All-Plasmonic IQ Modulator With a 36 μm Fiber-to-Fiber Pitch

A most compact all-metallic high-speed in-phase and quadrature modulator with a 36 μm fiber-to-fiber pitch operating at 200 Gbit/s is introduced. All components of the modulator are made of metal: The vertical crating couplers, the waveguides, polarization rotators, splitters, and phase shifters. As the modulator relies on substrate-independent processes, it can basically be put down on any smooth layer. The modulator is interconnected to a multicore fiber for optical input and output coupling. We demonstrate 100 GBd signal modulation with a quadrature phase-shift keying modulation format and a bit-error ratio below the hard-decision forward error correction. The metallic modulator shows the potential of plasmonics in offering highest speed and advanced modulations on a smallest possible footprint. The simple fabrication makes it attractive for low-cost applications such as short-haul and data-center networks.