Fig. 1. Schematic model of a temporal-filtering dissipative soliton in an OPO.

Fig. 2. Numerical simulation results of a temporal-filtering dissipative soliton in the OPO. (a) Schematic of temporal-gain filtering and pulse chirp traces under different intracavity dispersions. (b) Spectra of dissipative solitons under different intracavity dispersions. (c) Pulse duration after compression versus intracavity dispersion. (d) Pulse peak power after compression versus intracavity dispersion.

Fig. 3. Experimental setup of the temporal-filtering dissipative soliton OPO. MOPA, Yb-fiber-based main oscillator power amplifier; HWP, half-wave plate; ISO, isolator; F1, plano-convex lens with a focal length of 300 mm; M1, M2, plano-concave mirrors with the same radius of curvature of 300 mm; M3, M4, plano-concave mirrors with the same radius of curvature of 100 mm; M5, plano-plano mirror. M1, M2, M3, M4 and M5 have a high reflectivity of more than 99.5% from 2.05 to 2.6 μm. OC, output coupler with a transmission of 3%. MgO:PPLN-1, MgO:PPLN-2 and ZnSe crystals are coated with a high transmission of more than 99.5% from 2.05 to 2.6 μm. The group velocity dispersions of ZnSe and MgO:PPLN are approximately 250 and −91 fs²/mm at 2.2 μm, respectively.

Fig. 4. Experimental results of temporal-filtering dissipative soliton in an OPO. (a) Dissipative soliton spectra under different intracavity dispersions. (b) Autocorrelation traces of the output pulses before (red line) and after (blue line) compression when the intracavity dispersion is 589 fs². (c) Pulse duration after compression versus intracavity dispersion. (d) Pulse peak power after compression versus intracavity dispersion. The data are recorded at an average output power of 1.5 W.

Fig. 5. Output results of the OPO for four different combinations of positive/negative nonlinear phase shift and normal/anomalous dispersion. Black line, spectra of the idler; red dash line, autocorrelation traces of pulses before compression; red solid line, autocorrelation traces of pulses after compression; Δk, wavevector mismatch of the SHG process of the idler; Δφ^NL, single-pass nonlinear phase shift; GDD, net intracavity dispersion. (a), (c) Dissipative solitons. (b), (d) Collapsed solitons. In the OPO setup, the polarization periods of MgO:PPLN-2 are selected to be 31 μm for (a) and (b) and 36 μm for (c) and (d) to provide positive and negative nonlinear phase shifts, respectively. The length of the ZnSe crystal is set to 4 mm for (a) and (d) and no ZnSe crystal is inserted for (b) and (c) to realize normal and anomalous intracavity dispersions, respectively.