At first I checked the power of linear polarization (after HWP+QWP) which is incident on EOM. The measurement in oscilloscope of Moku showed 500Vp-p. This is the input power.

Then the photodiode measured the power after EOM in cross polarizer configuration. This was the output power.'

I apply voltage from 0-2Vp-p using Moku to the Opamp circuit. I then obtain the following plot (Fig 1) of Transmission % vs. Voltage. The data is saved in "Characteristics_20250217.txt".

The frequency of the RF circuit was identified by taking In1(from photodiode)/Out1(Input to the RF circuit). I measured the place of resonant frequency using laser.

Interpretation:

That result means the fitting routine found the parameters:

y = 112.8 sin(0.5x+0.5)**2 - 21.4 by using the fit function: A sin (Bx + C) **2 + D

which implies:

• Amplitude: 112.8, so the sin^2 term varies by 112.8.

• Frequency: 0.5, meaning the period is $\mathrm{T\; =\; 2pi/0.5\; =\; 12.57}$

• Phase shift: 0.5, so the sine's argument is shifted.

• Offset: -21.4, which makes the minimum value y_{min}=-21.4 (since ${\mathrm{ sin**2 }}^{}$goes from 0 to 1, the output ranges from 112.8-21.4=91.4).