Nonlinear dynamics of a coupled twin-waveguide semiconductor laser with surface gratings

Area of Science:

• Optics and Photonics
• Semiconductor Lasers
• Nonlinear Dynamics

Background:

• Semiconductor lasers are crucial for optical communication and signal processing.
• Achieving controllable nonlinear dynamics in semiconductor lasers is essential for advanced applications.
• Existing methods often lack tunability and on-chip integration.

Purpose of the Study:

• To propose and demonstrate a novel coupled twin-waveguide semiconductor laser.
• To achieve controllable nonlinear dynamics, including chaotic oscillations.
• To enable on-chip generation of complex optical signals.

Main Methods:

• Utilizing high-order slotted surface gratings as active distributed Bragg reflectors.
• Engineering mode coupling and carrier diffusion between twin waveguides.
• Tuning mode frequency difference and relaxation oscillation frequency via injection currents.

Main Results:

• Demonstrated controllable dynamic states: periodic, quasiperiodic, and chaotic oscillations.
• Generated chaotic optical signals with inherent randomness.
• Achieved a maximum effective chaotic bandwidth exceeding 11 GHz with 8.4 dB flatness.

Conclusions:

• The proposed laser design enables versatile nonlinear dynamics generation.
• The device is fabricated using standard photolithography and regrowth-free processes.
• This work paves the way for on-chip mode engineering for tailored lasing actions.