Enhanced modulation characteristics in broken symmetric coupled microring lasers

Area of Science:

• Optics and Photonics
• Quantum Electronics
• Semiconductor Lasers

Background:

• Coupled cavity lasers are crucial for advanced photonic applications.
• Understanding their dynamical behavior under modulation is essential for performance optimization.
• Broken symmetry offers novel routes to tailor laser characteristics.

Purpose of the Study:

• To theoretically investigate the dynamical behavior of broken symmetric coupled cavity lasers.
• To analyze the frequency response under direct modulation.
• To explore modulation bandwidth enhancement in parity-time (PT) symmetry and non-PT symmetry domains.

Main Methods:

• Small signal analysis was employed to derive the frequency response.
• Theoretical predictions were numerically examined using an InGaAs quantum dot laser system.
• The study focused on the influence of injection current and gain-loss contrast.

Main Results:

• A modulation bandwidth enhancement was predicted for broken symmetric lasers.
• The numerical simulations confirmed the theoretical findings in the InGaAs quantum dot platform.
• Both injection current and gain-loss contrast were identified as key control parameters.

Conclusions:

• Broken symmetric lasers exhibit enhanced modulation bandwidth.
• Gain-loss contrast provides an additional degree of freedom for controlling laser frequency response poles.
• This research offers new insights for designing high-performance semiconductor lasers.