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Gain-switching dynamics in optically pumped single-mode InGaN vertical-cavity surface-emitting lasers
Optics Express
|March 26, 2014
Summary
Researchers studied blue Indium Gallium Nitride (InGaN) vertical-cavity surface-emitting lasers (VCSELs), achieving 6.0 ps single-mode pulses. These findings suggest subpicosecond pulses are achievable with optimized device parameters.
Area of Science:
- Semiconductor Lasers
- Quantum Well Technology
- Optoelectronics
Background:
- Vertical-cavity surface-emitting lasers (VCSELs) are crucial for optical communications.
- Blue InGaN-based VCSELs offer potential for shorter wavelength applications.
- Understanding gain-switching dynamics is key to optimizing pulse generation.
Purpose of the Study:
- To investigate the gain-switching dynamics of single-mode pulses in blue InGaN multiple-quantum-well (MQW) VCSELs.
- To determine the shortest achievable pulse width.
- To analyze the influence of pump power on pulse characteristics.
Main Methods:
- Impulsive optical pumping of blue InGaN MQW VCSELs.
- Up-conversion method for measuring ultrashort pulse widths.
- Streak-camera measurements to analyze pulse width and delay time.
- Single-mode rate-equation calculations for theoretical analysis.
Main Results:
- The shortest single-mode pulse width measured was 6.0 picoseconds (ps).
- Pulse width and delay time were characterized as functions of pump power.
- Rate-equation calculations accurately reproduced experimental observations.
- Modal gain was identified as the primary factor limiting pulse width.
Conclusions:
- The study successfully characterized gain-switching dynamics in blue InGaN VCSELs.
- Experimental results were quantitatively validated by theoretical calculations.
- Subpicosecond pulse generation is feasible within current device parameters, indicating potential for future advancements.
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