Reconfigurable Optical Logic Gates and 2-Bit Decoder Using Multiport Directional Couplers

Abstract: We demonstrate a reconfigurable photonic platform capable of implementing both optical logic gates and a 2-bit decoder on the same device. The architecture is based on cascaded multiport directional couplers interleaved with thermo-optic phase shifters, enabling programmable $N \times N$ unitary transformations. Optimal heater voltages for phase control are determined through Bayesian optimization. The devices operate reliably across multiple wavelengths with 50 GHz spacing, suggesting potential for wavelength-parallel optical processing. These results highlight a pathway toward compact, programmable and integrated photonic circuits.