All-optical switching of ultrafast solitons at 1560 nm in dual-core fibers with high contrast of refractive index

•Study of solitonic all-optical switching in the C-band using dual-core fibers.•High index contrast all-solid soft glass dual-core fibers with improved symmetry.•4.5 dB switching contrast for 75 fs pulses between energy levels 200–700 pJ.•The fiber asymmetry allowed the switching only when the fast core was excited.•The numerical study confirmed the solitonic character and the experimental outcomes.