Low-loss GaO_x-core/SiO₂-cladding planar waveguides on Si substrate.

Area of Science:

• Materials Science
• Optoelectronics
• Nanotechnology

Background:

• Gallium oxide (GaOx) possesses unique properties making it suitable for high-power electronic and optical devices.
• Integrated photonics requires materials with excellent optical transmission and high damage thresholds.

Purpose of the Study:

• To demonstrate low-loss gallium oxide (GaOx)-core/silica (SiO2)-cladding waveguides on a silicon substrate.
• To characterize the optical transmission and loss mechanisms in these waveguides.
• To evaluate the potential of GaOx for high-power integrated photonic applications.

Main Methods:

• Fabrication of GaOx-core/SiO2-cladding waveguides on Si substrate.
• Optical characterization at 633 nm, 1064 nm, and 1550 nm wavelengths.
• Post-fabrication annealing treatments and their effect on optical properties.
• Pump-probe experiments and nonlinear measurements using a 250 fs laser.
• Laser-induced damage threshold (LIDT) measurements.

Main Results:

• Achieved propagation losses of -0.4±0.1 dB/cm (633 nm), -0.3±0.2 dB/cm (1064 nm), and -2.4±0.5 dB/cm (1550 nm).
• Identified major waveguide loss mechanisms through linear and nonlinear optical measurements.
• Demonstrated a high LIDT of >2.5 J/cm² at 250 fs pulse width.

Conclusions:

• GaOx-based waveguides on Si exhibit promising low-loss characteristics for optical applications.
• The material's high LIDT supports its potential for high-power integrated photonic devices.
• Further optimization of fabrication and annealing processes can enhance performance.