Plasmonic phase modulator consisting of a metal-insulator-metal waveguide and an electro-optic material.
Plasmonics refers to the manipulation of signals at optical frequencies along metal-dielectric interfaces at the nanometer scale. Key to this technology is the coupling between light and the electrons at the metal surface, called surface plasmon polaritons (SPP). In such structures, these SPPs are strongly confined in a metal-insulator-metal (MIM) waveguide, where they interact with the electro-optic material in the slot. When a voltage is applied across the electrodes, the optical property of the electro-optic material changes the phase of the SPPs, having an effect on the path length of the optical wave. This configuration permits the construction of highly effective phase shift modulators (PSM).
The mentioned tight confinement works at the micrometer scale providing a breakthrough in terms of footprint, orders of magnitude smaller than other technologies. A phase shifter can be implemented as small as 10 µm in length, having a positive effect on the photonic losses.
Plasmonic devices use the metal of the MIM waveguide as their own electrical contact, which allows for small capacitances that ultimatively boost the switching speed thanks to small RC time constants. Further, in contrast to traditional structures, plasmonic devices do not experience a spatial walk-off of the optical wave.
Finally, the consequence of small structures in electronics is the reduced power dissipation, of at least one order of magnitude. Since plasmonic structures can be implemented as lumped high-impedance devices, transmission-line effects can be ignored, and further power dissipation reduction is possible when driven with a high-impedance, high-speed driver circuit. As a consequence, plasmonics is a key to next-generation signal transmission in the THz regime.
Small Dimensions
Plasmonics offers dense integration with sizes of a few 10s µm. This overcomes the size mismatch between small-scale electronics and large-scale photonics.
Features
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On-chip device sizes of a few 10s of µm
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Package sizes of 20 mm x 10 mm
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Minimize RF losses and attach directly to RF source
Large Bandwidth
Thanks to small RC time constants plasmonic devices offer a unique electro-optic bandwidth well into the THz regime.
Features
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Demonstrated on-chip bandwidth of up to 500 GHz
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Capable of operation in O-E-S-C-L-U optical bands
Low Power Usage
The power consumption in fiber-optic communication networks strongly depends on the system design that requires new and highly efficient components. The high bandwidth of plasmonic devices minimizes the need of power-hungry DSP and FEC needs on a system level.
