Integrated short cavity laser with bragg mirrors

Abstract

An edge emitting laser combines many of the desirable attributes of the common forms of surface-emitting and edge-emitting laser structures together with elimination of their drawbacks. The laser cavity of a device according to the present invention is short (on the order of the wavelength of light in the cavity medium) and current is injected into the optical cavity substantially perpendicular to the plane of emitted light and parallel to the plane of reflective mirrors. The use of a short optical cavity permits single mode laser operation because of broad mode to mode spacing and large changes in reflectivity between wavelengths. Injecting current into the cavity perpendicular to the direction of light emission provides low power operation because the resistance associated with the injected current is low. The resistance is low because current does not cross boundaries between the different material layers forming the reflective mirrors and the optical cavity. A groove in the semiconductor substrate is formed which aligns an optical fiber to one edge of the laser device. The formation of an optical device incorporating this laser structure is inexpensive to manufacture because the laser is based on planar semiconductor fabrication techniques and the optical alignment of an optical fiber to the laser has been defined by the groove adjacent the laser device.