Dear Sir/Madam

Just to analyse the effect of NA on direct light coupling and power coming out form a optical fiber, I am directly coupling light from a LED to optical fiber of core dia 734 um and cladding dia 750 um, by keeping the separation between LED and fiber almost zero to have more power copling at coupling end of fiber. 

For setting the NA of fiber I am using below data…

NA        Core R.I.     Cladding R.I.

0.5         1.45              1.361

0.4         1.45             1.3937

0.3         1.45             1.4186

0.2         1,45             1.437

My understading is, when I will increase the NA of fiber, power coming out from the fiber should increase! Because in that case less rays will leak to the cladding.

But In zemax simulation I getting exactly reverse (increase in NA is leading to decrease in output power). 

Where I am doing wrong? 

I am attaching .ZAR file.

Appreciate a comment!

Thanks