Extended Data Fig. 4: Extracting noise figure from SPF spectrum.
From: Low-power integrated optical amplification through second-harmonic resonance
(a) Signal and generated idler measured with the max-hold technique (circles), as well as spectrum for a single signal wavelength input (solid line). (b) Degenerate amplification spectra. SPF level is extracted from off-degenerate reading, and the gain is extracted not from this single scan but instead by measuring the amplification/deamplification cycles in time as in Fig. 4(c).
