Pulse properties of external-cavity mode-locked semiconductor lasers

Area of Science:

• Optics and Photonics
• Semiconductor Lasers
• Ultrafast Optics

Background:

• External-cavity mode-locked semiconductor lasers are crucial for generating ultrashort optical pulses.
• Understanding performance limitations is key to advancing laser technology.

Purpose of the Study:

• To investigate the theoretical and experimental performance of external-cavity mode-locked semiconductor lasers.
• To optimize stable mode-locking and sub-picosecond optical pulse generation.
• To identify factors limiting laser performance.

Main Methods:

• Theoretical analysis using a fully-distributed time-domain model.
• Experimental investigation of laser performance.
• Optimization analysis focusing on stable mode-locking regimes.

Main Results:

• Demonstrated stable output pulses with durations down to one picosecond.
• Achieved more than 30 dB trailing pulse suppression.
• Identified ultrafast gain dynamics as a limiting factor.

Conclusions:

• Ultrafast gain dynamics significantly reduce pulse-shaping strength.
• These dynamics inhibit the generation of femtosecond optical pulses from the investigated laser.
• Further research is needed to overcome these limitations for even shorter pulses.