Topological gap solitons in equidistant lithium niobate waveguide arrays

Abstract

Equidistant 1D arrays of thin film lithium niobate waveguides can exhibit non-trivial topology due to a specific interplay between inter- and intra-modal couplings of two families of guided modes. In this work we analyze two-colour spatial solitons, emerging due to ${\chi }_2$ nonlinear interactions between the modes of non-trivial topology in the fundamental harmonic field, and modes of trivial topology in the second harmonic field. We discuss solitons localized in the bulk of the array (bulk solitons), and at an edge of a finite-size array (edge solitons). The latter emerge due to the nonlinear interactions between a topological edge mode in the fundamental harmonic and bulk modes in the second harmonic. We reveal that for each type of soliton, bulk or edge, there generally exist two families of solutions with different internal structures and ranges of propagation constants. All bulk solitons can only be excited above a certain power threshold dictated by the coupling strength in the second harmonic field and the phase matching between the fundamental and second harmonics. The power threshold for edge solitons generally appears to be much lower, and, by tuning the phase matching, it can be reduced to zero.

arXiv commentPublished in the special Issue of Low Temperature Physics dedicated to the 80th anniversary of Prof. Alexander S. Kovalev

References in corpus (17)

• Integrated photonics on thin-film lithium niobate
• Nonlinear topological photonics
• Surface Impedance and Bulk Band Geometric Phases in One-Dimensional Systems
• Observation of novel edge states in photonic graphene
• A topological source of quantum light
• Band topology in classical waves: Wilson-loop approach to topological numbers and fragile topology
• Nonlinear one-way edge-mode interactions for frequency mixing in topological photonic crystals
• Topological edge states and gap solitons in the nonlinear Dirac model
• Chirality of topological gap solitons in bosonic dimer chains
• Weakly nonlinear topological gap solitons in Su-Schrieffer-Heeger photonic lattices
• Topological states in arrays of optical waveguides engineered via mode interference
• Topological and flat bands states induced by hybridized interactions in one-dimensional photonic lattices
• Topological Dissipative Photonics and Topological Insulator Lasers in Synthetic Time-Frequency Dimensions
• Topological edge states in equidistant arrays of Lithium Niobate nano-waveguides
• Temporal quadratic solitons and their interaction with dispersive waves in Lithium Niobate nano-waveguides
• A mono-atomic orbital-based 1D topological crystalline insulator
• Topological edge solitons in \{chi}(2) waveguide arrays