Direct generation of sub-picosecond pulse via multi-section gain switching

Area of Science:

• Optics and Photonics
• Semiconductor Lasers
• Ultrafast Lasers

Background:

• Conventional gain switching in single-section semiconductor lasers often produces optical pulses with undesirable low-energy tails and chirp.
• Direct generation of short optical pulses is crucial for various applications in spectroscopy, telecommunications, and material processing.

Purpose of the Study:

• To directly generate ultrashort optical pulses with suppressed low-energy tails and chirp.
• To investigate the effectiveness of multi-section semiconductor laser gain switching for short-pulse generation.

Main Methods:

• Directly generated optical pulses using gain switching of multi-section semiconductor lasers.
• Optimized the lengths of absorption (50 µm) and gain (200 µm) regions.
• Conducted experiments using impulsive optical pumping at low temperatures.

Main Results:

• Successfully generated optical pulses with a duration of 0.56 picoseconds (ps).
• Achieved a peak power of 25 Watts (W).
• Observed suppression of the low-energy tail and chirp compared to single-section lasers.

Conclusions:

• Multi-section gain switching is a viable technique for direct generation of short optical pulses.
• Optimized multi-section laser design effectively minimizes pulse imperfections.
• This method offers a promising approach for producing high-quality ultrashort laser pulses.