The expected beam diameter for our case is calculated like this:

D = 4*lambda(1064nm)*f(11mm)/(pi*MFD(6.2um)) = 2.4mm

We also received some suggestions from Tomura-san,

1. Check to meet the NA's requirement. (Tomura-san told us basically that is all)

        NA of lens: lambda/(pi*(MFD/2)) = 0.11

        NA of fiber(HI-1060-Flex): 0.14 (from manual)

   From this point of view, we are fine.

2. He also thinks we need to notice if we damage the fiber, if we bend it too much. Our complicated collimator (more complicated than Tomura-san's) can make couple more difficult.