Fabrication and optimization of 1.55-μm InGaAsP/InP high-power semiconductor diode laser

A comprehensive design optimization of 1.55-μm high power InGaAsP/InP board area lasers is performed aiming at increasing the internal quantum efficiency (η_i) while maintaining the low internal loss (α_i) of the device, thereby achieving high power operation. Four different waveguide structures of broad area lasers were fabricated and characterized in depth. Through theoretical analysis and experiment verifications, we show that laser structures with stepped waveguide and thin upper separate confinement layer will result in high η_i and overall slope efficiency. A continuous wave (CW) single side output power of 160 mW was obtained for an uncoated laser with a 50-μm active area width and 1 mm cavity length. (paper)