Tests around the fibers bringing the pump to the neoVAN

# we check whether that the swap of spare fiber FOPT-1801-01 with FOPT-1703-02 is mandatory
- with the fiber PSL-FOPT-1703-02 on the neoVAN, we get PMC_TRA = 66.0-66.7 W
- we install the fiber PSL-FOPT-1801-01 instead of PSL-FOPT-1703-02, we get PMC_TRA = 65,5 W
we come back with fiber PSL-FOPT-1703-02 on the neoVAN, we get PMC_TRA = 66.0 W

--> it seems both fibers are equivalent as long as some bending is put on PSL-FOPT-1703-02

# Fiber bending (for stress) location

we check whether the bending set near th eamplifier head is still mandatory while another bending has been set on the diode side

with stress near the head released: the power drops and comes back to 66 W
-> seems the stress becomes useless as long as another stress has been set near the diode box

Rem. : removing the stress on the fibers at the diode side give a drop of 1 W at the PMC output

-> it seems cumulative bending of the fiber does not bring any significative improvement. One single beding (one fiber turn over a 10 cm diameter round) seems enough