Abstract: A vertical cavity surface emitting laser (VCSEL) module includes a substrate provided with an etched region formed on a lower surface thereof, a plurality of layers, for photoproduction, laminated on an upper surface of the substrate, and a VCSEL for emitting the light upwards and downwards, wherein the VCSEL module monitors the output of the VCSEL by detecting the light emitted downwards from the VCSEL.

Abstract: A coupling structure for coupling an optical waveguide and an optical device is provided. The coupling structure enables to precisely align the optical waveguide and the optical device so that an optical-alignment error can be reduced within a range of a few &mgr;m. The coupling structure includes a first substrate, at least one optical waveguide formed on the first substrate to transmit an optical signal, optical alignment dummy waveguides symmetrically aligned on the first substrate about the optical waveguide, a second substrate bonded to the first substrate, at least one optical device mounted on a bottom surface of the second substrate and optically connected to the optical waveguide, and optical-alignment patterns formed at the bottom surface of the second substrate corresponding to the optical alignment dummy waveguides, wherein an optical alignment for the optical waveguide and the optical device is achieved by aligning the optical alignment dummy waveguides with the optical-alignment patterns.

Abstract: A vertical cavity surface emitting laser (VCSEL) is provided with an aperture for guiding a flow of electric currents. The aperture is defined by an oxide so that the aperture is formed to be substantially circular in shape. A method for fabricating the laser is also disclosed. The structure of the (VCSEL) makes it possible to control the oxidation rates of an oxidable layer in which an aperture is formed for guiding the flow of electric currents of a VCSEL, by forming a mesa trench of the VCSEL in a segmented structure which has a predetermined number of segments. Accordingly, it is possible to form an aperture approximately in a circular shape, so that the light emitting angle and shape of the VCSEL are easily controlled.