Abstract: A resonant-periodic-gain distributed-feedback surface-emitting semiconductor laser has a resonator with an axis perpendicular to the plane of the substrate. The resonator comprises a stack of distributed feedback elements, each consisting of a spacer region and a very thin gain element positioned at an antinode of a standing wave inside the resonator at a designed wavelength. Each gain element consists of one or a group of closely spaced quantum-well layers. Each spacer, separating two adjacent gain elements, consists of two intermediate-and low-refractive-index layers, each layer of the spacer having an optical thickness approximately equal to a quarter of the designed wavelength. The refractive index of each of the gain elements is higher than that of the spacer materials. The device can be surrounded by a material of refractive index lower than all materials comprising the device for better confinement of carriers and control of guided modes of radiation.

Abstract: A wavelength resonant semiconductor gain medium is disclosed. The essential feature of this medium is a multiplicity of quantum-well gain regions separated by semiconductor spacer regions of higher bandgap. Each period of this medium consisting of one quantum-well region and the adjacent spacer region is chosen such that the total width is equal to an integral multiple of 1/2 the wavelength in the medium of the radiation with which the medium is interacting. Optical, electron-beam and electrical injection pumping of the medium is disclosed. This medium may be used as a laser medium for single devices or arrays either with or without reflectors, which may be either semiconductor or external.