How to calculate the confinement loss of the photonc crystal fiber

Hi,

I am using the RF module to do some calculations of fiber. And I don't know how to calculate the confinement loss in fiber. I found that some people said the PML will be used to do this on this forum. But I am still confused on how to add the PML and set the parameters. Is there someone who knows how to deal with this problem? Please give detail tutorial if possible. I will appreciate it a lot for this. Thanks.

Regards,
Zhengyong Liu