Fabrication of high power 1.5†µm wavelength InGaAsP/InP BH lasers having dilute waveguide structure.

1.5 µm wavelength high power buried heterojunction (BH) semiconductor lasers having dilute waveguide structure have been fabricated. The optical field is dragged down toward the n side of the device by the dilute waveguide layer, lowering the optical confinement factor of the p doped material and active material, which helps to enlarge the laser output light power. Compared with thick InGaAsP cladding layer, the dilute waveguide material is easy to be grown and has higher thermal conductivity. The slope efficiency of the obtained dilute waveguide BH lasers is notably higher than that of the BH lasers having no dilute waveguide. Our studies show that the dilute waveguide structure is promising for the fabrication of high power BH lasers.

Slotted surface gratings fabricated by selective area growth of the p-InP cladding layer for BH lasers.

In this paper, we present a novel, to our knowledge, method for the fabrication of slotted surface gratings for buried heterostructure (BH) lasers. In the device fabrication process, SiO2 strips needed for InP current blocking layer growth are reused for the formation of slot grating pattern masks. In the following growth of the p-InP cladding layer, because the slot areas are covered by SiO2, the InP material is grown selectively in only the areas outside the slot areas, forming slots of the surface gratings in the p-InP layer at the same time as the cladding layer growth. Single longitude mode BH lasers having slotted surface gratings have been fabricated successfully, and the spectra show higher than 40 dB side mode suppression ratio (SMSR). The adoption of the method helps to simply the device fabrication and thus lower the device fabrication cost notably.