Man M Cheung

US Patent:

6912235, Jun 28, 2005

Filed:

Jul 31, 2002

Appl. No.:

10/210039

Inventors:

Douglas W. Anthon - El Cerrito CA, US
Jill D. Berger - Los Gatos CA, US
Alexander A. Tselikov - Fremont CA, US
Stephen J. Hrinya - San Jose CA, US
Howard S. Lee - San Jose CA, US
Alan A. Fennema - San Jose CA, US
Man F. Cheung - Campbell CA, US

Assignee:

Iolon, Inc. - San Jose CA

International Classification:

H01S003/098
H01S003/13

US Classification:

372 2902, 372 18, 372 19, 372 32

Abstract:

An apparatus and method for controlling the phase of a tunable laser is provided. Stabilization of the mode of a laser beam is provided as the laser is tuned to a target frequency. For one embodiment, a laser generates a reference beam and an output beam. The power of each of beam is measured by optical detectors, and a ratio thereof is utilized to detect when a mode hop occurs as the laser is coarsely tuned. The average of the pre and post mode hop ratios is utilized as a control setpoint while finely tuning the laser to the target frequency. Wavelength lockers, optical power dividers and optical detectors are utilized to determine power levels of the reference and output beams while also monitoring frequency characteristics thereof. A control unit utilizes the outputs from the wavelength locker to control the operation of the extended cavity laser during and after tuning.

US Patent:

7773335, Aug 10, 2010

Filed:

Aug 15, 2008

Appl. No.:

12/192981

Inventors:

Jason Adler - Fremont CA, US
David Rutherford - San Jose CA, US
Man Cheung - Campbell CA, US
Perry Neos - Los Altos CA, US
Luan Ton-That - San Jose CA, US

Assignee:

Marvell International Ltd. - Hamilton

International Classification:

G11B 21/02
G11B 5/596
G11B 5/09

US Classification:

360 75, 360 51, 360 7707

Abstract:

Methods, systems, and apparatus, including computer program products, are described for calibrating servos, and in some implementations for calibrating spiral servos for use in self-servo-write processes. In one aspect, a method is provided that includes determining a measured slope of a spiral, and calibrating radial spacing between servo tracks using the measured slope and a target slope.

US Patent:

8094405, Jan 10, 2012

Filed:

Oct 24, 2008

Appl. No.:

12/258351

Inventors:

Edward Ying - Berkeley CA, US
Pantas Sutardja - Los Gatos CA, US
Man Cheung - Campbell CA, US

Assignee:

Marvell International Ltd. - Hamilton

International Classification:

G11B 5/596

US Classification:

360 7704

Abstract:

Methods, systems and computer program products for compensating repeatable run-out (RRO) are described. In some implementations, RRO may be compensated by predicting the RRO and subsequently subtracting the predicted RRO from the actual value of the RRO to cancel out the undesired effect caused by the RRO during operation. More specifically, RRO generated at each spindle motor rotation may be predicted by measuring the position errors associated with the RRO with respect to a current position of a read/write head. A computational model then may be utilized to determine one or more correction factors to compensate for the RRO.

US Patent:

8194343, Jun 5, 2012

Filed:

Jul 16, 2010

Appl. No.:

12/838016

Inventors:

Jason Adler - Fremont CA, US
David Rutherford - San Jose CA, US
Man Cheung - Campbell CA, US
Perry Neos - Los Altos CA, US
Luan Ton-That - San Jose CA, US

Assignee:

Marvell International Ltd. - Hamilton

International Classification:

G11B 21/02
G11B 5/596
G11B 5/09

US Classification:

360 75, 360 51, 360 7707

Abstract:

Systems, methods, and apparatuses, including computer program products, are described for, in at least one implementation, determining a measured slope of a spiral, calibrating radial spacing between servo tracks according to a relationship between a target slope and the measured slope, wherein an amount of calibration for the radial spacing varies directly with the relationship between the target slope and the measured slope, and generating servo tracks according to the calibrated radial spacing.