Broadband chaos generation in a distributed-feedback laser by selecting residual side modes

Area of Science:

• Optics and Photonics
• Laser Physics
• Nonlinear Dynamics

Background:

• Distributed-feedback (DFB) lasers typically operate in a single mode.
• Generating broadband chaotic dynamics often involves complex multimode interactions.
• Controlling laser dynamics for specific applications requires precise spectral manipulation.

Purpose of the Study:

• To experimentally generate broadband chaotic dynamics in a DFB laser.
• To achieve spectral broadening by selectively exciting a residual side mode.
• To explore a simplified approach for chaos generation without multimode interactions.

Main Methods:

• Utilizing a fiber Bragg grating (FBG) to provide feedback to a residual side mode of a DFB laser.
• Suppressing the main mode emission through selective FBG feedback.
• Characterizing the spectral and electrical bandwidth of the generated chaotic output.

Main Results:

• Broadband chaotic dynamics were successfully generated by exciting a single residual side mode.
• The chaotic output exhibited an electrical bandwidth exceeding 26 GHz, a >50% spectral broadening.
• The generated chaos was attributed solely to the dynamics of the selected mode, avoiding multimode effects.
• Wavelength tunability exceeding 10 nm was demonstrated using different FBGs.

Conclusions:

• Selective excitation of a residual side mode is an effective method for broadband chaos generation in DFB lasers.
• This approach simplifies modeling and offers potential for various applications due to its controlled nature.
• The technique provides a tunable source of broadband chaotic light without complex multimode dynamics.