Bell Telephone Laboratories

At&t Bell Laboratories

Western Electric Company, Inc.

American Telephone & Telegraph Co., At&t Bell Laboratories

Andrew H Bobeck

Roman Kowalchuk

Robert Frederick Fischer

Terence J Nelson

Robert Louis Hartman

Peter Istvan Bonyhard

Terry B Prince

James C North

Lloyd R Harriott

George J Przybylek

Daniel R Kaplan

Martin James Stevenson

William J Tabor

Donald Eugene Kish

Bruce Hamilton McGahey

Henry Evelyn Scovil

William Martin Melbert, Jr

Irynej Danylchuk

A reflection filter is disposed on a solid state laser so as to preferentially reflect TE or TM modes and to suppress oscillation within the resonator of the non-reflected modes. In one embodiment, the filter includes a layer having a plurality of grooves which may be straight and parallel or curved to approximate the mode shape. In another embodiment, the filter includes a polarization sensitive film, without grooves, which either absorbs or transmits the undesired mode. Specifically described is a buried heterostructure semiconductor DFB laser with such a reflection filter formed on at least one facet thereof.

Tranverse mode control in solid state lasers

A field-access magnetic bubble memory includes an improved expander-detector arrangement. An optimized element shape provides for a constant magnetic field strength at critical points in the drive field cycle. Improved high bias operation results.

Field access magnetic bubble memory with improved expander-detector

Magnetic devices exemplified by bubble devices depend upon functional magnetic layers initially produced by epitaxy and reduced to effectively thinned surface layers by ion implantation. Implantation is at well-defined energy spectral levels which minimize effect on surface layers and which predominantly affect a 'buried layer'. As a result, such affected layer acts as a boundary layer of a functional layer which is spaced away from an interface between a substrate and a deposited layer. Commercial significance is primarily concerned with high bit density devices in which effectively thinned regions are less than 3 micrometers in thickness.

Magnetic devices and method of manufacture

A new geometry for the propagation elements of a field-access magnetic bubble memory is disclosed which is tolerant of relatively wide gaps between elements and lower drive fields. The elements have shapes which define bubble 'traps' operative to hold bubbles for relatively high efficiency transfers between elements. In alternate embodiments, the elements have an L-shape or a 'pickaxe' shape.

Magnetic bubble memory

A Hall detector for magnetic bubbles is characterized by an apertured detection area designed to detect only the return field of the bubble. A series arrangement of the detectors is designed to mate with a bubble expander for detecting a strip domain for detecting the return field associated with a strip domain.

Magnetic domain memory with Hall effect detector

A conductor-access, magnetic bubble memory organized in the major-minor mode has minor loops separated into minor loop segments. The segments can be powered for moving bubbles selectively only within the corresponding segments of the minor loops. A transfer operation moves bubbles between minor loop segments permitting bubble movement to the major loop. The ability to move bubbles only in a selected set of corresponding segments of the loops at a time permits operation with highly attractive power requirements.

Segmented, conductor access, magnetic bubble memory

Continuous film type, current-access bubble memories are designed for low power operation by including, along the current paths, areas of reduced width. The areas of reduced widths are characterized by relatively high current densities, which are preferred, for example, for expansion detected or operation, without an increase in power consumption.

Conductor access bubble memory arrangement

A conductor access, magnetic bubble memory is organized in a major-minor mode by including transfer locations in the conducting layers which define the normal bubble propagation implementation. An attractive partitioning of each of the two conducting layers permits the minor loops and the major loop to be operated synchronously or independently resulting in short duty cycles which permit low power operation to be achieved.

Conductor access magnetic bubble memory arrangement

An expander-detector arrangement for a conductor-access, magnetic bubble memory is realized by the inclusion in an electrically-conducting layer in which bubble propagation currents are impressed sets of apertures operative to enlarge a bubble laterally. For this purpose increasingly greater numbers of apertures are arranged laterally with respect to the axis of bubble movement through successive stages of the expander-detector arrangement. The actual detector is formed at the stage including the maximum number of apertures.

Magnetic bubble memory with expander-detector arrangement

Magnetic bubble functional elements are implemented by aperture patterns in a single layer of electrically-conducting material. The operations of the elements are compatible with single-level conductor driven bubble memories described in A. H. Bobeck patent applications, Ser. Nos. 857,921 now U.S. Pat. No. 4,143,419 issued Mar. 6, 1979 and 856,925, filed Dec. 6, 1977, and in A. H. Bobeck-F. J. Ciak patent application, Ser. No. 899,578, filed Apr. 24, 1978 now abandoned.

Magnetic bubble memory with single-level bubble functional elements

A high speed magnetic bubble memory is realized with two like-apertured metallic layers each adapted for substantially uniform overall current flow. The apertures locally modify the current flow to provide localized field gradients for moving bubbles in an adjacent bubble layer. The patterns of apertures in the two layers are offset with respect to one another and the layers are pulsed in sequence in a manner to move bubbles along propagation paths defined by the patterns of apertures.

A conductor-access, magnetic bubble memory is realized with a single metallization level for propagation. The familiar undulating or serpentine conductor pattern used for moving bubbles is modified to allow a simple and easily realizable, low power drive arrangement where currents flow parallel to the bubble paths.

Conductor-access, magnetic bubble memory

A conductor-access magnetic bubble memory is realized with a single electrically-conductive film for the propagation of bubbles. The film is characterized by sequences of apertures in the film. The sequences define paths for bubble movement in response to controlled current pulses. Ion-implanted regions offset with respect to the aperture edges ensure unidirectional bubble movement along the paths.

Magnetic bubble memory with single level electrically-conducting, drive

A low power, conductor-access, bubble memory is realized with a single level of metallization for providing the requisite propagation fields. Sets of apertures in the conducting layer define bubble paths, and permalloy elements aligned with the apertures overlie the conducting layer at end portions and contact the exposed bubble layer at midportions. Current flow is established transverse to the bubble paths.

A magnetic bubble memory with a single electrically-conducting layer for defining a bubble propagate arrangement is adapted to provide a compatible bubble expander detector by a sequence of increasingly larger apertures in the conducting layer.

Growing community of inventors

Chatham, NJ, United States of America

Andrew H Bobeck