Real-time revealing of Cherenkov radiation evolution in optical fibers

The generation of Cherenkov radiation (CR) is determined by the phase-matching condition, but the experimental observation on the phase change of its transient process is still incomplete. In this paper, we use the dispersive temporal interferometer (DTI) technique to real-time reveal the buildup and evolution of CR. Experiments show that when the pump power varies, the phase-matching conditions also change, which is mainly affected by the nonlinear phase shift caused by the Kerr effect. Further simulation results propose that both pulse power and pre-chirp management have a significant impact on phase-matching. The CR wavelength can be shortened and the generation position can be moved forward by adding a suitable positive chirp or increasing the incident peak power. Our work directly reveals the evolution of CR in optical fibers and provides a method for optimizing it.