Nonlinear switch and spatial lattice solitons of photonic s-p orbitals

We develop fs laser-fabricated asymmetric couplers and zig-zag arrays consisting of single- and two-mode waveguides with bipartite Kerr nonlinearity in borosilicate (BK7) glass substrates. The fundamental mode (s orbital) is near resonance with the neighboring higher-order p orbital, causing efficient light transfer at low power. Due to Kerr nonlinearity, the coupler works as an all-optical switch between s and p orbitals. Single- and double-peak spatial lattice solitons of s-p orbitals form due to the bipartite nature of the on-site nonlinearity. We probe highly localized bulk and edge solitons, peaked at the s and p orbitals, spectrally residing in the photonic bandgap. Our work will be important for exploring inter-orbital couplings and nonlinear interactions in intricate photonic devices.