Power-efficient silicon nitride thermo-optic phase shifters for visible light

Area of Science:

• Integrated Photonics
• Materials Science
• Optoelectronics

Background:

• Silicon nitride photonics is crucial for visible light applications.
• Thermo-optic phase shifters require efficient designs to minimize power consumption.
• Integrated photonic platforms enable miniaturization and enhanced functionality.

Purpose of the Study:

• To demonstrate power-efficient thermo-optic silicon nitride waveguide phase shifters.
• To operate these phase shifters at blue, green, and yellow wavelengths.
• To integrate these devices into active photonic circuits.

Main Methods:

• Fabrication of silicon nitride waveguides on 200-mm silicon wafers using deep ultraviolet lithography.
• Implementation of a suspended structure and multi-pass waveguide design for reduced power consumption.
• Integration of phase shifters into Mach-Zehnder interferometer switches.

Main Results:

• Achieved low power consumption for a π phase shift: 0.78 mW (445 nm), 0.93 mW (488 nm), 1.09 mW (532 nm), and 1.20 mW (561 nm).
• Demonstrated fast switching speeds with 10-90% rise/fall times of approximately 570/590 μs.
• Successfully integrated phase shifters into a visible-light integrated photonics platform.

Conclusions:

• The developed silicon nitride waveguide phase shifters are highly power-efficient for visible light.
• These devices are suitable for active integrated photonic applications requiring low power and fast switching.
• The fabrication process is compatible with standard silicon wafer manufacturing.