It turned out that the power normalization need a modification.
I will work on it tomorrow and it will take approximately 2 hours to finish the modification.
Concept of Power Normalization
Koji pointed out that the dynamic power normalization, which I have installed( #6156), should be placed after the LSC input matrix rather than before the matrix. Now let us review the concept of the power normalization to avoid some confusions.
We will need two kinds of power normalizations as follows:
- Static power normalization, which should be placed before the input matrix.
- Dynamic power normalization, which should be placed after the input matrix.
The static power normalization will be applied to each I and Q signals in all the LSC signals and also DCPD signals.
This normalization is supposed to cancel the effects from the incident laser power and depths of the phase modulations.
Because the variations in the laser power and modulation depth are expected to be relatively slow, we will apply static normalizations.
The dynamic power normalization will be applied to the DOFs error signals, for example C1:LSC-DARM_IN and so on.
This normalization is supposed to cancel the effect of the internal states of the interferometer, for example alignments.
In addition to it, this dynamic normalization can expand the linear range of the error signals.
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Now a power normalization is doable for the LSC error signals.
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