March 19, 2024 at 9:57 pm

GWANG

Ansys Employee

Hi Mohamed Selim,

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Thank you for the feedback. I have elevated this up, and I got some comments from our R&D team:

- Equation 27 is wrong. I have updated the page and the length should have a sqrt. Here is the updated equation:
- The input parameter for PMD is the PMD coefficient, Dp, as in equation (26). Then the PMD differential group delay is calculated using eq (27).Â The differential group delay parameter is an user input additional delay that the user can use. Its not used in the delay calculated by equation 27 from PMD. You can see that its independent whether you enable PMD or not. More specificly, there are two differential group delays: One is the input parameter, this is an independent delay that the user can set whether PMD is enabled or not. There is another delay, not input parameter, that is calculated from the PMD coefficient as in eq 27 and is called deltaBetaPMD. Therefore you should only set the PMD coefficient and the PMD delay will be calculated according to eq(27). In addition you should set the differential group delay to 0.Â

Hope this now is clear.Â