High-efficiency Ge thermo-optic phase shifter on Ge-on-insulator platform

Area of Science:

• Photonics
• Materials Science
• Integrated Optics

Background:

• Silicon (Si) thermo-optic (TO) phase shifters are crucial for integrated photonics.
• Mid-infrared (MIR) applications require efficient and low-power photonic devices.

Purpose of the Study:

• To develop and characterize a novel Germanium (Ge) thermo-optic (TO) phase shifter on a Ge-on-insulator (GeOI) platform.
• To evaluate the performance of Ge-based TO phase shifters for MIR integrated photonics.

Main Methods:

• Fabrication of a Ge TO phase shifter on a GeOI wafer.
• Numerical analysis of Ge and Si TO phase shifter performance.
• Experimental characterization of phase shift and operating power at 1.95 μm wavelength.

Main Results:

• The Ge TO phase shifter demonstrated three times higher modulation efficiency compared to Si TO phase shifters.
• Achieved a phase shift of π with an operating power of 7.8 mW.
• This operating power is less than half of previously reported Si TO phase shifters.

Conclusions:

• Ge TO phase shifters on GeOI platforms are highly promising for high-performance, low-power MIR photonic integrated circuits.
• These devices are suitable for diverse applications in sensing and communication.
• The superior properties of Ge enable advancements in MIR integrated photonics.