I measured dark noise of the beatnote detector reaching moku and its effect on measured beatnote frequency noise.

Measurement

• I used Andrew's low noise preamplifier to measure this noise.
  
• I first took the transfer function through the preamplifier so that everything later can be referenced back to its input.
• I measured measurement setup noise by shorting the input to the pre-amplifier.
• Then I measured dark noise after the 20 dB coupler (the cable that I connect to moku) when the detector was completely blocked with a beam dump.
• The noise was converted to precieved beatntoe frequency noise by using peak to peak voltage of beatnote signal. (Noise*freq*2*pi/Vsigpkpk)
• The noise came a little less than Tara's measurement. I'm updating my noise budget model with this now.

Data