Ultrafast All-Optical Two-Colour Switching in Asymmetric Dual-Core Fibre

Dual-core optical fibres (DCFs) represent devices for a simple ultrafast all-optical signal processing, in particular for cross-switching tasks [1] , [2] . Recently, we have developed a highly nonlinear, all-solid DCF, scanning electron micrograph (SEM) of which is shown in inset of Fig. 1a ). High contrast of refractive index of the DCF enabled the efficient self-switching of the femtosecond solitons in the C-band at sub-nJ switching pulse energies [3] . Here, we present an improved approach: using the same DCF with a slight dual-core (DC) asymmetry, we perform a two-colour control-signal switching. This permits to achieve higher switching contrast and preserves better pulse shape.