Western Digital (fremont), Inc.

Jds Uniphase Corporation

Read Rite Corporation

Read-rite Corportion

Zi-Wen Dong

Jyoti Kiron Bhardwaj

Hiroaki Yamada

Yingjian Chen

Robert Brainard

David J Dougherty

Sanjay M Thekdi

Anantharaman Vaidyanathan

Thomas Nguyen

David K Nakamoto

Erik W Egan

Niranjan Gopinathan

Yingchao Yan

David John Seagle

James Han Wang

Suresh Ramalingam

Qunwen Leng

Xizeng Shi

Yugang Wang

Zhupei Shi

Douglas E Crafts

Francis H Liu

Matthew R Gibbons

Ronald A Barr

Barthelemy Fondeur

Kenneth E Knapp

Hugh Craig Hiner

Jinxi Shen

Kevin K Lin

William D Jensen

James F Farrell

Kenzo Ishida

Steven M Swain

David J Chapman

Chester Xiaowen Chien

Bill Crue

Lijun Tong

Mark Brian Farrelly

Qing He

Yimin Hua

Ron Barr

Joyce Hsiang

Song Pang

Joyce Thompson

Russel Stearns

Domenico Di Mola

James Wong

An optical device for rearranging wavelength channels in an optical network is disclosed. The optical device has a wavelength selective coupler having one input port and a plurality of output ports coupled to a plurality of input ports of an optical grating demultiplexor such as an arrayed waveguide grating. The wavelength channels in each of the input ports are dispersed by the demultiplexor and are directed to a plurality of output ports of the optical grating demultiplexor. As a result, at least one wavelength channel at each of the input ports of the optical grating demultiplexor is coupled into a common output port. The optical device is useful in passive optical networks wherein a same demultiplexor is used for simultaneous multiplexing and demultiplexing of wavelength channels.

Optical device for rearranging wavelength channels

The present invention provides a write element for use in magnetic data recording system such as a computer disk drive. The write head utilizes the advantageous properties of high magnetic moments while overcoming the corrosion problems engendered by such materials. The write element includes a magnetic yoke constructed of first and second magnetic poles joined to one another at a back gap. While the majority of the poles are constructed of a high magnetic moment material a layer of relatively low magnetic moment material is provided on the first pole at the back gap portion of the first pole. The relatively low magnetic moment material prevents corrosion of the first pole during subsequent manufacturing of the write head. An electrically conductive coil passes through the magnetic yoke and is insulated there from. By passing an electrical current through the electrical coil, a magnetic flux is generated in the yoke. This magnetic flux then generates a magnetic fringing field in at a write gap of the yoke. The fringing field imparts magnetic data onto a recording medium passing thereby.

Inductive write head having high magnetic moment poles and low magnetic moment thin layer in the back gap, and methods for making

A planar lightwave circuit includes at least one optical waveguide core, and at least one feature proximate the core having a stress-engineered property to balance stress and therefore minimize birefringence affecting the core. A protective passivation layer is formed over the core and the feature to be substantially non-interfering with the balanced stress provided by the feature. The stress balancing feature may be an overcladding layer formed over the core, doped to have a coefficient of thermal expansion approximately matched to that of an underlying substrate, to symmetrically distribute stress in an undercladding between the overcladding and the substrate, away from the core. The protective passivation layer is formed to have a coefficient of thermal expansion approximately matched to that of the overcladding. In one exemplary embodiment, the passivation layer is formed from silicon nitride. Related concepts of stress release grooves, and core overetching, are also disclosed.

Waveguide stress engineering and compatible passivation in planar lightwave circuits

A disk drive write head () having a bottom pole (), a first insulation layer () formed on the bottom pole (), a coil () formed on the first insulation layer (), a second insulation layer () formed on the coil (), a write gap layer () formed on the second insulation layer (), and a top pole () formed on the write gap layer (), where the top pole () is substantially flat. A second embodiment () is described which is produced by a damascene process.

Inductive writer with flat top pole and pedestal defined zero throat

Data storage and retrieval apparatus with thin film read head having inset extra gap insulation layer and method of fabrication

An inductive transducer having first and second magnetic pedestals disposed between first and second magnetic pole layers and adjacent to a media-facing surface, the pedestals separated by a submicron, nonmagnetic gap. The first pedestal extends less than the second pedestal from the media-facing surface, defining a short throat height. The second pedestal extends further to provide sufficient area for stitching to the second pole layer. The stitching and the thickness provided by the pedestals allow plural coil layers to be disposed between the pole layers, and the second pedestal, as well as other features, can be defined by high-resolution photolithography. The two coil layers have lower resistance, lower inductance and allow the pole layers to be shorter, improving performance. All or part of either or both of the pedestals may be formed of high magnetic saturation material, further enhancing performance.

Inductive transducer with stitched pole tip and pedestal defining zero throat height

A planar lightwave circuit includes an arrayed waveguide grating (AWG), with input and output waveguides, partially curved array waveguides with respective length differences, and planar waveguide regions for focusing optical energy between the input/output and array waveguides. Optimal waveguide widths and spacing along the planar waveguide region facets are disclosed, which are largely determinative of AWG size and optical performance. Also disclosed are optimal cross-sectional waveguide dimensions (e.g., width and height); modified index of refraction difference between the waveguide core and cladding regions; and optimal array waveguide lengths, path length differences, and free spectral range. These features, especially when combined with advanced fiber attachment, passivation and packaging techniques, result in high-yield, high-performance AWGs (both gaussian and flattop versions).

Compact, low insertion loss, high yield arrayed waveguide grating

A method and system for providing a magnetoresistive sensor for reading data from a recording media is disclosed. The method and system include providing at least one barrier layer and a free layer having at least one edge. The at least one edge of the free layer is adjacent to the at least one barrier layer. The free layer is ferromagnetic and has a low coercivity. The method and system also include providing at least one hard magnetic layer. The at least one hard magnetic layer has a coercivity greater than the free layer coercivity. The at least one barrier layer is disposed between the at least one hard magnetic layer and the free layer. The at least one barrier layer is sufficiently thin to allow tunneling of charge carriers between the at least one hard magnetic layer and the free layer.

Method and system for providing edge-junction TMR utilizing a hard magnet as a pinned layer

In at least one embodiment, the apparatus of the invention is a read sensor comprising a shield, a sensor element, an extra shield between the shield and the sensor element, an extra gap between the shield and the sensor and adjacent the extra shield, and a gap layer between the sensor element and the extra shield. The sensor element is positioned in a sensor layer. With the extra shield adjacent to the sensor element and separated by only the relatively thin gap layer, high areal recording density and excellent instability of the sensor element is obtained. At the same time, by fabricating the extra shield to be not significantly wider than the sensor element, the potential for shorting is minimized by placing both the gap and the thicker extra gap between the sensor lead elements and the shield. In at least one embodiment, the method of the invention is for fabricating a read sensor and comprises depositing an extra gap layer onto a shield, removing a portion of the extra gap layer to form a cavity, depositing an extra shield into the cavity, planarizing the extra gap and the extra shield, depositing a gap layer onto the extra gap and the extra shield, and depositing a sensor element onto the gap layer and adjacent to the extra shield.

Data storage and retrieval apparatus with thin film read head having planarized extra gap and shield layers and method of fabrication thereof

Growing community of inventors

Union City, CA, United States of America

Zi-Wen Dong