Fast and efficient silicon thermo-optic switching based on reverse breakdown of pn junction

Area of Science:

• Photonics and Optoelectronics
• Materials Science
• Semiconductor Devices

Background:

• Thermo-optic switches are crucial for optical communication networks.
• Existing silicon thermo-optic switches face limitations in speed and efficiency.
• Reverse breakdown in pn junctions offers a novel heating mechanism.

Purpose of the Study:

• To propose and demonstrate a novel silicon thermo-optic switch.
• To leverage reverse breakdown for enhanced performance.
• To assess the switch's speed, efficiency, and figure of merit for optical interconnects.

Main Methods:

• Embedding a pn junction into the center of a silicon waveguide.
• Utilizing the reverse breakdown phenomenon for direct waveguide heating.
• Characterizing switching times and thermal tuning efficiency of a microring resonator.

Main Results:

• Achieved fast switching on/off times of 330 ns and 450 ns.
• Demonstrated efficient thermal tuning of 0.12 nm/mW for a 20 μm radius microring resonator.
• Obtained a high figure of merit of 8.8 mW·μs.

Conclusions:

• The proposed silicon thermo-optic switch offers significant improvements in speed and efficiency.
• Direct heating via reverse breakdown is an effective strategy for high-performance thermo-optic devices.
• This technology holds substantial potential for future optical interconnect applications.