[Aritomi, Eleonora, Matteo, Yuhang]

 

Today we measured first squeezing at 200 kHz.

 

Attached figure shows time series of shot noise of LO at 200 kHz with and without squeezing.

Shot noise level with squeezing modulates when relative phase between LO and squeezing is modulated.

Measured squeezing level is about 4 dB and anti squeezing level is about 5 dB. 

 

Detail:

First we recovered mode matching of LO and BAB inside AMC. For LO, main peak is 2.24V and mode mismatch peak is 24mV, so mode matching is 2.24/(2.24+0.024) = 98.9%.

For BAB, main peak is 336mV and mode mismatch peak is 17.6mV, so mode matching is 336/(336+17.6) = 95%.

 

Then we measured visibility of LO and BAB. Maximum is 7.56 V and minimum is 1.56 V which means visibility is 65.8%.

Considering that LO is 528uW and BAB is 78 uW, the expected visibility is 67.0%. That means mode matching of LO and BAB is 98.2 %.

 

For measurement of squeezing, we injected 30mW green power into OPO which corresponds to 1/3 of OPO threshold. LO phase is modulated at 2 Hz with 900 mVpp.

The homodyne signal is amplified by 200. The data is taken by spectrum analyzer (E4411B ESA-L) with zero span mode whose center frequency is 200kHz, RBW is 1 kHz, sweep time is 2s.

 

Next steps:

- loss analysis of the system

- check the stability of the control systems

- measure the squeezing level at lower frequency 

- measure green power dependence of squeezing level

- coherent control

 

Today we measured first squeezing at 200 kHz.

Attached figure shows shot noise of LO with and without squeezing.

Shot noise level with squeezing modulates when relative phase between LO and green pump is modulated.

Squeezing level is about 4 dB and anti squeezing level is about 6 dB. 

 

Detail:

First we recovered mode matching of LO and BAB inside AMC. For LO, main peak is 2.24V and mode mismatch peak is 24mV, so mode matching is 2.24/(2.24+0.024) = 98.9%.

For BAB, main peak is 336mV and mode mismatch peak is 17.6mV, so mode matching is 336/(336+17.6) = 95%.

 

Then we measured visibility of LO and BAB. Maximum is 7.56 V and minimum is 1.56 V which means visibility is 65.8%. Considering that LO is 528uW and BAB is 78 uW, the expected visibility is 67.0%. That means mode matching of LO and BAB is 98.2 %.

 

For measurement of squeezing, we injected 30mW green power into OPO. LO phase is modulated at 2 Hz with 900 mVpp. The data is taken by spectrum analyzer with zero span mode whose center frequency is 200kHz, RBW is 1 kHz, sweep time is 2s.

 

Next step:

loss analysis of the system

check the stability of the control system

measure the squeezing level at lower frequency 

measure green power dependence of squeezing level