Fig. 1
a, b The schematic configuration and geometric parameters of a U-shaped nanocavity-coupled waveguide system and the corresponding spectral transmittance respectively. The inset in b shows the electric field (E y) distribution at a wavelength of 2437 nm. The parameters are set as W = 800 nm, L = 620 nm, d = 20 nm, W U = 150 nm, L U = 120 nm, L 1 = 220 nm, τ = 1 ps, μ c1 = 0.3 eV, and μ c2 = 0.9 eV. The perfectly matched layers (PML) with a width of 50 nm are implemented on the top and bottom of the computation domain to eliminate undesired reflections from the domain boundary