Plasmonic devices – tiny plasmonic hybrid receivers

Plasmonic hybrids are introduced to replace photonic optical hybrids for coherent reception. These plasmonic circuits offer a compact footprint and a fabrication compatible with many electronic platforms as one only relies on metallic layer stacks. To mitigate the plasmonic losses, we propose new designs with shortest propagation paths. Simulations predict plasmonic hybrids with compact footprints of less than 1 µm² and excess losses below 1 dB. In the experiment we fabricated plasmonic hybrids with 1 µm², excess losses of 3.3 dB, and excellent broadband performance for signals over more than 100 nm. These results need to be compared against reference optical hybrids with typical excess losses of 0.5 dB in the C-band. Our demonstrations show a path towards a fabrication platform with increasingly complex and compact plasmonic devices that can be cointegrated with electronics.