Abstract: A semiconductor device, formed on a wafer, comprises an array of laser diodes, each emitting a beam parallel to the wafer surface and, integrated with the array, individually tilted deflecting mirrors forming an array of virtual sources. The virtual sources are spaced more closely together than the physical separation of the laser diodes and can even be coincident, thereby reducing the apparent spacing between the beam origins. The reflected beams are substantially perpendicular to the wafer providing a "surface-emitting" device. The required deflector configuration can be fabricated using a single undirectional process, the mirror positions and orientations being determined by proper segment geometry of the etch-mask.

Abstract: A magnetoresistive (MR) read transducer having passive end regions separated by a central active region in which an MR layer is formed which extends over substantially only the central active region and in which a hard magnetic layer is formed in each end region. The hard magnetic layers form an abutting junction having electrical and magnetic continuity with the MR layer to produce a longitudinal bias in the MR sensor. The transducer is produced by a method in which the same stencil defines the extent of both the MR layer and the hard magnetic layers so that the abutting junctions are formed easily and reliably.

Abstract: A method, and device produced therewith, for improving the planarity of etched mirror facets 18 of integrated optic structures with non-planar stripe waveguides, such as ridge or groove diode lasers or passive devices such as modulators and switches. The curvature of the mirror facet surface at the edges of the waveguide due to topographical, lithographical and etch process effects, causes detrimental phase distortions, and is avoided by widening the waveguide end near the mirror surface thereby shifting the curved facet regions away from the light mode region to surface regions where curvature is not critical.

Abstract: A magnetoresistive (MR) read transducer having passive end regions separated by a central active region in which an MR layer is formed which extends over substantially only the central active region and in which a hard magnetic layer is formed in each end region. The hard magnetic layers form an abutting junction having electrical and magnetic continuity with the MR layer to produce a longitudinal bias in the MR sensor. The transducer is produced by a method in which the same stencil defines the extent of both the MR layer and the hard magnetic layers so that the abutting junctions are formed easily and reliably.

Abstract: A magnetoresistive (MR) read transducer comprising an MR layer having passive end regions separated by a central active region. A longitudinal bias is produced by a thin film of hard magnetic material in the end regions only, and the thin film of hard magnetic material is spaced from the MR layer by a nonmagnetic spacer layer so that a magnetostatic longitudinal bias is produced of a level to maintain the passive end regions of the MR layer in a stable state.

Abstract: A magnetoresistive (MR) read transducer assembly in which the thin film MR layer is longitudinally biased only in the passive regions by exchange bias developed by a thin film of antiferromagnetic material that is deposited in direct contact with and continuously covering a thin film of soft magnetic material which extends across the transducer assembly. The longitudinal bias is developed by exchange coupling between the thin film of antiferromagnetic material and both the MR layer and the thin film of soft magnetic material in the passive regions. However, the thin film of soft magnetic material is separated from the MR layer in the active region only of the MR layer by a decoupling layer which interrupts the exchange coupling so that transverse bias is produced only in the active region upon connection of a bias source to conductor leads which are connected to the MR layer within the passive region.

Abstract: A magnetoresistive (MR) read transducer assembly in which the thin film MR layer is longitudinally biased only in the end regions by exchange bias developed by a thin film of antiferromagnetic material that is deposited in direct contact only in the end regions of the MR layer and a thin film of soft magnetic material which extends across the transducer assembly. The longitudinal bias is developed by exchange coupling between the thin film of antiferromagnetic material and both the MR layer and the thin film of soft magnetic material in the end regions. However, the thin film of soft magnetic material is separated from the MR layer in the central region only of the MR layer by a decoupling layer which interrupts the exchange coupling so that transverse bias is produced only in the central region upon connection of a bias source to conductor leads which are connected to the MR layer within the end region.

Abstract: A return-to-zero (RZ) vertical digital magnetic recording method and apparatus comprising a selectively magnetizable recording medium which includes a recording layer of magnetic material having a low vertical remanence. A magnetic recording head is positioned in close proximity to the recording medium, and relative motion is produced between the recording medium and the recording head. To record data, the recording head is energized with one short duration current pulse for each unit of data to be recorded. The resulting bipolar magnetic write field closes substantially perpendicular through the recording medium thereby producing, in the medium, a similarly bipolar flux configuration having the magnetic transition centered about the gap of the magnetic recording head. Data is represented by these transitions in RZ vertical magnetic recording.

Abstract: A magnetic head assembly includes a magnetoresistive (MR) element for reading magnetically recorded information from a record medium. The MR element comprises an elongated member having a predetermined height and a plurality of elongated attachments which are contiguous with and made of the same material as the MR element. The elongated attachments have a predetermined width and a predetermined spacing and the attachments are unidirectionally magnetized along their length so that a bias is produced to maintain the MR sensor in a single domain state and to obtain a substantially linear component in the MR response in the MR element so that Barkhausen noise is suppressed and so that previously recorded information is read from the medium with optimum sensitivity.

