Tunable Narrow-Linewidth Si₃N₄ External-Cavity Semiconductor Laser Based on an Asymmetric Bezier Triple-Ring...

Area of Science:

• Photonics and Optical Engineering
• Integrated Optics
• Laser Technology

Background:

• Conventional external cavity ring resonators face challenges with high bending loss, limited quality factors, and footprint-loss trade-offs.
• Smoother mode evolution and reduced bend loss are critical for improving resonator performance.

Purpose of the Study:

• To present an AI-assisted design for a tunable narrow-linewidth external cavity laser.
• To overcome limitations of traditional ring resonators by introducing asymmetric Bezier waveguide bends.
• To enhance mode-selection and filtering performance using a cascaded triple-ring resonator structure.

Main Methods:

• Utilized asymmetric Bezier waveguide bends to minimize bending losses.
• Employed particle swarm optimization (PSO) to optimize the Bezier bends.
• Constructed a triple-ring-coupled external cavity for improved mode selection.
• Performed simulations to evaluate resonator performance and laser linewidth.

Main Results:

• The optimized asymmetric Bezier resonator effectively reduced cavity loss.
• Achieved an improved resonator quality factor with a compact device footprint.
• Theoretical analysis predicted a narrow laser linewidth of approximately 390 Hz.
• Demonstrated enhanced mode-selection capability and filtering performance.

Conclusions:

• The proposed AI-assisted design offers a feasible approach for high-performance, low-loss, narrow-linewidth integrated lasers.
• The asymmetric Bezier cascaded triple-ring resonator is significant for advancing integrated photonic laser sources.
• This work paves the way for more efficient and compact laser designs in integrated photonics.