Sub-Femtojoule Hybrid Plasmonic Optical Modulator

Abstract

A highly compact optical modulator is proposed and analyzed. The modulator is based on the hybrid plasmonic waveguide platform. The structure of the modulator is built from silicon, silver, and electro-optical polymer layers. Hybrid plasmonic modes of symmetric and asymmetric natures excited in the structure were investigated. The symmetric mode is characterized by its lower propagation loss, so it was selected for the excitation of the device. The modulator's operation mechanism is based on the racetrack resonator configuration. Full three-dimensional electromagnetic analysis was performed around the 1.55-μm telecommunication wavelength. Different parameters such as the power coupling to the bus waveguide, the bend loss, the propagation loss, and the Q-factor of the resonances were studied in order to optimize the racetrack resonator design. The modulator is characterized by its extremely low energy consumption of 0.5 fJ/bit, high modulation depth of 10.5 dB, while the insertion losses were limited to 0.5 dB.

Sub-femtojoule optical modulation based on hybrid plasmonic devices

“…1, where on top of the Si substrate, the layers are arranged from bottom to top as; SiO 2 (BOX)-Si-EOP-Ag-EOP-Si. The optimization of the waveguide in order to minimize insertion losses was demonstrated in Sherif et al (2019). Hereby, we use the same optimized waveguide parameters such that waveguide width is 400 nm, layers thicknesses are:t Si(bottom) = 140nm , t EOP(bottom) = t Ag = t EOP(top) = 20nm, and t Si(top) = 160nm.…”

“…Thus, one DLD-164 layer has a capacitance of 9 fF, while the two parallel layers have a total capacitance of 18 fF. The resistivity of the 10 17 cm −3 n-doped Si is equal to 0.087 Ωcm (Sherif et al 2019). So, using:…”

“…However, it is also possible to integrate plasmonic materials with strong EO materials to build the Plasmonic organic hybrid (POH) platform (Robinson et al 2018;Koos et al 2015). POH modulators based on directional couplers (Zografopoulos et al 2016a;Thomaschewski et al 2020), ring resonators (Zografopoulos et al 1039;Sherif et al 2019), and MZIs (Haffner et al 2015) have shown promising performances.…”

“…In this work, we demonstrate sub-femtojoule optical modulation based on the hybrid plasmonic platform where we utilize the waveguide design from our previous work on a low loss waveguide structure which is composed of Si-Ag-EOP layers, where an optical modulator based on a racetrack resonator was demonstrated (Sherif et al 2019). We hereby implement a more recently used EOP; the DLD-164 chromophore which is a high linear χ (2) material (Haffner et al 2015;Elder et al 2014) in our waveguide structure.…”

Plasmonics for Telecommunications Applications

“…The system can work in the linear and nonlinear regimes, through proper modulating of the pump and probe beams, reaching modulation bandwidths around 1.5 THz. Another recent proposal considers a hybrid plasmonic modulator, combining silicon and electro-optic polymers (EOP) with silver, built by a straight waveguide coupled to a ring resonator [146]. The system is developed, from bottom to top, as silicon-EOP-silver-EOP-silicon on SiO 2 substrate, as depicted in Figure 3f.…”