Ultrafast Dual-Wavelength 1 μm -2 μm All-Optical Switching Based on All-Solid Dual-Core Fiber

This study focuses on optimizing a dual-core fiber (DCF) structure for femtosecond nonlinear dual-wavelength switching applications, previously demonstrated in the C-band. This contribution aims to synchronize control and signal pulses (CP, SP) at 1030 nm and 2000 nm, respectively, thereby proposing improvements to the DCF fabrication process. Our technological approach relies on the utilization of lead-silicate PBG-08 glass as the core and borosilicate UV-710 glass as the cladding material, ensuring a high index contrast, highly nonlinear cross interaction, and advantageous spectral profiles of the DCF. Through the optimization of core parameters such as shape, diameter, and core-to-core distance, we achieved enhancements in CP-SP synchronization, dispersion engineering, and coupling characteristics, while maintaining device compactness with a mere 1 cm length. The optimized DCF features cores with a diameter of $2.4 \mu \mathrm{m}$ and a core-to-core distance of $3.9 \mu \mathrm{m}$. Additionally, we introduced a novel fabrication approach to maintain circular core shapes and mitigate the asymmetry inherent in previously fabricated DCFs. This innovative method represents a significant advancement in DCF fabrication, offering promising prospects for dual-wavelength all-optical switching. The presented numerical results predict a reduction in switching energy and an improvement in switching contrast, with a simultaneous shift of the switching wavelength towards the mid-infrared spectral region.