(a–c) Integrated mode-locking device structure composed by an chain of anapole nanolasers with increasing emission frequencies ω1,ω2,...,ωn within the amplification bandwidth of the In0.15Ga0.85As semiconductor. The structure is coupled via tapered junction into a nanowire channel. (b,c) Provide a graphical illustration of the mechanism of pulse generation in this structure. Each anapole acts as a nonlinear oscillator characterized by a different emission frequency ωn and phase ϕn. Due to nearest-neighbour interactions, anapoles tend to mutually lock their phases to the same value, generating a stable train of pulses in the channel waveguide. (d) The 3D volume mapping of the electromagnetic energy in the structure at steady state. (e,f) Intensity evolution inside the waveguide channel (blue line). The intensity is normalized to the intensity of the electromagnetic field inside the nanodisk. The system forms equispaced pulses with duration of 95 fs and period of 190 fs. The solid red line in e shows the theoretical prediction from the standard theory of mode locking. (g) Emission spectrum (solid blue line) superimposed to the semiconductor gain profile (dashed orange line) exhibiting the locking of two electromagnetic frequencies located on the edges of the semiconductor amplification band.