Integrated Bragg grating filters based on silicon-Sb₂Se₃ with non-volatile bandgap engineering capability

Area of Science:

• Photonics
• Materials Science
• Integrated Optics

Background:

• Integrated optical filters are crucial for reconfigurable photonic applications like wavelength division multiplexing (WDM) and quantum photonic networks.
• Existing reconfigurable filters often have large footprints or high static power consumption, limiting system development.
• There is a need for compact, low-loss, and energy-efficient reconfigurable optical filters.

Purpose of the Study:

• To design and experimentally demonstrate a novel reconfigurable hybrid Bragg grating filter.
• To integrate non-volatile phase change material (PCM) Sb2Se3 on silicon for enhanced filter performance.
• To overcome the limitations of existing filters in terms of footprint and power consumption.

Main Methods:

• Utilized a precise, modified coupling mode theory for filter design.
• Experimentally fabricated the filter by integrating Sb2Se3 PCM on a silicon platform.
• Characterized the filter's performance, including footprint, insertion loss, and switching capabilities.

Main Results:

• Achieved a compact filter footprint of 0.5 µm × 43.5 µm.
• Maintained a low insertion loss of <0.5 dB after multiple crystallization engineering steps.
• Demonstrated switching between low-loss transmission and Bragg reflection states with a high extinction ratio (>30 dB at 1504.85 nm).
• The filter breaks the typical tradeoff between insertion loss and tuning range.

Conclusions:

• The developed hybrid Bragg grating filter is a compact, low-loss, and non-volatile solution for reconfigurable photonic integrated systems.
• It offers a favorable alternative for large-scale reconfigurable photonic circuits, addressing current technological bottlenecks.
• Shows potential as a fundamental building block for future non-volatile reconfigurable photonic systems.