Tawee Tanbun-Ek

Fabrication and lasing properties of mesa substrate buried heterostructure GaInAsP/InP lasers at 1.3 µm wavelength

Fabrication and lasing properties of novel GaInAsP/InP injection lasers at 1.3 μm, with buried heterostructure grown on mesa substrate and fabricated by single-step crystal growth are reported. In this mesa substrate buried heterostructure (MSB) laser, the GaInAsP active layer was grown separately on the top of a mesa structure formed along the surface of a

1.6 µm Wavelength Buried Heterostructure GaInAsP/InP Lasers

GaInAsP/InP buried heterostructure lasers with anti-melt back layer emitting at 1.6 µm wavelength were fabricated and operated in a single mode in cw condition at room temperature. The gain suppression in spontaneously emitting resonant modes due to the lasing mode was found out, and it was significantly larger than that in lightly doped GaAs/AlGaAs DH lasers.

1.6 µm wavelength GaInAsP/InP BH lasers

1.6μm wavelength GaInAsP/InP buried heterostructure (BH) lasers were fabricated by the LPE technique using an antimeltback layer. A new fabrication process was used in order to prevent thermal damage of the etched wafer for second growth and to promote smooth growth. The low threshold current of 23 mA was obtained for a cavity length of approximately 300μm and a stripe width of3-5\mum. Transverse single-mode operation up to more than three times the threshold was obtained. Room temperature CW operation was also obtained with a threshold current of 28 mA and a differential quantum efficiency of approximately 30 percent. Temperature dependences of threshold current and differential quantum efficiency were measured and explained taking account of intervalence band absorption loss due to the split-off band.

Static characteristics of 1.5 - 1.6 µm GaInAsP/InP buried heterostructure butt-jointed built-in integrated lasers

Lasing characteristics of GaInAsP/InP buried heterostructure butt-jointed built-in distributed Bragg reflector integrated lasers (BH-BJB-DBR lasers) intended for dynamic single mode operation in the wavelength range of1.5-1.6 \mum are given. In the first section, the coupling property between the active region and the butt-jointed external waveguide region is calculated to show the possibility of large fabrication tolerance. A coupling coefficient of more than 95 percent is estimated. Secondly, the GaInAsP/InP integrated lasers were fabricated and tested in the view of the static characteristics and the axial mode selection property. Lateral mode control was achieved by the use of a buried heterostructure, so that the axial and lateral modes were maintained to a fixed single mode. The lasers thus fabricated were operated in CW conditions at room temperature with a threshold current of about 100 mA. Single longitudinal mode operation was observed with a temperature dependence of about 0.13 nm/deg with the temperature range of more than50-65\degC at around 0°C. Differential quantum efficiency as high as 13 percent/ facet was obtained for the laser with power output of more than 5 mW/facet. The output spectrum below threshold indicated the strong wavelength selectivity of the DBR region, and the net gain difference between the main DBR mode and the adjacent submode was measured to be about 6 cm-1. No appreciable degradation and change of characteristics have been observed even after CW operation of more than 9770 h at 20°C.