Fig. 1. Experimental setup. (a) Observation system of multisoliton complexes. The NPR-based mode-locked fiber laser outputs the multisoliton complexes, for which spectral and temporal observations are conducted. PC, polarization controller; EDF, erbium-doped fiber; LD, pump laser diode at 980 nm; WDM, wavelength division multiplexer; OC, optical coupler; SMF, single-mode fiber; SMF 1, 10 km; SMF 2, 250 m; SMF 3, 500 m; PD, photodiode detector; OSA, optical spectrum analyzer; MLFL, mode-locked fiber laser; HNLF, highly nonlinear fiber, 100 m; DCF, dispersion compensation fiber; DCF 1, 2.8 km; OSC, oscilloscope; BPF, bandpass filter; BPF 1, centered at 1590 nm; BPF 2, centered at 1570 nm; BPF 3, centered at 1550 nm. (b) Structure of the pump cavity. TDL, time delay line; DCF 2, 0.8 m. (c) Temporal series of the under-test multisoliton complexes recorded by the oscilloscope. (d) Temporal series of the pump pulses. (e) Spectrum of the pump light.

Fig. 2. Temporal-spectral retrieval facilitates the unveiling of molecular assembly. (a) Temporal-spectral retrieval of multisoliton complexes. (b) Isomeric dynamics of multisoliton complexes.

Fig. 3. Temporal-spectral analysis of soliton triplets. (a) Graphical representation of the unequally spaced soliton triplet. (b) Interferogram of the soliton triplet obtained by the OSA. (c) Consecutive interferograms of soliton triplets with 2000 roundtrips obtained by DFT. (d) 2D contour plot of the AC traces for 2000 roundtrips. (e) AC trace of the soliton triplet. (f) Temporal reconstruction via the time-lens acquisition. (g) Energy and separation analysis. The red curve showcases the total intensity of soliton triplets and the blue curves present relative separations.

Fig. 4. Isomeric assemblies of soliton quartets. (a) Temporal waveform of equally spaced soliton quartets. (b) Interferograms and (c) AC trace of the equally spaced soliton quartets. (d)–(f) (2 + 2) soliton quartets. (g)–(i) (3 + 1) soliton quartets. (j)–(l) (2 + 1 + 1) soliton quartets.

Fig. 5. Energy exchange in the evolving (3 + 1) quartets. (a) Conceptual diagram of intramolecular energy exchange within the (3 + 1) soliton quartets. (b) Consecutive interferograms obtained by the DFT technique. (c) Relative phases from the first, the second, and the third pulses to the fourth pulse. (d) Temporal reconstruction of (3 + 1) soliton quartets by the time lens. (e) Energy analysis of the evolving soliton quartets. (f) Temporal waveforms of soliton quartets of roundtrips 4620, 4720, 4820, …, 5720.

Fig. 6. Numerical simulation of the isomeric assemblies. (a) (2 + 1 + 1) soliton quartets. (b) (1 + 2 + 1) soliton quartets. (c) (1 + 1 + 2) soliton quartets. (d) (3 + 1) soliton quartets.

Fig. 7. Numerical simulation of the energy exchange. (a) Real-time interferograms of (3 + 1) soliton quartets. (b) Phase analysis and (c) pulse intensity of the (3 + 1) soliton quartets. (d) Real-time interferograms of (1 + 2 + 1) soliton quartets. (e) Phase analysis and (f) pulse intensity of the (1 + 2 + 1) soliton quartets.

Fig. 8. (a) Spectra of the soliton pair; (b) consecutive interferograms of soliton pairs with 2000 roundtrips; (c) 2D contour plot of the AC traces for 2000 roundtrips, showing the binding separation is 17.39 ps.

Fig. 9. (a) Spectra after the HNLF. It consists of three wavelength components, in which the signal light is centered at about 1590 nm, the pump light is centered at about 1570 nm, and the idle light generated via the FWM effect is centered at about 1550 nm. (b) The temporal waveform of the soliton pairs after magnification via the time lens. (c) The curve of magnified separations of soliton pairs.

Fig. 10. (a) Temporal waveforms of five-pulse complexes recorded by the time lens. (b) Temporal waveforms of six-pulse complexes recorded by the time lens.