Abstract

Low-threshold single-mode lasers are needed in the integrated optics application. We report here a simple laser structure which has a built-in lateral confinement for both the current and the light. The structure reported here is similar to the conventional Deep Diffused Stripe (DDS) lasers^1,2 but without the need for precise control of diffused dopings as required in the latter. The new structure consists of an n-p-n instead of all n double-heterostructure (DH) layers grown on an n-GaAs substrate. The stripe region is formed by deep Zn diffusion to the p-type active layer with a W-shaped diffusion front (see Fig. 1). The n-p-n structure outside the stripe region automatically forms a reverse-biased junction, while the W-shaped diffusion front provides a lateral refractive-index profile for an optical waveguide.³ With an over-all 6 to 7 μm stripe width, the devices have threshold currents as low as 30 mA. An excellent light-current (L-I) linearity and single-mode operation of these lasers are observed up to about two times their threshold currents. Preliminary results indicate that these lasers also have good modulation characteristics.

© 1982 Optical Society of America