Highly efficient thermo-optic phase shifters for UV photonic applications

Area of Science:

• Photonics
• Materials Science
• Integrated Optics

Background:

• Thermo-optic phase shifters are crucial components in photonic integrated circuits.
• Aluminum oxide (Al2O3) offers promising material properties for UV photonic applications.
• Existing phase shifters often face limitations in efficiency or operating wavelength.

Purpose of the Study:

• To propose and demonstrate highly efficient thermo-optic phase shifters operating at UV wavelengths.
• To characterize device performance, including efficiency and bandwidth.
• To assess the feasibility of integrating these devices into a CMOS pilot line.

Main Methods:

• Fabrication of aluminum oxide photonic waveguides on a 200 mm CMOS pilot line.
• Integration of heaters and silicon undercut using metal lift-off and dry etching.
• Characterization using Mach-Zehnder interferometers to measure phase shift efficiency and response times.
• Analysis of the trade-off between phase shifter efficiency and response time.

Main Results:

• Demonstration of a phase shifter with an efficiency of 0.85 mW for a π phase shift at 360 nm wavelength.
• Measurement of 10-90% rise and fall times for bandwidth characterization.
• Achieved low insertion loss and high efficiency for the active modulator.

Conclusions:

• The developed thermo-optic phase shifters are highly efficient and operate effectively at UV wavelengths.
• The devices are compatible with existing 200 mm aluminum oxide UV photonics platforms.
• This work presents a promising active modulator for integrated UV photonic systems.