[Aritomi, Yuhang]

 

Yesterday we measured squeezing and anti squeezing with s pol and good visibility (99.7%). We decided p pol PLL frequency in two ways. One is maximizing parametric gain of BAB transmission and another one is maximizing CC1 error signal. Since actual case is second case, we set p pol PLL frequency with second case. This time we adjusted demodulation phase of CC2 for squeezing and anti squeezing every time we changed green power. The result is as follows.

 

green power (mW)	MZ offset	OPO temperature (kOhm)	p pol PLL (BAB) (MHz)	p pol PLL (CC1) (MHz)	BAB maximum (V)	Demodulation phase of CC2 (SQZ) (deg)	Demodulation phase of CC2 (ASQZ) (deg)
0			315		0.114
15	4.01	7.16	190	190		30	100
20	4.1	7.16	175	175	0.54	30	100
25	4.19	7.16	165	160	0.704	30	100
30	4.29	7.17	157.5	165		35	90
35	4.38	7.17	162.5	160	1.34	48	90
40	4.5	7.18	165		2	50	80
45	4.58	7.19	175	150	2.92	50	80
50	4.68	7.19	162.5	155	4.08	53	75
55	4.78	7.2	167.5	155	5.52	58	75
60	4.88	7.2	160		7.12
65	4.98	7.2	155		9.04

Squeezing and anti squeezing plot is attached. The result seems more reasonable. We have 6.1dB squeezing with 40mW green! We estimated loss is 20.8% and phase noise is 26.3mrad. Given that loss between OPO and homodyne is ~8% and loss from homodyne (visibility, quantum efficiency) is ~ 3%, loss from OPO seems ~10% (design is 5%).

We decided p pol PLL frequency in two ways. One is maximizing parametric gain of BAB transmission and another one is maximizing CC1 error signal. Since actual case is second case, we set p pol PLL frequency with second case. This time we adjusted demodulation phase of CC2 for squeezing and anti squeezing every time we changed green power. The results is as follows.