~ 1 W laser light is now travelling, so please be careful !! Especially, the area between MCF chamber and IMC REFL table is the most dangerous, I think...
I increased the power of the outgoing light from PSL room from ~ 15 mW to ~ 850 mW (measured at the last part of PSL). PMC and IMC were successfully locked, and then light with power more than 0.5 W should be injected to the downstream of the interferometer (IFI, IMMT, PR2, and PR3).
What I did:
-- rotated HWP just after the laser light source to increase the power injected to PMC so that PMC trans went up from 1 to 20.
- To compensate the increased optical gain, "common gain" of the PMC length control servo was decreased from 6.0 dB to -16 dB.
- PSL Guardian was editted correspondingly. Now PSL Guadian has two branches, one is for the low (previous) power and the other is for the high (current) power. Auto lock of PMC for the high power has been tested, but auto lock for the low power has not been tested yet.
-- rotated HWP after PMC to maximize the power of the outgoing light.
- A 5 % ND filter was inserted in front of the RF PD for IMC_REFL to prevent the saturation.
- "Common gain" of the IMC length control servo was decreased from -5 dB to -16 dB.
- IMC trans went up from 0.045 (0.020 corresponds to "no light") to 1.46 (~ 60 times larger).
- IMC_LOCK Guardian was editted correspondingly. Now IMC_LOCK Guadian has two branches, one is for low (previous) power and the other is for high (current) power. Auto lock of IMC for the high power has been tested, but auto lock for the low power has not been tested yet.
What remains to be done:
-- put appropriate ND filters in front of PMC_TRANS camera and IMC_REFL camera (I will do it tomorrow with a help of Keiko).
-- test Guardian for the low power (optional, not urgent).
