Plasmonic platform for seven logic gates and higher-level combinational and coding/decision functions at 1,310 nm

Abstract Ultracompact all-optical logic is essential for reducing optical–electrical–optical conversions in future on-chip processing. This work develops a single reusable plasmonic segment that realizes the complete set of seven Boolean logic gates and higher-level combinational and coding/decision functions (half adder, full adder, half subtractor, 1 bit comparator, 4 × 2 encoder, and 2 × 4 decoder) at 1,310 nm in the O-band. The device employs a silver/zinc-oxide/silver (Ag/ZnO/Ag) metal–insulator–metal (MIM) waveguide coupled to a hollow hexagonal ring resonator, where the output level is controlled by interference among signals injected from the excited ports after coupling through the ring resonator. The structure is evaluated in COMSOL Multiphysics using a 2-D frequency-domain finite-element model. The seven-gate library achieves a contrast ratio of 4.42–13.59 dB with modulation depth above 91 %, while the implemented combinational and coding/decision circuits maintain modulation depth (up to 99.32 %) and clear ON/OFF discrimination (e.g., 10.56 dB for the encoder and up to 12.06 dB for the decoder). Spectral robustness is quantified using a fine 1 nm wavelength sweep, yielding a full width at half maximum (FWHM) of ≈29.72 nm for all functions, corresponding to a quality factor of Q ≈ 44, avoiding ambiguity associated with coarse spectral sampling.