A high-speed silicon optical modulator based on a metal-oxide-semiconductor capacitor

Area of Science:

• Photonics and optoelectronics
• Materials science
• Electrical engineering

Background:

• Silicon is a dominant material in electronics but faces challenges in photonics due to slow optical modulators.
• Existing silicon-waveguide modulators are limited to ~20 MHz, hindering integration with high-speed electronics.
• III-V semiconductors and lithium niobate offer faster modulation but lack silicon's integration capabilities.

Purpose of the Study:

• To develop a high-speed optical modulator using silicon.
• To overcome the speed limitations of current silicon photonic devices.
• To enable monolithic integration of optical modulators with CMOS electronics.

Main Methods:

• An all-silicon optical modulator was designed using a metal-oxide-semiconductor (MOS) capacitor structure.
• The MOS capacitor was embedded within a silicon waveguide to facilitate optical phase modulation.
• Device performance was experimentally evaluated for modulation bandwidth.

Main Results:

• Demonstrated an all-silicon optical modulator with a modulation bandwidth exceeding 1 GHz.
• Achieved significantly higher speeds compared to previous silicon-waveguide modulators (~20 MHz).
• The demonstrated modulator is compatible with complementary metal-oxide-semiconductor (CMOS) processing.

Conclusions:

• The developed MOS capacitor-based silicon modulator offers a viable solution for high-speed photonic applications.
• This technology paves the way for integrating advanced optical functionalities directly onto silicon chips.
• Enables the creation of high-performance, cost-effective silicon photonic devices with advanced electronic integration.