SPI, Optical Power Budget and SPI Prep Monitor Channels

J. Freed, J. Kissel, J, Wright, 

To take power measuments we used 2 different power meters a thorlabs Silicon S121C and Thermal S405C.

We are comparing these values to our optical power budget E2400441 

Optical Power measured in the installed SPI pathfinder

Location	Silicon (mW)	Thermal (mW)	Budget Est. (mw)
PSL IN port of SPI prep	178	157	149
Fiber Feedthrough Meas	64.0	57.6	53.4
Fiber Feedthrough Ref	18.3	16.1	21.2
In vac input meas	64.0	--	48.0
In vac input ref	15.0	--	19.0
POW PD Meas	1.0	--	1.1
POW PD Ref	1.1	--	1.4
After Periscope Entrence	42.0	--	40.0
Before Periscope return	21.4	--	20.0

These values agree with our budget. The input power is greater than we expected. The meas power has less losses than expected. While speciffically the ref path has more losses than expected. But not expected to be a problem. The uncertainty for all values was 1.0 except the values below 10 which were 0.1

We also recorded the values for the monitor channel from SPI prep at the same time. (the 5 values below were recorded at the same time)

M1= 7.62V

M2 = 758mV

M3 = 784mV

Ref (thermal) = 16.05mW

Meas (Silion)  = 64mW

Of course the 2W amp was just turned on so its gain fluctuates a little untill it is thermalized so we recoded all 5 values again once the 2W amp was thermaized

M1= 7.63V

M2 = 764mV (thermalized)

M3 = 788mV (thermalized)

MEAS (thermal) = 57.6mW

REF (Silion)  = 18.3mW