Fig. 3: Temporal Talbot effect of bright and dark pulse trains on a chip.

a Schematic of the experimental setup. CW continuous wave, EDFA erbium-doped fibre amplifier, PC polarisation controller, OSC oscilloscope, OSA optical spectrum analyser. Temporal profiles of b the original 4-GHz bright pulse trains at pass-through mode operation and c the corresponding 2× Talbot self-image of 8-GHz. Solid curves denote the experimental data, and the dashed curves represent the corresponding theoretical predictions. d Spectra comparison of these two pulse trains. e–g The corresponding temporal and spectral profiles of the dark pulse train. In (b, c, e, f), the theoretical curves are plotted in dashed blue lines, and the experimental ones are illustrated in solid red lines. In (d and g), the 4-GHz spectra are in yellow, and the 8-GHz (Talbot) spectra are in blue. h Temporal profile versus the dissipated power on the first-stage interferometer, showing the two operations of the chip and the transition regions in between.