R&D (FilterCavity)
YuhangZhao - 00:24, Sunday 08 December 2019 (1916)
Measurement of loss and phase noise(SQZ and ASQZ @20191206)

Yuhang and Yaochin

Firstly, we checked the amplification of BAB with 60mW. The factor is around 30. While the characterization we did last year shows amplification of roughly 60.

Then we measured SQZ and ASQZ at different green power

Green power(mW)

OPO T (kOhm)

PLL-pol (MHz)

CC1 error signal pk-pk (mV)

CC2 demodulation phase (SQZ)

CC2 demodulation phase (ASQZ)

60mW

7.23

170

49.2

124

130

55mW

7.227

170

40

118

138

50mW

7.217

170

37.5

115

139

45mW

7.211

170

31.2

110

145

40mW

7.205

175

30.8

110

150

35mW

7.201

180

26.4

105

155

30mW

7.196

185

23.2

100

155

25mW

7.189

185

21.6

90

155

From the above data, loss is 25.1% and phase noise is 19.4mrad. The loss is consistent with Aritomi-san's result. While the phase noise is a bit reduced.

We also measured the CC2 phase noise. The measurement is done with a 40mW green power and 110deg CC2 demodulation phase. Then we got CC2 pk-pk 62.4mV. We use this for calibration and got a phase noise of 4.25mrad.

Images attached to this report
1916_20191207162401_sqzfit.png 1916_20191210120428_phasenoise.png