Hi Zemaxers

 I am reading this tutorial, and the NA in System and Fiber coupling confused me

https://optics.ansys.com/hc/en-us/articles/42661821960851-How-to-model-angle-cleaved-fibers

As far as I know, the fiber coupling efficiency does not use the system NA to calculate, but you need to input in the its own

And I am just wondering, why the two NA do not match? say, both NA 0.2 or NA 0.1

the tutorial shows a setup like

obj- lens- image

simulates  source fiber - lens - receiver fiber 

so shall the light source NA = source fiber?  

it will be appreciated if you point out my misunderstanding 

thank you

Yang