Power Stabilization: Calculation and Outiline

Now I have put all the components (see last outiline) in the bench. I
have need of two mechanical parts (Roberto is doing them) for the
Photodiodes.

In order to comments of Alessio, I Think of modify the outline of study of stabilization in Power.



In this condition we have:
- Riflettivity of Beam Splitter (BS) (order 1) is around 16 %, but concering that the efficiency must to be around 5 %, we can remove the BS and to use one mirror. The Power on order 1 will be around 600 mW.
- Riflettivity of BSs (order 0) is around 13,4 % (BS 1) and 13,8 % (BS 2). With the efficienty around 5 % the power on order 0 is around 11 W, So the power on the photodiode will be 1,5 W and 1,3 W. The maximum power on the photodiode (opticaly immersed) is around 3,2 W, in other case is around 16 W. The problem perhaps can be the saturation of the amplifier...We can use the BSs that i just mount or to use BS of riflettivity around 5 %.

I think of use BSs of Riflettivity around 5 %...

Maurizio, if I understand well, you plan to use OI PDs in the intensity stabilization loop. Is is right? Actually, these PDs have very low power saturation level (few mW). The PDs would saturate long before the pre-amplifier is saturating!!! I think it is better to use the non-optically immersed PDs, since they have higher power saturation level (circa 1W).

Well, I will use (order 0) the not optically immersed PDs with BSs to 5 % of riflettivity.

I think that don't use the mirror for order 1 beam but use the BS that i have just mount...the power will be around 30 mW.

The BSs of the order 0 have a riflettivity of 3,2 %. The BS of the order 1 has a riflettiviry of 16 %.

From the scheme, it seems that you want to put the waveplate and the polarizer after the AOM. If the AOM is introducing some depolarization, power control may not work properly. I think you could remove the waveplate and polarizer and work at costant power.

I have put the waveplate and polarizer in input to the AOM. There is one error in the outiline,Sorry...New outline:



I put waveplate and polarizer for have the possibility of change the power if we want some measure on the photodiodes (for example Volt vs Power).

We can also remove them.