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Message ID: 62     Entry time: Tue Jan 12 10:44:57 2021
 Author: Ronic Chiche 
 Status: Fixed 
 Type: issue 
 Category: lasers and optics 
 Location: Optical room 
 Title: Origami SN2440 133MHz laser power measurment... and failure 

we received from NKT the Origami SN2440 133MHz oscillator from repair on 2020/12/17
and we measured the power trend from 2020/12/21 until the whole winter Hollyday, during 14 days and 17h (1 273 334 s).
the power was quite constant, about 58mW (the measurement has been done with the OD2 filter and using a (x20) factor in the software to compensate for it),
except for some peaks at the beginning of the measurement to 60.7mW.
I tried to reproduce these peaks by switching on several lights in the room and the airflow ceil but the effect is neglectable,
thus these peaks seem to really come from the oscillator power.

at the beginning of January, the oscillator suffered a back reflection from the rugged anodized convex surface of the power meter (apparently not from the OD2 filter itself) and the laser stopped immediately to modelock.
the laser power dropped to 0 and the laser controller led started to blink red. NKT has been contacted and they think it could be the laser pump diodes that have been damaged.

for the future, we will have to install a fixed optical isolator from the start, even for short operations.

 

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133mhzpower.PNG
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