Hybrid Plasmonic Waveguide based 3×3 Multimode Interferometer for Compact 120° Optical Hybrid

Based on hybrid plasmonic waveguide (HPW), we propose a compact 3×3 multimode interferometer (MMI) for 120° optical hybrid. Also, tapered HPW sections are implemented to improve the coupling efficiencies for lights coupled into/out of the multimode section. The simulation results show that at a wavelength of 1550 nm, the transmission rate of the 3×3 HPW-MMI is 0.692 (1.61 dB loss), the maximum transmission imbalance is 0.43 dB, and the phase error is 4.66°.