[Ushiba]
Today, I measured MN/PF OpLev laser power just after fiber collimeters.
Since our new laser sources have a display which shows current laser power, we can estimate the transmissivity of fibers from this measurement.
Following table shows the results (attached figure shows the plot of following results).
| displaed power | laser for MNL | laser for MNT | laser for MNV | laser for PFL |
| 0.5 mW | 0.366 mW | 0.387 mW | 0.294 mW | 0.422 mW |
| 1.0 mW | 0.715 mW | 0.729 mW | 0.535 mW | 0.802 mW |
| 1.5 mW | 1.02 mW | 1.09 mW | 0.785 mW | 1.20 mW |
| 2.0 mW | 1.42 mW | 1.45 mW | 1.05mW | 1.60 mW |
| 2.5 mW | 1.74 mW | 1.82 mW | 1.31 mW | 2.02 mW |
By linear fitting these results, transmittivities of each fibers and collimeters can be estimated as follows:
| laser for MNL | laser for MNT | laser for MNV | laser for PFL | |
| Transmissivity | 0.70 | 0.72 | 0.52 | 0.80 |
Transmissivity is not close to 1 and large variation.
I am not sure exact reason but probably it is due to the difference of core size of laser fiber and fiber collimeter.
However, transmitted laser power is over 1 mW and it is enough large to use it for OpLev light source.
So, this doesn't seem large issues.
