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Power recycled Michelson with arm cavities

by Jerome Degallaix — last modified 2014-01-16 10:07

Benchmark tests for the first phase of Advanced Virgo (i.e. without signal recycling)

That is the configuration of the Advanced Virgo from the end of 2015 up to 2017. For the simulations, we will look at three main quantities: the circulating power in the power recycling cavity (P_PRC), the circulating power in the arm cavities (P_arm), and the DC power at the dark port (P_DP).

We do not include the sidebands since this case has already been take care previously (see here).

The numbers given in table are all in W for 1W of input power.

The perfect case

With the nominal parameters, no defect.

Package	DarkF	FOG	OSCAR
P_PRC	36.9		36.9
P_arm	5175		5173
P_DP	1E-6		1E-6

One end mirror HR RoC wrong

Now RoC EM = 1690m (instead of 1683m)

Package	DarkF	FOG	OSCAR
P_PRC	36.6		36.6
P_arm	5134		5131
P_DP	0.01		0.01

With OSCAR that simulations is 2.6 times slower compared to the perfect case.

Same time with DarkF.

One input mirror HR RoC wrong

Now RoC IM HR = 1430m (instead of 1420m)

Package	DarkF	FOG	OSCAR
P_PRC	36.5		36.6
P_arm	5120		5135
P_DP	0.01		0.01

With OSCAR that simulations is 2.2 times slower compared to the perfect case.
Same time with DarkF.

One input mirror AR RoC wrong

Now RoC IM AR = 1430m (instead of 1420m)

Package	DarkF	FOG	OSCAR
P_PRC	36.9		36.9
P_arm	5175		5173
P_DP	1E-6		1E-6

(so not much change it seems)

PRM HR RoC wrong

Now RoC PRM HR = 1440m (instead of 1430m)

Package	DarkF	FOG	OSCAR
P_PRC	36.8		36.8
P_arm	5174		5152
P_DP	8.3E-7		8.5E-7

BS reflectivity imperfect

Reflection of the BS toward the West arm is 51% (instead of 50%), transmission in that case is 49% (no loss)

Package	DarkF	FOG	OSCAR
P_PRC	36.9		36.9
P_arm	5279 5072		5276 5269
P_DP	1E-6		1E-6

The two arms circulating power are given for the West and North arms

Imbalance loss in the arms

The round trip loss in the West arm is now 150 ppm instead of the usual 75 ppm.

Package	DarkF	FOG	OSCAR
P_PRC	29.9		28.4
P_arm	4149 4193		3950 3992
P_DP	8.2E-4		7.8E-4

The two arms circulating power are given for the West and North arms

Configuration

Number of points of the grid: 128 X 128

Size of the grid: 0.4 X 0.4 m

Diameter of the mirrors: 0.33 m (BS perfect and very large)

Arm cavity parameters can be found here, PRC parameters are there. POP and CP not included, set the PRC round trip loss to 2000 ppm.

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