Magic Silicon Dioxide for Widely Tunable Photonic Integrated Circuits

Area of Science:

• Photonics and Optical Engineering
• Materials Science
• Integrated Optics

Background:

• Integrated photonic circuits are crucial for data communication, sensing, and optical computing.
• Tunable and reconfigurable photonic components commonly use the thermo-optic effect.
• Standard materials have limited tuning windows and lack bidirectional thermal tuning capabilities.

Purpose of the Study:

• To develop a method for deterministic thermo-optic tuning of photonic devices.
• To achieve bidirectional thermal tuning on a single chip.
• To improve the tunability and reduce thermal crosstalk in integrated photonic devices.

Main Methods:

• Optimized deposition conditions of silicon dioxide using inductively coupled plasma chemical vapor deposition (ICPCVD).
• Demonstrated deterministic integration of positive and negative wavelength shifts on amorphous silicon carbide (a-SiC), silicon nitride (SiN), and silicon-on-insulator (SOI) platforms.
• Fabricated a tunable coupled ring optical waveguide (CROW) using a single heater and employed low-temperature deposition with lift-off for device isolation.

Main Results:

• Achieved deterministic thermo-optic tuning of silicon dioxide without significant optical losses.
• Demonstrated bidirectional wavelength shifts on a single chip across multiple photonic platforms.
• Observed up to a 10-fold improvement in thermo-optic tunability and athermal ring resonators with shifts as low as 1.5 pm/°C.
• Reduced thermal crosstalk by at least 2 orders of magnitude through device isolation.

Conclusions:

• The developed ICPCVD method for silicon dioxide enables precise control over thermo-optic properties.
• This technique allows for bidirectional thermal tuning on a single photonic chip, a significant advancement.
• The findings pave the way for novel photonic architectures with enhanced tunability and reduced thermal crosstalk.