Figure 2
From: Transmission estimation at the quantum Cramér-Rao bound with macroscopic quantum light
Measured signal and noise for T=15%, as a function of the transmission modulation amplitude. The signal trace (blue), obtained while ramping the modulation amplitude, and the optimized intensity-difference noise trace (red), obtained with the modulation off, measured with a spectrum analyzer are shown in volts on the left y-axis after subtraction of the electronic noise. The right y-axis shows the corresponding SNR obtained by taking the ratio of the signal to the mean value of the optimized intensity-difference noise. The value on the x-axis at which the signal is equal to the noise (or SNR = 1), marked by a circled “X”, gives the transmission modulation amplitude, \(\delta _{T}\), that can then be used to obtain the uncertainty in the estimation of transmission, \(\langle \Delta ^{2}T \rangle \), for the bTMSS (see Appendix A.3).