Ultra-compact Si/In$_2$O$_3$ hybrid plasmonic waveguide modulator with a high bandwidth beyond 40 GHz

TL;DR

This paper presents a novel ultra-compact Si/In$_2$O$_3$ hybrid plasmonic waveguide modulator with a record-high bandwidth exceeding 40 GHz, achieved through an innovative asymmetric directional coupler design.

Contribution

The work introduces the first silicon-doping-free metal-oxide-In$_2$O$_3$ capacitor integrated in a compact waveguide modulator with ultra-high bandwidth.

Findings

Achieved modulation bandwidth >40 GHz.

Realized a 3.5-$ ext{μ}$m-long asymmetric directional coupler.

Demonstrated a novel Si/In$_2$O$_3$ hybrid plasmonic waveguide modulator.

Abstract

Optical modulators are required to have high modulation bandwidths and a compact footprint. In this paper we experimentally demonstrate a novel Si/In$_2$O$_3$ hybrid plasmonic waveguide modulator, which is realized by an asymmetric directional coupler (ADC) consisting of a silicon photonic waveguide and a Si/In$_2$O$_3$ hybrid plasmonic waveguide. The optical signal is modulated by radio-frequency (RF) signal applied on the Au electrodes at the top of MOS capacitor and contacting the In$_2$O$_3$ thin film. The record-high modulation bandwidth of >40 GHz is realized by a silicon-doping-free metal-oxide-In$_2$O$_3$ capacitor integrated in a 3.5-$\mu$m-long asymmetric directional coupler (ADC) for the first time.