Hybrid glass substrates for waveguide device manufacture

Area of Science:

• Materials Science
• Optoelectronics
• Photonics

Background:

• Traditional methods for fabricating integrated optical devices often involve complex, high-temperature processes.
• Developing robust, versatile substrates is crucial for advancing integrated photonics and laser technologies.
• Combining active (gain) and passive (waveguide) materials on a single substrate presents fabrication challenges.

Purpose of the Study:

• To develop a novel, low-temperature process for creating hybrid glass substrates.
• To enable simultaneous waveguide fabrication in both active and passive glass regions.
• To demonstrate the performance of a hybrid laser waveguide device.

Main Methods:

• A low-temperature process was employed to join active (Erbium-Ytterbium codoped) and passive phosphate glass.
• The resulting hybrid substrates were subjected to conventional, water-based cutting, grinding, and polishing.
• Waveguides were fabricated simultaneously in active and passive regions by immersing the substrate in a molten-salt bath.
• Optical low-coherence reflectometry was used to measure interface reflectance.
• A hybrid laser waveguide device was tested for slope efficiency.

Main Results:

• The hybrid substrates exhibited excellent chemical and physical robustness, compatible with standard processing techniques.
• A low interface reflectance of -34+/-2 dB was achieved at 1531.2 nm.
• The hybrid laser waveguide device demonstrated a significant slope efficiency of 33% at 1540 nm when pumped at 975 nm.

Conclusions:

• The novel low-temperature process successfully created robust hybrid glass substrates.
• Simultaneous waveguide fabrication in active and passive regions is feasible.
• The demonstrated hybrid laser waveguide device shows promising performance for integrated photonic applications.