Abstract: A method for dynamically reconfiguring control of a data bus when an initial device acting as a bus master fails or become inoperative. Each device connected to the data bus checks for the logical address of either its next higher or next lower neighbor; and the initial device acting as bus master is arbitrarily assigned the highest or lowest available logical address respectively. In either instance, the logically next lower or logically next higher device, respectively, may see a device at a logical address that is lower or higher than its own, thereby indicating that the initial device acting as bus master has become inoperative. Thereafter, the next available device able to act as bus master promotes itself to act as bus master, including reassigning itself to the highest or lowest available logical address, respectively.

Abstract: A quaternary semiconductor diffraction grating, such as an InGaAsP grating suitable for a DFB laser, is embedded in a semiconductor substrate, such as InP. In one embodiment, the grating is fabricated by(1) forming on the top surface of an InP substrate body an epitaxial layer of InGaAsP coated with an epitaxial layer of InP;(2) forming a pattern of apertures penetrating through the layers of InP and InGaAsP; and(3) heating the body to a temperature sufficient to cause a mass transport of InP from the InP epitaxial layer, the thickness of the InP layer being sufficient to bury the entire surface of the InGaAsP layer with InP.

Abstract: Proposed is a method of fabricating semiconductor devices involving vapor etching of channels and/or growth of layers in a substrate. The etch or growth rate is controlled by opening up additional regions in the mask which are separated from the opening used to define the active region. The etching or growth in the additional exposed regions of the substrate consumes a certain amount of reactant and controllably reduces the amount available for etching or growth in the active region.