Warning: Undefined variable $s in /var/www/public_html/osl/classes/DAO.php on line 959
NAOJ GW Elog Logbook
LOG-IN
Displaying report 1-1 of 1.
R&D (FilterCavity)
Print this report.
NaokiAritomi - 22:21, Monday 11 November 2019 (1837)Get code to link to this report
Squeezing and anti squeezing measurement with new faraday

[Aritomi, Yaochin]

We measured squeezing and anti squeezing with new faraday to estimate loss and phase noise.

green power (mW) MZ offset OPO temperature (kOhm) p pol PLL (BAB) (MHz) BAB maximum (V) CC2 demodulation phase (SQZ) (deg) CC2 demodulation phase (ASQZ) (deg)
0   7.18 265 0.19    
20 4.1 7.17 190 0.888 85 165
25 4.19 7.16 160 1.09 85 165
30 4.29 7.18 180 1.46 90 160
35 4.38 7.18 175 2.12 100 155
40 4.5 7.19 180 3.04 110 155
45 4.58 7.19 170 3.68 115 150
50 4.68 7.19 160 4.72 120 150
55 4.78 7.2 165 6.24 125 145
60 4.88 7.2 160 7.68 130 140
65 4.98 7.2 160 10.1    

Attached picture shows the result. Loss is 25.4% and phase noise is 21.4 mrad. Compared with previous measurement, we have 4.5% more loss. We should have 3% more loss from faraday and HWP, but we should have ~3% less loss from dichroic mirror (entry 1613). So this 25.4% loss is higher than we expected. Maybe we have worse visibility after installation of faraday. We'll check visibility tomorrow.

If I remember correctly, after improving reflectivity of dichroic mirror, squeezing level didn't change. It is also better to check the reflectivity of dichroic mirror again.

Good news is that even though we turned on lasers today, we have only 21.4 mrad of phase noise and squeezing spectrum is very flat with new faraday.

Images attached to this report
1837_20191111142138_sqzasqz20191111.png