High-power semiconductor laser with a narrow linewidth based on transverse photonic crystal

Area of Science:

• Photonics
• Semiconductor Lasers
• Optical Engineering

Background:

• Broad-area lasers (BA) offer high output power but suffer from linewidth broadening due to high-order mode excitation at high currents.
• Achieving narrow linewidth and high power simultaneously in BA lasers remains a challenge for advanced optical applications.

Purpose of the Study:

• To demonstrate an electrically-pumped broad-area laser with narrow linewidth and high power emission.
• To achieve single-lateral and single-longitudinal mode operation using mode engineering techniques.

Main Methods:

• Utilized mode engineering with double-side transverse photonic crystals (TPCs) and a longitudinal high-order surface grating.
• Expanded the effective volume of high-order modes via TPC band matching, while preserving the fundamental mode.
• Implemented selective pumping and a 27-order grating for single-lateral and single-longitudinal mode control.

Main Results:

• Achieved single-lateral and single-longitudinal mode operation.
• Demonstrated an output power of 115 mW at a lasing wavelength of 1552.94 nm.
• Obtained a narrow linewidth of 443 kHz, SMSR of 59.26 dB, and RIN < -135 dB/Hz at 600 mA.

Conclusions:

• The developed laser design effectively suppresses high-order modes, enabling narrow linewidth and high power.
• The device's performance makes it suitable for demanding applications such as coherent optical communication and LiDAR.
• The use of I-line lithography offers a practical fabrication route for such advanced lasers.