Lasing characteristics of 0.8-μm InGaAsP/GaAs lasers fabricated by wet chemical etching

Abstract

0.8-μm InGaAsP/GaAs stripe lasers, in which cavity mirrors were formed by two-step wet chemical etching, have been fabricated monolithically. The laser resonators were aligned along the 〈011̄〉 and the 〈010〉 directions. The first etching was done in 5% Br methanol. The secondary etching was done in H2SO4:H2O2:H2O (3:1:1 by volume) etchant for the active layers only, and gave low threshold lasers. Their threshold current densities were compared with those of the cleaved-mirror lasers made from the same wafer. Some longitudinal lasing modes were observed in the wavelength range of 805–810 nm. The characteristic temperature T0 was 116 K in the temperature range 28–87 °C. The relationship between the state of the etched facets and the near- and far-field patterns was examined. It was found that this two-step etching technique for the laser mirrors is very suitable for aligning the lasers along desirable directions on the same wafer for monolithic integrated optical circuits.