Abstract: There is described an optical radiation sensor device for detecting radiation in a radiation field. The device comprises a sensor element capable of detecting and responding to incident radiation from the radiation field and a radiation window interposed between the sensor element and the radiation field. The radiation window comprises a non-circular (preferably square) shaped radiation transparent opening. The optical radiation sensor device can be used in a so-called dynamic manner while mitigating or obviating the detection errors resulting from the use of a circular-shaped attenuating aperture and/or angular (even minor) misalignment of the sensor device with respect to the array of radiation sources when multiple such circular-shaped attenuating apertures are used.

Abstract: A semiconductor device such as a buried heterostructure semiconductor laser includes a semiconductor substrate supporting an active region comprised of a multiple quantum well active region and confinement layers having defined gratings and grating overgrowth regions to produce a laser device. The device also includes a current confinement layer including a sequence of doped n-p-n-p semiconductor layers to produce a n-p-n-p blocking structure and a semi-insulating semiconductor material deposited over the n-p-n-p blocking structure.

Abstract: A semiconductor device such as a buried heterostructure semiconductor laser includes a semiconductor substrate supporting an active region comprised of a multiple quantum well active region and confinement layers having defined gratings and grating overgrowth regions to produce a laser device. The device also includes a current confinement layer including a sequence of doped n-p-n-p semiconductor layers to produce a n-p-n-p blocking structure and a semi-insulating semiconductor material deposited over the n-p-n-p blocking structure.

Abstract: A method of etching of indium phosphide (InP) semiconductor materials using methyl chloride CH.sub.3 Cl and phosphine PH.sub.3 in a low pressure MOCVD reactor is provided. Etching of InP using CH.sub.3 Cl as an etchant and PH.sub.3 to prevent thermal decomposition of the etched surface gives excellent etching morphology, and a maximum etching rate of 0.75 mm/hr for the CH.sub.3 Cl flow rates studied. A PH.sub.3 flow rate.ltoreq.40 SCCM and etching temperature.gtoreq.610.degree. C. provided excellent etch morphology, without formation of pits, independent of the CH.sub.3 Cl flow rate. A controllable etching rate was obtained for a coated susceptor when deposits are primarily InP. Thus this method of CH.sub.3 Cl etching is suitable for multiple growth and etching steps using an MOCVD reactor. By controlling the PH.sub.

Abstract: In a method for Liquid Phase Epitaxy (LPE) of semi-insulating InP, a solution of P, Ti and a p-type dopant in molten In is cooled in a non-oxidizing ambient at a surface of a substrate to grow an epitaxial layer of doped InP on the surface. The concentration of p-type dopant in the solution is such as to provide a concentration of p-type dopant in the grown epitaxial layer greater than the aggregate concentration of any residual contaminants in the grown epitaxial layer, and the concentration of Ti in the solution is such as to provide a concentration of Ti in the grown epitaxial layer greater than the concentration of p-type dopant in the grown epitaxial layer. The required melt concentrations are determined empirically. The method can be performed at temperature below 650 degrees Celsius and is particularly suited to the LPE growth of semi-insulating InP to isolate InP-InGaAsP buried heterostructure lasers.