Energy-efficient thermo-optic silicon phase shifter with well-balanced overall performance

Area of Science:

• Photonics and Optical Engineering
• Materials Science and Engineering

Background:

• Silicon photonic integrated circuits (PICs) are vital for numerous applications, requiring efficient phase tuning.
• Existing optical phase shifter designs often compromise on key performance metrics like power consumption, insertion loss, footprint, or modulation bandwidth.
• Achieving a balanced performance across these parameters is critical for advancing large-scale integrated photonics.

Purpose of the Study:

• To experimentally demonstrate a novel thermo-optic phase shifter with balanced performance characteristics.
• To address the limitations of current phase shifter technologies in silicon photonics.
• To provide a viable solution for efficient phase tuning in complex photonic integrated circuits.

Main Methods:

• Fabrication of a thermo-optic phase shifter utilizing a densely distributed silicon spiral waveguide on a silicon-on-insulator (SOI) platform.
• Experimental characterization of the phase shifter's electrical power consumption, optical insertion loss, physical footprint, and modulation bandwidth.
• Implementation using a standard silicon photonics fabrication process without specialized features like silicon air trenches or undercut processes.

Main Results:

• The demonstrated thermo-optic phase shifter achieves a low electrical power consumption of 3 mW for a π phase shift.
• Optical insertion loss is measured at 0.9 dB per phase shifter.
• The device exhibits a compact footprint of 67×28µm², achievable with standard fabrication.
• A modulation bandwidth of 39 kHz was experimentally determined.

Conclusions:

• The developed silicon spiral waveguide thermo-optic phase shifter offers a well-balanced performance profile across critical parameters.
• This design represents a significant advancement for large-scale silicon photonic integrated circuits by overcoming previous trade-offs.
• The achieved performance metrics make it suitable for practical implementation in various photonic applications.