Enhanced supercontinuum spectral broadening in thin film lithium niobate tapered waveguides

On-chip supercontinuum (SC) generation holds great potential for a wide range of applications, including imaging, optical coherence tomography, spectroscopy, and optical frequency comb technologies [1]. However, achieving broad and coherent SC on-chip is often constrained by the limitations of the material. Recent advances in the nanoscale fabrication of thin-film lithium niobate (TFLN) waveguides have shown great progress for the development of nonlinear devices, offering a wide transparency window, low propagation losses, and both χ(2) and χ(3) nonlinearities [2], which enables f − 2 f interferometry and cascaded nonlinear processes. As such, effective SC generation in TFLN have already shown promising performance [3], and chirped periodically poled waveguides have shown to expand the bandwidth significantly in the visible [4].