daniel.sigg@LIGO.ORG - posted 09:10, Tuesday 27 November 2018 - last comment - 09:19, Tuesday 27 November 2018(45518)
Squeezer laser found multimode (again)
Yesterday morning we encountered another instance where the squeezer laser has gone multi mode, similar to alog 45055. It does look like the diode current was turned to the max by an unknown person. Not sure, if we need to install the spare, but this laser seems particular susceptible to multi mode operation. Please avoid changing the diode current, and if you do, please log.
Here's a screenshot from ndscope. The laser was switched back on and stayed at the right current setting for about 2 hours before it jumped to the new current setting that caused multimode. The current setting (as of yesterday) that works isn't where it used to be either.
Current = 2.122, Temperature = 27.63 (as seen on the controller box)
This multimode was probably the cause of low seed power seen in alog45474.