Femtosecond laser fabricated semi-tapered waveguide for Q-switched vortex laser generation

Area of Science:

• Photonics and Optical Engineering
• Materials Science
• Laser Physics

Background:

• Dielectric waveguides are crucial for integrated photonic circuits due to strong optical confinement.
• Developing advanced waveguide structures is key for next-generation photonic devices.
• Femtosecond laser direct writing offers precise fabrication for complex optical components.

Purpose of the Study:

• To design and fabricate a novel semi-tapered depressed-cladding waveguide.
• To analyze the optical guiding performance and loss characteristics of the new waveguide.
• To demonstrate the potential of this platform for integrated pulsed lasers, specifically vortex lasers.

Main Methods:

• Fabrication of a semi-tapered depressed-cladding waveguide using femtosecond laser direct writing.
• Systematic optical characterization, including loss analysis.
• Integration with an Sb2Te3 thin film as a saturable absorber to achieve Q-switched operation.

Main Results:

• Successful demonstration of an efficient vortex waveguide laser.
• Achieved stable Q-switched vortex laser operation with short pulse duration and high repetition rate.
• Validated the high gain and superior laser performance of the semi-tapered waveguide platform.

Conclusions:

• The novel semi-tapered waveguide platform is suitable for high-performance integrated photonic devices.
• This technology enables the development of compact and efficient on-chip pulsed lasers.
• The study highlights the potential for 3D waveguides in advanced laser applications.