Effects of n-type modulation-doping barriers and a linear graded-composition GaInAsP intermediate layer on the 1.3μm AlGaInAs∕AlGaInAs strain-compensated multiple-quantum-well laser diodes

Abstract

We report the fabrication, characterization, and comparison of four 1.3μm AlGaInAs∕AlGaInAs strain-compensated multiple-quantum-well (SC-MQW) laser structures: (1) sample A—with only an undoped SC-MQW active region, (2) sample B—with an undoped SC-MQW active region and a linear graded-composition (LGC) GaInAsP intermediate layer, (3) sample C—with an n-type modulation-doping (MD) SC-MQW active region, and (4) sample D—with an n-type MD-SC-MQW active region combined with a LGC GaInAsP intermediate layer. The inclusion of either n-type modulation-doped SC-MQW active region or LGC GaInAsP intermediate layer can improve the performance of a laser diode (LD). The LD sample D, which includes both an n-type MD-SC-MQW active region and a LGC GaInAsP intermediate layer, exhibits the best overall performance including a threshold current of 12.5mA, a characteristic temperature of 85K in 20–80°C temperature range, a lasing wavelength shift of 0.38nm∕K, and a relaxation frequency response of 9.9GHz.