Dynamics of a short cavity swept source OCT laser

Area of Science:

• Laser physics
• Nonlinear dynamics
• Optical engineering

Background:

• Swept source lasers are crucial for applications like optical coherence tomography.
• Understanding their complex dynamics, including mode-hopping and chaos, is essential for performance optimization.
• Intra-cavity filters significantly influence laser behavior.

Purpose of the Study:

• To experimentally and theoretically investigate the dynamics of a short cavity swept source laser with an intra-cavity swept filter.
• To characterize distinct operational regimes such as mode-hopping, frequency sliding mode-locking, and chaos.
• To analyze the impact of filter width on laser performance and its implications for optical coherence tomography (OCT).

Main Methods:

• Real-time intensity measurements using a fast digital oscilloscope.
• Development and application of a delay differential equation model.
• Theoretical analysis of mode-locking parameters and linewidth variations.

Main Results:

• Experimental and theoretical results show close agreement, validating the proposed model.
• Identified distinct operational regimes including mode-hopping, frequency sliding mode-locking, and chaos.
• Demonstrated that increasing filter width enhances maximum sweep speed but broadens the instantaneous linewidth.

Conclusions:

• The developed delay differential equation model accurately describes the laser's behavior.
• Optimizing filter width allows tuning of sweep speed and linewidth trade-offs for specific applications.
• Findings provide insights for enhancing swept source laser performance in optical coherence tomography.