Bifurcation scenarios for chirped mode locking in a semiconductor laser

Area of Science:

• Physics
• Optics
• Nonlinear Dynamics

Background:

• Semiconductor lasers are crucial for modern optics and photonics.
• Mode-locking is essential for generating ultrashort optical pulses.
• Understanding laser dynamics, especially with normal dispersion, is key for advanced applications.

Purpose of the Study:

• To investigate novel bifurcation scenarios in two-section semiconductor lasers.
• To identify conditions leading to stable mode-locked operation with normal dispersion.
• To characterize the resulting pulse properties and parameter space.

Main Methods:

• Utilized a delay differential equation model for a two-section semiconductor laser.
• Analyzed bifurcation scenarios to find new operational regimes.
• Mapped the parameter space defining the observed phenomenon.

Main Results:

• Identified a new bifurcation scenario leading to stable mode-locking.
• Observed normal dispersion properties in the light travel.
• Characterized asymmetric pulse profiles with a slower leading edge and negative chirp.
• Defined the parameter space as a Busse balloon.

Conclusions:

• A novel route to stable mode-locked semiconductor lasers with normal dispersion has been found.
• The identified regime exhibits unique asymmetric pulse characteristics.
• The Busse balloon provides a framework for understanding the parameter space of this operation.