All-solid dual-core fiber design for dual-wavelength 1–2 µm control-signal switching of ultrafast pulses

This study optimizes a dual-core fiber (DCF) design for femtosecond nonlinear dual-wavelength switching applications at 1030 nm (control pulse, CP) and 2000 nm (signal pulse, SP). Building on prior works in the C-band, we address CP-SP temporal synchronization, fabrication challenges, and functional enhancements. The DCF composes lead-silicate PBG-08 glass for the cores and borosilicate UV-710 glass for the cladding, for the purpose of high refractive index contrast, strong nonlinear interaction, and extended transmission beyond the near infrared. Core diameter (2.4 μm) and spacing (3.9 μm) were tuned for improved dispersion, coupling, and synchronization within a compact 1 cm length. We developed a novel fabrication approach to maintain circular core shapes and minimize asymmetry, improving consistency and applicability of previous DCF designs. We analyzed effects of ±0.2 μm core ellipticity, finding minimal impact on group velocity and coupling length. The key importance characteristics of the optimized design promises higher switching contrast, reduced signal pulse distortions and extended wavelength range toward the mid-infrared. These predictions enhance the application potential of the analyzed specialty DCF in telecommunications, imaging, and sensing applications.