marek]

If you bias the Sine generator to 0.5 A.U. you will get the peak at 1 GHz.

[zsliu]

Hi, Damian,

as you suggested, i can detect the peak around frequency. now the problem is the modulation bandwidth unlike real RSOA which show us low pass property. any suggestion on that? thanks

Zhansheng

Attachments:

1. RSOA_BW_test_v2.osd

[Damian Marek]

In your particular example, I think the cutoff frequency is much higher than the values you swept. Try increasing the frequency to >10 GHz, I achieved a low pass filter shape. Although it was not perfectly flat.

Regards

[zsliu]

Thank you so much for your reply. The modulation bandwidth is generally less than 2GHz in a real RSOA component. the shape is going high from 100 MHz, may be increased by more than 5dB, then going to drop, even if I changed some parameters.

[Damian Marek]

OK then the problem is something else! Do you have a paper with the results you are expecting? Showing the cutoff frequency and containing information about the RSOA parameters.

[zsliu]

yes. please find the two attached documents. the curve in first file page14. the parameters are in the second file at page92.

[Damian Marek]

Hi Zsliu,

The OptiSystem team is determining whether the gain is a problem with the default parameters not corresponding to a peak gain at the default wavelength. For now can you please try the Linear or Lorentzian gain approximations for the material gain in the Enhanced tab.

Regards,
Damian

[zsliu]

Hi,Damian

I tried the linear gain approximations, which is generally used for bulk RSOAs. However, the results are not correct. I even cannot get sin waves . I haven’t figured out where the problem is. could you please help me?

Thanks

Attachments:

1. RSOA_BW_test_v3.osd

[Damian Marek]

I replaced some of the default parameters in the RSOA with those from the reference paper. (Active volume mainly)

I got a good sine wave response, let me know if this is closer!

Attachments:

1. RSOA_BW_test_v3_DM.osd

[zsliu]

Damian, thank you so much for helping me lots on the rsoa module. The modulation bandwidth is still so high, more than 6 GHz when I used the linear gain approximations. I tried to change some parameters. however I havent figured out. any suggestion?

[zsliu]

finally, I got the more reasonable modulation response. however the curve starts rising around 2.4GHz as shown in fig. some parameters may not be proper.

Attachments:

1. 

   response-scaled.jpg
   

[Damian Marek]

I think I used most of the parameters in the document you posted, you could also try the Lorentzian qpproximation. It is hard to say though since I only have one page to work from and it doesn’t say what type of model it is using. You can look at our help file which is accessed by the component properties window and see the background theory and references we use. You should be able to match the parameters with those from your reference.

Regards

[zsliu]

please find the files

Attachments:

1. 1.pdf

[zsliu]

sorry the second file is too large. I just extracted the corresponding page

Attachments:

1. 2.pdf

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