Novel current-blocking structures in semiconductor lasers using directly bonded InP-SiO2-InP

We propose a novel laser structure that uses a SiO₂ insulator sandwiched with InP as a current blocking layer. The structure has been successfully fabricated using a direct bonding technique. A 1.3-μm InGaAsP laser with a bulk active layer and a 300-μm cavity achieved a threshold current density of 1.9 kA/cm² and a maximum output power of 60 mW. Which implies that the leakage current is negligible. The parasitic capacitance has been measured to be 30 pF even for a laser with an area of 300 μm×300 μm.