Following up on alog 48717 that shows that the projected frequency noise in DARM is limited by the IMC shot and dark noise above 2-3 kHz.

The modulation index is 12.5 mrad for the 24 MHz phase modulation according to alog 41889.

If we install a shutter for protection, we should be able to increase the power on the IMC REFL photodetector by up to 10. On the other hand, we can increase the modulation index by 16 before we are doubling the reflected power during lock. However, the later is hampered by the fact that the 24 and 45 MHz modulation share the same electrode on the EOM. The 24 MHz is off resonance and we are already driving it pretty hard.