Low-loss GeO(2) optical waveguide fabrication using low deposition rate rf sputtering.

Area of Science:

• Materials Science
• Optoelectronics
• Photonics

Background:

• Optical waveguides are crucial for photonic integrated circuits.
• Achieving low propagation loss in thin-film waveguides is a key challenge.
• Germanium dioxide (GeO2) is a promising material for optical applications.

Purpose of the Study:

• To prepare low-loss GeO2 thin-film optical waveguides.
• To investigate the impact of fabrication conditions on waveguide properties.
• To determine the suitability of GeO2 waveguides for a wide wavelength range.

Main Methods:

• Radio frequency (RF) reactive sputtering using a GeO2 target in an argon-oxygen atmosphere.
• Optimization of deposition rate and annealing processes.
• Ellipsometry for refractive index measurement.
• Propagation loss measurements at various wavelengths.

Main Results:

• Low propagation losses (<0.7 dB/cm for TE0 mode at 0.63 microm) were achieved.
• Waveguide attenuation significantly decreased with low deposition rates and appropriate annealing.
• The refractive index of GeO2 films was measured to be 1.6059 at 5461 A.
• GeO2 waveguides demonstrated low losses across visible to near-infrared wavelengths.

Conclusions:

• Optimized RF sputtering and annealing are effective for fabricating low-loss GeO2 thin-film optical waveguides.
• GeO2 thin-film waveguides exhibit excellent optical properties suitable for broad wavelength applications.
• These findings support the use of GeO2 in advanced photonic devices.