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To help us solve your issue as quickly as possible, please provide the following information:
1. What device are you trying to simulate? Include diagrams if available.
Laser with a taper Si waveguide underneath to couple light from laser to silicon platform
2. What results are you trying to obtain? Be as specific as possible.
Transmission efficiency (S21^2)
3. Description of the problem or issue.
The tapered Si waveguide can be divided into three part: width (1) increases linearly at the input, (2) keeps the same in the middle, and (3) decreases linearly at the output. And I used to set one cell group for the whole structure, as below.
set(“number of cell groups”,1);
set(“group spans”,xw2); #xw2=the total length of the structure
I’m wondering if the S21^2 I got is wrong for my setup, because the S21^2 is different from the one obtained from 3 cell groups. Is the setup of 3 cell groups necessary to get the correct S21^2?
Thank you for your help!
4. Lumerical product and software version.
Lumerical 2019b MODE
5. Please attach your simulation files, including any logs.