Fig. 2: S-TAI amplification and recovery of spectral waveforms.
a, b The input waveform (black) is simultaneously amplified and sampled using the S-TAI (output shown in green). The input waveform scaled by the measured amplification factor is shown for comparison (dashed black trace). a The system was first configured for a high amplification factor of q = 32, with a peak separation νq = 44.8 GHz and a peak width νs = 1.4 GHz (see figure inset). The output waveform resulted in a measured amplification of 29.1 with νq = 44.4 GHz, and νs = 1.6 GHz. b To recover a more complicated waveform (i.e., with a longer duration), the temporal phase modulation signal was electronically reconfigured for q = 15, allowing for a higher spectral resolution with a peak separation νq = 30.1 GHz and a peak width νs = 2.0 GHz. The output waveform resulted in a measured amplification of 14.43 with νq = 30.3 GHz, and νs = 2.2 GHz. c A weak optical waveform (black, right axis) is combined with strong stochastic (ASE) noise (gray, left axis). Notice the significant difference in the vertical scales. d The waveform is completely buried under noise, becoming undetectable. e Using the same parameters as those in Fig. 2a, the waveform of interest is successfully recovered from noise (green, left axis), as indicated by η, a measure of the visibility of the waveform against the noise, see Eq. (3). The input (dashed black trace, right axis) is shown for comparison, confirming that the envelope of the S-TAI peaks outlines an amplified, high-fidelity copy of the input signal. All shown optical spectra are represented as a function of the relative frequency with respect to a center optical frequency of 193.470 THz (wavelength of 1549.56 nm) on a linear scale normalized to the average power of the input coherent waveform measured at the locations of the output peaks (see “Methods”).
