electrically pumped solid state laser with fordelad aterkoppling.

摘要

1513573 Semiconductor Lasers XEROX CORP 13 May 1975 [22 Aug 1974] 20027/75 Headings H1C, H1K In a heterostructure semiconductor laser, the need for resonator reflections is avoided by producing Bragg scattering feedback from a periodic grating forming a heteroboundary 5, Fig. 1alpha, of the light waveguide region 2, the spacing of the grating perturbations being an integral number of half wavelengths of the generated radiation. In addition to the conventional laser output obtained in the plane of the waveguide region, lower order Bragg scattering radiation may also be emitted from one or both major surfaces of the semiconductor. As shown in Fig. 1, a single heterostructure laser comprises an n-type GaAs substrate 1 on which the periodic grating is formed by interferometric exposure of a photoresist material to a divided beam from an argon laser, followed by ion implantation, ion milling, diffusion, etching or surface milling. A p-type layer 3 of GaAPAs and a p-type layer 4 of GaAs are then successively deposited by liquid phase epitaxial growth. Subsequently the zine p-type dopant is driven into the substrate to form a p-n junction 6 and the light waveguide region 2 by heating in an evaporated diffusion capsule. Electrodes 7 and 8 of tin and gold, and of titanium, platinum and gold, respectively, are applied by sputtering and annealing. A double heterostructure laser is shown in (Fig. 4) which is similar to Fig. 1 but with an additional layer 10 of n-type GaAPAs providing a p-n function 6 and a second heteroboundary for a GaAs light waveguide region 2. During manufacture this region is doped with germanium or is initially undoped. The p-type dopant may be zine or cadmium.