Well spotted! I have corrected issue #1 you noticed, a very silly mistake, thank you! #2 is great background! But these cosine losses are I suppose not a the

Well spotted! I have corrected issue #1 you noticed, a very silly mistake, thank you! #2 is great background! But these cosine losses are I suppose not a theoretical limit but a limitation of fibre optics so I won't include that (but I will link to your comment!).