Abstract: A method for fabricating a semiconductor device in a semiconductor structure, provides enhanced quantum well intermixing in desired regions of the device by forming a first, relatively high quality, epitaxial layer on a substrate, the high quality layer including a quantum well; forming a second, relatively lower quality, epitaxial defect layer on top of the high quality layer, and thermally processing the structure to effect at least partial diffusion of the defects from the defect layer into the high quality layer in order to achieve quantum well intermixing in the structure. The use of an epitaxially grown defect layer on top of, or within, a high quality epitaxially grown device body enables quantum well intermixing techniques to be performed at lower temperatures and thereby improves device characteristics.

Abstract: An active photonic device includes a semiconductor substrate, an optically active region formed on the semiconductor substrate, the optically active region including a first electrical contact for initiating emission of photons and/or modulation of photons within the optically active region, an optical confinement structure defining a principal optical path through the active photonic device and through the optically active region, and a photodetector structure formed on the semiconductor substrate. The photodetector includes a second electrical contact displaced from, and substantially electrically insulated from, the first electrical contact and overlying at least part of the principal optical path, the photodetector for receiving carriers generated by emitted photons.

Abstract: A method of performing quantum well intermixing in a semiconductor device structure uses a sacrificial part of a cap layer, that is removed after QWI processing, to restore the cap surface to a condition in which high performance contacts are still possible.

Abstract: An optical system for producing an array of single transverse mode laser beam output includes a monolithic laser array (23) having a plurality of outputs (5) in which each laser (4) is adapted for operation so as to produce a single transverse mode output; and an array of waveguides (10), the waveguide array being positioned in relation to the laser array such that each laser output from the laser array couples into an input of a respective waveguide (11) in the waveguide array, the waveguide array maintaining the single transverse mode of each laser output at a respective waveguide output to provide a single transverse mode beam output. Multiple laser arrays (23) be coupled to a single waveguide array (10) enabling the formation of very large arrays and arrays with beam pitch smaller than otherwise possible.

Abstract: An integrated optical device formed in a semiconductor substrate incorporated an integral lens element in the substrate for providing focusing of the output beam. The device includes an optically active region for generating and confining optical radiation and having an output end for emitting an output beam from the optically active region; and a lens region adjacent the output end which has an increased band gap to the adjacent substrate material and is shaped to provide a lens effect on said output beam. The optically active region forms a cavity having a longitudinal axis, and the lens region extends along the longitudinal axis and has a lateral extent that varies as a function of distance along the longitudinal axis.

Abstract: A method of performing quantum well intermixing in a semiconductor device structure uses a sacrificial part of a cap layer, that is removed after QWI processing, to restore the cap surface to a condition in which high performance contacts are still possible.

Abstract: An active photonic semiconductor device, such as a laser, optical amplifier or LED, is monolithically integrated with a photodetector. The device includes an optically active region formed on a substrate including a first electrical contact for initiating emission of photons within the optically active region; an optical confinement structure generally defining a principal optical path through the device and through said optically active region; and a photodetector structure formed on the substrate including a second electrical contact displaced from and substantially electrically insulated from the first contact, overlying a part of the principal optical path, for receiving carriers generated by said emitted photons. The photodetector is preferably positioned to cover an intermixed/non-intermixed region close to a facet of the device and also close to the active region of the device.