Ultracompact Silicon-Conductive Oxide Nanocavity Modulator with 0.02 Lambda-Cubic Active Volume.

Area of Science:

• Photonics
• Materials Science
• Electrical Engineering

Background:

• Silicon photonic modulators face limitations in size and energy efficiency due to the plasma dispersion effect.
• Diffraction limits further constrain the performance of conventional silicon photonic modulators.

Purpose of the Study:

• To develop an ultracompact and energy-efficient electro-optic modulator.
• To overcome the limitations of existing silicon photonic modulator technologies for on-chip optical interconnects.

Main Methods:

• Integration of voltage-switched transparent conductive oxide with a one-dimensional silicon photonic crystal nanocavity.
• Exploitation of dual-mode operation combining cavity resonance and optical absorption.
• Utilizing refractive index modulation from both conductive oxide and silicon waveguide.

Main Results:

• Achieved an ultracompact device footprint of 0.6 × 8 μm² with a modulation volume of 0.06 μm³.
• Demonstrated low optical loss (0.5 dB), a moderate Q-factor (>1000), and high energy efficiency (46 fJ/bit).
• Developed a metal-free, hybrid silicon-conductive oxide nanocavity modulator.

Conclusions:

• The novel modulator design offers a significant advancement over traditional silicon photonic modulators.
• This technology paves the way for next-generation electro-optic modulators essential for future on-chip optical interconnects.