Abstract

In the search for an efficient optical source compatible with the monolithic fabrication of integrated optical devices, much attention has been given to the use of gratings to produce the required feedback, instead of the cleaved edges of the discrete double heterostructure (DH) laser, Recently, Hurwitz et al.⁽¹⁾ reported on an alternative approch, utilizing etched mirrors to provide feedback; output from the Fabry-Perot resonator was coupled directly into a thick (12μm) waveguide. We have examined numerous masking and etching procedures and crystal orientations to produce laser mirrors by wet chemical etching. In these experiments, the devices were evaluated by measuring the output radiation from the etched mirrors directly into air; differential quantum efficiencies (η_d) as high as 18% have been achieved (η_d ≃ 10% is routine) as well as room temperature threshold current densities (J_t) as low as 4.2 kA/cm². This represents a significant improvement over earlier published results.⁽¹⁾

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