Monolithic temperature-insensitive high-Q Ta₂O₅ microdisk resonator

Area of Science:

• Photonics and optical engineering
• Materials science for optical devices
• Integrated optics

Background:

• High-Q microdisk resonators are crucial for integrated photonic circuits.
• Tantalum oxide (Ta₂O₅) offers potential for optical applications due to its material properties.
• Achieving temperature stability in resonators is a significant challenge for practical applications.

Purpose of the Study:

• To demonstrate a high-Q tantalum oxide (Ta₂O₅) microdisk resonator.
• To investigate the temperature insensitivity and optical stability of these resonators.
• To evaluate the potential of Ta₂O₅ microdisk resonators for integrated photonic devices.

Main Methods:

• Fabrication of Ta₂O₅ microdisk resonators using electron-beam lithography and inductively coupled plasma reactive-ion etching.
• Characterization of optical properties, including Q-factor and resonant wavelength.
• Thermal annealing at 600°C to improve resonator performance.
• Testing of temperature-dependent resonant wavelength shift and optical stability under elevated input power.

Main Results:

• Achieved a loaded Q-factor of 4.25 × 10⁵ at 1,550 nm, increasing to ~9.3 × 10⁵ after annealing.
• Demonstrated remarkable temperature insensitivity with a suppressed resonant wavelength shift (<10 pm/°C) over a 100 nm bandwidth.
• Maintained high optical stability, with no degradation in Q-factor or extinction ratio under elevated input power.

Conclusions:

• The fabricated Ta₂O₅ microdisk resonators exhibit high Q-factors and exceptional thermal stability.
• These resonators are a promising platform for advanced integrated photonic applications.
• Potential applications include on-chip narrow-linewidth lasers and high-precision sensing devices.