Planar buried heterostructure GaInAsP/AlGaAs visible lasers emitting at 674 nm in wavelength fabricated for the first time and operated under room temperature pulse condition. The low threshold current of 80 mA and the output power of 5 mW/facet were obtained.

This paper gives an experimental result on the measurement of the maximum coupling coefficient and the coupling length between the active waveguide and the passive output waveguide in GaAs/AlGaAs integrated twin-guide (ITG) injection lasers prepared by LPE. Very high coupling efficiency between the active and the passive waveguides was experimentally confirmed. The maximum coupling coefficient and the coupling length were measured to be about 90% and 250 µm, respectively. These values were in agreement with theory. At properly chosen parameters, the threshold current density on an ITG-type" laser was as low as 3 kA/cm2 at room temperature.