High-bandwidth Si/In2O3 hybrid plasmonic waveguide modulator

Abstract

A novel Si/In2O3 hybrid plasmonic waveguide modulator was experimentally realized by using an asymmetric directional coupler (ADC), which consists of a silicon photonic waveguide and a Si/In2O3 hybrid plasmonic waveguide. All the silicon cores are covered with a silica layer, above which there is a metal-oxide-semiconductor (MOS) capacitor consisting of the In2O3/HfO2/Au layers. The Au layer sitting on the top of the MOS capacitor works as the top-electrode while the In2O3 thin film covers the sidewall and contacts with the Au bottom-electrode. When the bias voltage is not applied, light launched from the silicon photonic waveguide is weakly coupled into the Si/In2O3 hybrid plasmonic waveguide, and thus one has a high transmission at the through port of the ADC. On the other hand, when the bias voltage is applied, the carrier density in the In2O3 layer is changed, which introduces some modification to the refractive index of the In2O3 thin film. As a result, light is strongly cross-coupled from the silicon photonic waveguide to a Si/In2O3 hybrid plasmonic waveguide, and one has low transmission at the through port. In this paper, an ultra-compact Si/In2O3 hybrid plasmonic waveguide modulator is realized with a 3.5-μm-long ADC. In the experiments, the fabricated waveguide modulator works well and exhibits a high modulation bandwidth of >40 GHz for the first time.

Sub-volt high-speed silicon MOSCAP microring modulator driven by high-mobility conductive oxide

“…In addition, we would like to point out that TCOs have emerged as a new E-O modulation material for integrated photonics in recent years 41 . Although high bandwidth was claimed 42 , 43 , these devices only demonstrated small-signal RF modulation and no clear eye diagrams have been reported above 5 Gb/s.…”

All-optical switching in epsilon-near-zero asymmetric directional coupler

“…In the recent two decades, transparent conductive oxide (TCO) such as indium tin oxide (ITO) 11 , aluminum-doped zinc oxide (AZO) 12 , cadmium oxide (CdO) 13 have attracted considerable interest in epsilon-near-zero (ENZ) spectral region. Such media exhibit a vanishing permittivity at ENZ wavelength, giving rise to a series of new physical phenomena 14 , such as enhanced electric field 15 , large optical nonlinearity 11 , ultrashort pulse interaction 16 , etc., and advanced applications including electro-optical modulator 17 , 18 , all-optical switch 19 , perfect absorber 13 , etc. For all-optical switching, ENZ TCO materials also have several advantages, such as greater refractive index change by pump excitation, ultrafast response time 11 , and intraband optical excitation 13 .…”

Quantum steerability of two qubits mediated by one-dimensional plasmonic waveguides

“…[31] With the development of nanotechnologies, strong and efficient coupling in plasmonic quantum electrodynamics is attainable and plasmons become a possible candidate for quantum information science. [32][33][34][35] In this paper, we investigate the dynamics of quantum steering between two separated qubits which are modulated by a one-dimensional plasmonic waveguide. Staring from the master equation that governs the dissipative dynamics of the two qubits for arbitrary initial states, we numerically calculate the quantum steerability using the semidefinite program.…”