Learning Forum

[Alex Fiani]

Hello, in Lumerical Mode, there is a model for index pertubation, and Ansys' website describes the Soref and Bennet model to be the best for charge carriers in silicon. However, it seems like they only provide 4 of the 8 coefficients at 1550 nm:

Where can I get information on the other 4 coefficients?

Thanks

[Guilin Sun]

Actually you do not need to have your own data as the material data has them when you add a "index perturbation" and choose this model:

[Alex Fiani]

I noticed this, however it is confusing as the coefficients listed on the Ansys website do not match the ones provided in the software. Also, it would seem that changing the base material has no impact on the coefficients in the software, so I can't seem to find a good way to tell what these coefficients actually are.

[Guilin Sun]

I agree. The data is not theortically proven uniquely so discrpancy is known. You may use your own data, or use one set if you trust more than the other.

Those values are for Silicon only. For other base materials, you will need to find your own.

In general, if you know the material's parameters you can use the Drude model.

[Guilin Sun]

Update: the online article uses the data from their 1987 work. But the index pertubation uses the newest improved data for more wavelengths and dopings, which is better. We will modify the documentation later.  Of course as always, if you have yoyr own data you can modify the data.

Thank you!