Why 3dB bandwidth keep the same as the detector length (Ge length) increase?

zhenjiehanzhenjiehan Member Posts: 18
edited May 28 in Photonics

Dear lumerical support,

When I increase photodetector length(Ge length) from 5um to 50 um, I found performance behave normally except for 3dB bandwidth, which remain the same, which isconflict with what it should be.

The performance calculated is shown below.

I really want to know what happened.

The simulation profile of 3dB bandwidth for length 5um and 30um is in attchment.

I really wish to get help from you!

Best regrads!


  • greg_baethgegreg_baethge Posts: 121Ansys Employee

    Hi @zhenjiehan,

    Thank you for your post. I'm not allowed to check your files, but I was wondering, did you change the normalization length in the CHARGE simulation?

    This parameter is what will define the length of the device since we only run a 2D simulation.

  • zhenjiehanzhenjiehan Posts: 33Member

    Hi.@greg_baethge ,

    Thank you for your respond. Acturally, I have checked the normalization length in device simulation. They are displayed correctly.

    What else could cause this situation?

    Can I send the file to you via Baidu Cloud Disk? Can you receive files from Baidu Cloud Disk?

    Best regards!

  • greg_baethgegreg_baethge Posts: 121Ansys Employee

    Thanks for the additional information, @zhenjiehan. As I mentioned, Ansys employees are not allowed to download any file posted here (see this post), so I can't check your files. Could you give some further information on the flow you used to get the response of the PD for different lengths? Regarding the bandwidth, did you use the ssac and/or the transient simulation? If both, do they give the same results?

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