(color online) (a) Output transmittance spectra of the power splitter of Fig. 7. Distributions of the H_z fields in the xy cross section of the power splitter for resonance wavelengths of (b) λ = 6.1 μm and (c) λ = 10.2 μm. d and L′ are assumed to be 12 nm and 268 nm, respectively. Other simulation parameters are the same as those in Fig. 2.