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Wed May 13 16:57:28 2009, Dmass, Laser, PMC, Relocking the PMC
Thu May 14 20:57:22 2009, rana, Laser, PMC, Relocking the PMC
Fri May 15 04:23:19 2009, Dmass, Laser, PMC, Relocking the PMC
Thu May 14 20:57:22 2009
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Relocking the PMC
Instead of using the polarizer all the way, set the polarizer to transmit a few W and then use a fixed BS to attenuate down to 10-30 mW before doing the PMC alignment.
The ZAD-6 is a level 7 mixer so you have to give it 7 dBm. So there should be no attenuator after the splitter for the LO.
Have to AC couple (or DC block) the PDA signal before going into the mixer. It wants AC only.
The mixer output should go into the 1.9 MHz low pass and then get terminated with 50 Ohms (like with a T). Then the other output of the T can go to the DAQ or into the SR560 for some gain but you shouldn't need very much gain. Certainly the SR560 should have no filter clicked on.
If you use the SR560, make sure the output is zero with no light on the PD. There's a trim pot on the front.
In the digital world there should be a single pole around 1 Hz. Make sure the output actually goes to the PZT driver.