High-brightness supersymmetric transversally coupled stepped-tapered laser diode

Area of Science:

• Optics and Photonics
• Semiconductor Device Physics

Background:

• Semiconductor lasers are crucial for various applications.
• Enhancing output power and brightness in semiconductor lasers remains a key challenge.
• Higher-order mode competition can degrade laser performance.

Purpose of the Study:

• To introduce a novel laser diode configuration for simultaneous enhancement of output power and brightness.
• To suppress transverse higher-order mode competition.
• To improve the spatial overlap between gain and optical fields.

Main Methods:

• Development of a supersymmetric transversally coupled stepped-tapered laser diode (STC-STLD) structure.
• Separate confinement of carriers and optical fields.
• Utilizing a passive supersymmetric transversally coupling structure to manage higher-order modes.
• Employing a stepped-taper design for lateral carrier confinement and mode overlap optimization.

Main Results:

• Achieved 4.6 W output power at 4.4 A drive current under continuous wave (CW) operation.
• Demonstrated exceptional lateral brightness of 6.2 W·mm^-1·mrad^-1.
• Attained a brightness of 149.6 MW·cm^-2·sr^-1.
• Successfully suppressed transverse higher-order mode competition.

Conclusions:

• The STC-STLD configuration effectively enhances both output power and brightness in semiconductor lasers.
• The design allows for wider main waveguides, increasing fundamental mode size and output power.
• The stepped-taper design optimizes carrier distribution for improved mode overlap and laser performance.