Abstract: An MR sensor is disclosed in which a pair of thin film magnetoresistive strips are connected electrically in parallel between two terminals. Strips are spaced apart a distance which is small relative to the density of the stored data to be sensed. The strips are mutually-biased in opposite directions to corresponding points in the linear region of their respective curves by current from a constant source attached to one terminal. Since the resistance of each strip is equal, the current divides equally between the strips.The sensor is positioned adjacent the magnetic surface containing stored data. Vertical components of the magnetic field (preferably vertically recorded data) influence the resistance of the strips differentially. When the sensor encounters a vertical flux transition, the output voltage varies to produce a unimodal type pulse.

Abstract: A permalloy-first bubble switch has two curved propagation elements positioned on a layer of bubble domain supporting material. A curved conductor is superimposed on top of the propagation elements so that a current passing through the conductor element permits a bubble to be moved from one curved propagation element to the second curved propagation element.

Abstract: A parametric bubble detector contains a coupled film sensor stripe and an excitation conductor which, electrically insulated from each other, cross at right angles. A sensor stripe consists of a pair of superpositioned Permalloy stripes which are separated by a thin nonmagnetic layer. A high frequency excitation current in the conductor produces an inductive output signal in the sensor stripe. The waveform of this periodic signal is responsive to bubble domains proximate to the sensor/conductor crossover area.

Abstract: A drive system for a bubble memory consists of a drive assembly and an electrically conducting surface enclosing the drive assembly. In a preferred embodiment, the drive assembly consists of a ferrite picture frame with two pairs of drive coils and the conducting surface is the interior surface of a metallic box.

Abstract: A current access bubble memory system includes a method and device for propagating and switching isolated bubbles within a plurality of orthogonal propagation channels. The device includes two orthogonal arrays of parallel current conductors oriented at 45.degree. angles to the two orthogonal bubble translation axes. The conductors in each array are regularly spaced a distance S apart from center to center. The first array of conductors are connected in parallel to a first current source and the second array of conductors are connected in parallel to a second current source. The propagation channels are defined by confining means to have a width d where d is the bubble diameter. The centerline of the channels are spaced a distance of about .sqroot.2 S/8 from the center of adjacent conductor intersections. Bubble translation occurs through sequential activation of the two bipolar current sources.

Abstract: Field access system for use in propagation of bubbles is disclosed. The field access system combines discrete drive elements with a continuous drive film. An example is a Permalloy overlay consisting of a continuous drive film with protruding T & I bars which function as drive elements. This overlay structure is spaced over a suitable bubble material. The drive film is in direct contact with the T & I drive elements so that exchange coupling exists between the drive film and the drive elements. Use of a continuous drive film allows for control of the drive elements by a closed flux magnetic circuit having low power consumption.

Abstract: Apparatus is provided using as an integral portion thereof a confined array (such as a lattice) of interactive elements, the interactions among which are largely determinative of the positions of the interactive elements since there is a minimum of position determining structure for the elements within the area of confinement. Magnetic elements are suitable interactive elements, and in particular embodiments are shown using magnetic bubble domains. Structure is provided to form lattice arrays of interactive elements, to confine the lattice arrays, and to access elements outside and within the lattice array. In addition, various structures are provided to code the interactive elements for storage of information, and reading devices are provided to detect the information state of the interactive elements when these elements are coded. Various types of lattices and interactive elements can be used.

Abstract: A rotating field access pattern for use in the propagation of a bubble lattice is disclosed. The pattern contains two sets of parallel oblong elements that are substantially perpendicular to each other. Four specific permalloy patterns featuring one element per one, two, two and four bubble domains are shown.

Abstract: A rotating field access pattern for use in the propagation of a bubble lattice is disclosed. The pattern contains a set of diamond shaped magnetic elements arranged in a regular array. The elements have two sides which are parallel to one bubble lattice axis and two sides which are parallel to another bubble lattice axis. The bubbles are propagated in the direction of a third bubble lattice axis.

Abstract: A bubble lattice translation system is disclosed. The system is a combination of two arrays of parallel conductors and confining means. One array of parallel conductors is oriented at an angle of 60.degree. to the lattice translation axis. All of these conductors in this array are connected in parallel to a single current source. The other array of conductors is at an angle of -60.degree. to the lattice translation axis. All of the conductors in the second array are connected in parallel to a second current source. The two conductor arrays exist in the same plane of metallization with no insulation required at conductor intersections. Positioned between the rows of bubbles in the lattice are confining means which define the lattice translation axis. The two conductor circuits are activated sequentially by bi-polar current drivers such as two sinusoidal current sources which are 90.degree. out-of-phase.

Abstract: A method of forming a serrated surface topography useful for the unidirectional propagation of magnetic domains is disclosed. The method includes the step of forming a substantially rectangular wave topograhy on the surface of the structure and subsequently ion milling the rectangular wave topography at an oblique angle of incidence to form the serrated surface topography.