Performance comparison of Zn-MOF and Nb2CTx/Co3O4 coatings on side-polished fibers for enhanced four-wave mixing at 1.5 µm

• Zn-MOF and Nb 2 CT x /Co 3 O 4 as novel material in four-wave mixing generation. • Generation of four wave mixing with conversion efficiency of −42.5 dB. • Significant enhancement in four wave mixing generation up to 646% • Both Zn-MOF and Nb 2 CT x /Co 3 O 4 increased the FWM tuning from 3.56 nm to 4.6 nm. This study investigates the enhancement of the four-wave mixing (FWM) process in side-polished optical fibers (SPFs) operating in the 1.5-µm telecommunication band through functionalization with a Zinc-based Metal-Organic Framework (Zn-MOF) and Cobalt Oxide nanocomposite (Nb 2 CT x /Co 3 O 4 ). The side-polishing technique creates a platform for intense evanescent-field interaction, significantly boosting local optical intensity and thereby strengthening the nonlinear response within a compact device footprint. The experimental setup employed two tunable continuous-wave laser sources as pump and signal inputs, which were combined and amplified by an erbium-doped fibre amplifier (EDFA) before being launched into a side-polished fibre (SPF). The deposition of Zn-MOF and Nb 2 CT x /Co 3 O 4 composites onto the polished fiber surface yielded a substantial improvement in the nonlinear performance, with measured conversion efficiency enhancements of up to 16.0% compared to an uncoated SPF. A stability assessment conducted over 60 min confirmed the robust and consistent generation of the FWM idler. These findings underscore the potential of advanced-material-functionalized SPFs as efficient, compact nonlinear platforms for all-optical signal processing in the conventional telecommunication band.