Diode-assisted microheaters for programmable photonic integrated circuits.

Area of Science:

• Photonics
• Integrated Optics
• Microelectronic Engineering

Background:

• Programmable photonic integrated circuits (PPICs) rely on Mach-Zehnder interferometer (MZI) switches for robust designs.
• Traditional MZI designs use microheaters on both arms to manage phase errors, but this increases complexity and power consumption.
• Existing methods often activate only one microheater, leading to suboptimal power efficiency and scalability challenges due to increased control channels and bond pads.

Purpose of the Study:

• To propose and validate a novel diode-assisted microheater (DAM) architecture for silicon photonics.
• To enable selective driving of MZI microheaters without increasing electronic control complexity or pad count.
• To demonstrate a scalable, power-efficient, and foundry-compatible solution for PPICs.

Main Methods:

• Implementation of the DAM architecture on a standard silicon photonics technology platform.
• Comprehensive electrothermal simulations and CMOS foundry fabrication.
• DC and AC characterization, including resistance modeling and performance validation in a 1x4 power splitter.

Main Results:

• The DAM architecture is confirmed to be CMOS foundry fabrication feasible.
• Efficient thermal tuning was achieved with low power dissipation (~50 mW) and fast response times (~20 μs).
• Precise phase correction in a 1x4 power splitter resulted in uniform power splitting (±0.015 dB) across a 40 nm bandwidth.
• A power consumption reduction exceeding 50% was experimentally demonstrated compared to conventional single-microheater designs.

Conclusions:

• The diode-assisted microheater (DAM) architecture provides a scalable and power-efficient solution for PPICs.
• The DAM is fully compatible with standard silicon photonics foundry processes.
• This innovation addresses key challenges in PPIC design, paving the way for next-generation integrated photonic devices.