Posting the LHO correlated noise budgets, including one time during squeezing, similar to LLO alog 44882.

The first plot directly compares DARM and the correlated noise during three times during and after O3.
The next three are the correlated noise budgets made for each time.


One key is we see a dip in the correlated noise with squeezing at ~150 Hz, the same frequency as LLO (in this plot).  This is due to the interaction of the squeezed light and the classical noise, as Yanbei explains in the LLO thread.  We see another dip at HF where laser intensity noise again contributes significant classical noise.  

Another key is that "mystery correlated noise" at 1 kHz goes up between October 2019 and August 2020.  Unclear what the source of this noise is.


The three dates plotted here are:
gps_start = 1283317218    # September 5, 2020 05:00:00 UTC
gps_stop  = 1283346018    # September 5, 2020 13:00:00 UTC
averages = 57600
csd_date = 'September 2020 (with squeezing)'

gps_start = 1282730359          # August 29 2020 09:59:01
gps_stop  = 1282763937          # August 29 2020 19:18:39
averages = 67156
csd_date = 'August 2020'

gps_start = 1256380478          # October 2019
gps_stop = 1256390478
averages = 20000
csd_date = 'October 2019'

Other relevant alogs:
LHO alog 56942
LHO alog 56896
LHO alog 52387

EDIT: Attached .txt files for all traces in lho_correlated_noise_comparison.pdf