HIGH-PERFORMANCE STRAIN-COMPENSATED MULTIPLE-QUANTUM-WELL PLANAR BURIED HETEROSTRUCTURE LASER-DIODES WITH LOW LEAKAGE CURRENT

The dependence of leakage current in a planar buried heterostructure l aser diode (PBH-LD) on the operating temperature was analyzed by takin g the effects of the connection width between a p-InP clad layer and a p-InP blocking layer into account. A two-step etching process compris ing nonselective mesa etching followed by InP selective etching is pro posed for obtaining a narrow connection width and high controllability of an active layer width. The performance was compared for LDs fabric ated using the two-step etching process and those fabricated using con ventional nonselective etching process. The average threshold current and the slope efficiency of the 1.3 mu m strain-compensated multiple q uantum well (MQW) PBH-LD fabricated using the two-step etching process were 5.6 mA and 0.27 mW/mA, respectively, for a cavity length of 400 mu m. However, using the nonselective etching process, the average thr eshold current was 14.5 mA and the slope efficiency was 0.22 mW/mA, gi ven the same cavity length. A higher differential gain and characteris tic temperature were also obtained due to the lower leakage currents a nd strain-compensated multiple quantum well active layers.