High-brightness supersymmetric transversally coupled stepped-tapered laser diode

We present a novel supersymmetric transversally coupled stepped-tapered laser diode (STC-STLD) configuration to simultaneously enhance both output power and brightness in semiconductor lasers. This configuration enables the separate confinement of carriers and optical fields. Higher-order modes expand into the passive supersymmetric transversally coupling structure, which effectively suppresses transverse higher-order mode competition. The integrated coupling structure permits wider main waveguides to increase the fundamental mode size laterally, thereby increasing output power. The stepped-taper design limits the injected carriers in a lateral direction and increases the spatial overlap between the resulting gain distribution with the supported lateral modes optical field distribution. Experimental realization, based on a 980 nm ridge waveguide structure with a cavity length of 4 mm, demonstrates exceptional performance under continuous wave (CW) operation: achieving 4.6 W output power at a 4.4 A drive current with brightness metrics (at second-moment level, ISO 11146-compliant) of 6.2 W·mm^-1·mrad^-1 (lateral brightness) and 149.6 MW·cm^-2·sr^-1.