Nonlinear Dynamics of Higher-Order Quasi-Phase-Matched Dispersive Waves Formation in Dispersion-Oscillating Liquid-Core Fibers

Here, the concept of generating higher-order dispersive waves (DWs) via quasi-phase-matching (QPM) in periodically dispersion-modulated liquid-core fibers are demonstrated by generating distinct narrowband sidebands generated outside the conventional supercontinuum (SC) spectrum. Through controlled partial core collapse, the commonly used phase-matching (PM) condition is amended by an additional grating-related term. This results in the generation of ultrashort higher-order DWs controlled by the grating parameters, extending the conventional SC spectrum up to 3 mu m$\umu {\rm m}$. Of particular interest is the excellent overlap of the QPM-peaks obtained from experiments, simulations, and PM considerations, showing the quality of the implementation approach and allowing for controlled narrowband peaks generation even for femtosecond input pulses. In summary, this multicolor generation concept embodies a versatile photonic platform with unique dispersion control capabilities for the transfer of spectral power into selected narrowband spectral intervals. It stands out with its unique capabilities, making it well-suited for applications in diverse fields like bioanalytics, life sciences, quantum technology, and metrology. Quasi-phase-matched dispersive wave formation represents a novel nonlinear frequency conversion scheme to transfer electromagnetic energy into tailored narrowband spectral domains. Using ultrashort pulses, this work demonstrates the capabilities of core-diameter modulated liquid core fibers to generate strong sidebands outside conventional supercontinua of silica fibers that can be tuned by the properties of the modulation. image