High power 1060-nm super large vertical cavity semiconductor lasers

Abstract

High power single-mode ridge waveguide 1060-nm semiconductor lasers are reported. The lasers consist of compressively strained double InGaAs/GaAs quantum wells and a GaAs/AlGaAs separate confinement vertical structure. A super large vertical optical cavity is employed to have a low internal loss, large optical spot size and low vertical optical divergence angle. The material composition and thickness of waveguide layers and claddings layer are optimized systematically. The active layer is detuned from center of the waveguide and thickness of cladding layers is optimized to guaranty single mode lasing of the large optical cavity. The large vertical cavity laser structure with thickness of 4 μm allows the lasers have a low internal loss of less than 0.6 /cm, a large optical spot size about 1μm and a vertical divergence angle about 20 degree. For lateral optical confinement, a double trench ridge waveguide is employed to maintain single-lateral-mode operation. Based on the optimization, 1.5 W continue wave optical power is achieved for broad area lasers with 1mm longitude cavity length. Narrow stripe ridge waveguide lasers of 1mm cavity length with single mode current and optical power of 700 mA and 340 mW is obtained. Suggestions for further improvements in terms of single mode power and applications of the high power semiconductors are discussed.