Figure 1, attached, shows the phase noise I measure from the 2 um Mach Zehnder interferometer. This phase noise is from the optical path and is affected by:
- Intensity noise.
- Laser frequency noise.
- Differential polarisation shifts through the IFO arms.
- Changes in differential arm length.
- Changes in refractive index.
- Detector noise, in which I am also grouping noise due to the amplifier.
The next step is to determine contributions from each of these sources.
Attachment 2 shows the setup used to measure this noise. Attachment 3 shows the measured phase spectra from both phasemeters of the Moku. Attachment 4 contains the both time series and spectra. The spectra shown here are:
- Converted to radians, from cycles.
- Subtracted, in time domain.
- Converted into power spectra, using Welch's method, 30 averages and Hanning windows.
- Converted into amplitude spectra, by taking the square root.
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