Monolithic optical link in silicon-on-insulator CMOS technology

Area of Science:

• Photonics
• Integrated Optics
• Semiconductor Devices

Background:

• Silicon photonics is crucial for integrated optical links.
• Wide-spectrum optical communication requires efficient light sources and detectors.
• Thermal management is a key challenge in integrated optoelectronic devices.

Purpose of the Study:

• To present a monolithic, wide-spectrum optical link in silicon-on-insulator CMOS technology.
• To analyze optical coupling in both avalanche-mode and forward-mode silicon light-emitting diodes (LEDs).
• To investigate the impact of thermal coupling and evaluate heat sink effectiveness.

Main Methods:

• Fabrication of a silicon (Si) LED and Si photodiode (PD) using vertical abrupt n+p junctions.
• Optical coupling analysis under various designs and bias conditions for LED operation modes.
• DC and pulsed transient measurements to assess thermal coupling and heat sink performance.

Main Results:

• Demonstrated a monolithic, laterally-coupled optical link with a wide spectrum (350 nm to 1270 nm).
• Identified slow thermal coupling (ms time constants) from avalanche-mode LED to PD due to heating.
• Showcased a ∼ 6x reduction in PD junction temperature change with an integrated heat sink.

Conclusions:

• The developed optical link is suitable for wide-spectrum applications in CMOS technology.
• Thermal management strategies, like integrated heat sinks, are vital for reliable optical link performance.
• This work enables integrated wide-spectrum optical links for smart power technologies.