Formation of Energy-Efficient Multi-Octave Frequency Combs in Nanophotonic Parametric Oscillators

Multi-octave frequency combs which coherently unite disparate portions of the spectrum are important for myriad applications including spectroscopy [1] and single-cycle pulse synthesis [2]. Such broadband combs are typically generated through coherent supercontinuum generation processes based on nonlinear interactions [3] but often require fibers and other bulky components driven by high-energy pulsed lasers. Recently, integrated photonics has reduced the size and energy requirements of supercontinuum generation [4]. In particular, multi-octave spectra have been achieved with quadratic nonlinearity in nanophotonic lithium niobate [5] but have typically required pJ pulse energies and infrared pumping to achieve significant coverage at long wavelengths.