Lateral divergence angle reduction of semiconductor lasers with loss-enhanced supersymmetric structure

Area of Science:

• Optics and Photonics
• Semiconductor Lasers

Background:

• Supersymmetric lasers offer unique properties but can suffer from wide far-field divergence.
• Maintaining a narrow horizontal far-field (HFF) divergence angle at high output powers is crucial for many applications.

Purpose of the Study:

• To propose and fabricate a loss-enhanced supersymmetric semiconductor laser.
• To investigate the impact of a loss-enhanced slot (LE-slot) on laser performance, particularly HFF divergence.

Main Methods:

• Introduction of a LE-slot into supersymmetric waveguide arrays.
• Fabrication of the proposed laser device.
• Characterization of output power and HFF divergence angle at various injection currents.

Main Results:

• The LE-slot successfully increased the lasing threshold of unwanted modes.
• A quasi-single-lobed HFF distribution was achieved at 0.5 A with 200 mW output power.
• At 1.5 A, the laser delivered 692 mW with a HFF divergence angle FWHM of 1.5°, significantly outperforming devices without the LE-slot.

Conclusions:

• The LE-slot is an effective method for controlling HFF divergence in supersymmetric semiconductor lasers.
• This approach enables high-power operation while maintaining a narrow HFF divergence angle.
• The developed laser shows significant advantages for applications requiring high power and precise beam control.