Fig. 1: Experimental demonstration of single-soliton Kerr combs in a MgF2 microresonator using the frequency-scanning method.
From: Advances in resonator-based Kerr frequency combs with high conversion efficiencies
a Experimental setup for DKS generation. b Transmission observed when scanning the CW laser over a resonance from the blue detuning to red detuning regime (green shading). Solitons are generated in the red detuning regime and then annihilated to form discrete steps in the further red detuning regime. The inset shows the Lorentzian resonance shape of the cold microresonator (dashed line) and the triangular resonance shape under the combined Kerr and thermal effects of the strongly driven microresonator (solid line). c Optical spectra of three different states (marked in (b)) for the CW laser scanning in the blue regime. d Optical spectra of Kerr combs with 2 and 1 solitons. The insets show the radio frequency beatnote. e Measured frequency-resolved optical gating (FROG) traces of the two-soliton and single-soliton pulses. f The reconstruction of power profile (the red dashed line with a sech2 shape) and phase (the yellow solid line) of pulse (top panel), and sampled optical power of the output over a duration of 40 ps (bottom panel) of the single-soliton pulses. OSA optical spectrum analyzer, ESA electrical spectrum analyzer, PD photodetector, LO local oscillator, FPC fiber polarization controller, EDFA erbium doped fiber amplifier. Images are adapted with permission from ref. 30. Copyright 2014 Springer Nature Limited.
