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公开(公告)号：US11961543B2
公开(公告)日：2024-04-16
申请号：US17898936
申请日：2022-08-30
发明人： Karim Tatah , Mourad Benakli , James Gary Wessel
IPC分类号： H01S5/06 , G11B5/02 , G11B5/09 , G11B5/40 , G11B5/455 , G11B7/1263 , H01S5/024 , H01S5/026 , H01S5/065 , H01S5/068 , G11B5/00 , H01S5/062
CPC分类号： G11B7/1263 , G11B5/02 , G11B5/09 , G11B5/40 , G11B5/455 , H01S5/0261 , H01S5/0612 , H01S5/0651 , H01S5/06804 , H01S5/06808 , G11B2005/0021 , H01S5/02453 , H01S5/0617 , H01S5/06216
摘要： A method and apparatus provide for determining a temperature at a junction of a laser diode when the laser diode is operated in a lasing state that facilitates heat-assisted magnetic recording, comparing the junction temperature and an injection current supplied during the lasing state to stored combinations of junction temperature and injection current, and determining a likelihood of mode hopping occurring for the laser diode during the lasing state based on the comparison to stored combinations of junction temperature and injection current.
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公开(公告)号：US10832704B2
公开(公告)日：2020-11-10
申请号：US16716836
申请日：2019-12-17
发明人： Drew Michael Mader
IPC分类号： G11B11/105 , G11B5/012 , G11B13/04 , G11B5/00 , G11B7/1267 , G11B7/1263 , G11B7/126
摘要： A method includes generating, during manufacture of a heat-assisted magnetic recording (HAMR) disk drive, a temperature compensation equation for a compensation factor using initial operating currents supplied to a laser diode of the disk drive at different initial operating temperatures and an efficiency value based on the initial operating temperatures. The operating currents are representative of currents for recording data to or erasing data from a magnetic recording medium. The temperature compensation equation is stored in the disk drive. A subsequent efficiency value is determined based on at least one of the initial operating temperatures and an operating temperature differing from the initial operating temperatures. An updated compensation factor at the operating temperature is determined during field operation using the temperature compensation equation and the subsequent efficiency value. An updated operating current is calculated using the updated compensation factor and the operating temperature. A current supplied to the laser diode for a subsequent write operation is adjusted to the updated operating current.
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3.发明授权公开(公告)号：US10770106B1
公开(公告)日：2020-09-08
申请号：US16724569
申请日：2019-12-23
IPC分类号： G11B5/02 , G11B7/126 , G11B5/40 , G11B5/012 , G11B5/455 , G11B11/105 , G11B11/00 , G11B5/60 , G11B20/18 , G11B7/1387 , G11B7/1263 , G11B7/1267 , G11B5/00
摘要： A heat-assisted recording head is moved onto a ramp such that the recording head is thermally isolated from a moving disk. A heating device is activated on the recording head to cause the recording head to obtain a high temperature that is not obtainable when proximate to the moving disk. The recording head is moved over the moving disk such that the recording head reaches an operating temperature that is below the high temperature. One or more temperatures between the high temperature and the operational temperature are determined at which a laser of the recording head experiences mode-hopping. The one or more temperatures are stored and accessed by a controller to mitigate mode hopes during an operation of the recording head.
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公开(公告)号：US10692525B2
公开(公告)日：2020-06-23
申请号：US16136389
申请日：2018-09-20
发明人： Aidan Dominic Goggin , Mark Anthony Gubbins , Kelly Elizabeth Callan , Reyad Mehfuz , Marcus B. Mooney , Fadi El Hallak , Paula Frances McElhinney
IPC分类号： G11B7/126 , G11B11/105 , G11B5/48 , G11B5/00 , G11B7/1263 , G11B7/1267 , G11B5/60
摘要： An apparatus includes a substrate. A laser is formed on a non-self supporting structure and bonded to the substrate. A waveguide is deposited proximate the laser. The waveguide is configured to communicate light from the laser to a near-field transducer that directs energy resulting from plasmonic excitation to a recording medium. A light detector is configured to detect an amount of light. At least one laser heater is disposed proximate the laser. A controller is configured to control current supplied to the at least one heater based on the detected amount of light.
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5.发明授权公开(公告)号：US10410668B1
公开(公告)日：2019-09-10
申请号：US16249452
申请日：2019-01-16
IPC分类号： G11B5/00 , G11B7/1263 , G11B5/09 , G11B20/18 , G11B5/012
摘要： A slider configured for heat-assisted magnetic recording includes a laser diode optically coupled to a waveguide of the slider. A power supply is coupled to the laser diode. A preamplifier is coupled to the power supply. The preamplifier is configured to monitor a forward voltage across the laser diode while operating the laser diode at a constant current during a write operation, detect a change in the forward voltage indicative of laser power instability, and generate a signal in response to detecting the forward voltage change.
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公开(公告)号：US10395680B1
公开(公告)日：2019-08-27
申请号：US15956044
申请日：2018-04-18
发明人： James Gary Wessel , Chen Wang
IPC分类号： G11B11/105 , G11B5/48 , G11B7/1263 , G11B5/60 , G11B5/012 , G11B5/40 , G11B5/02 , G11B5/00
摘要： An apparatus includes a slider having an air bearing surface (ABS). A near-field transducer (NFT) is disposed at or near the ABS. The slider has an optical waveguide configured to couple light from a laser source to the NFT. A thermal sensor is disposed at a leading edge of the NFT, the thermal sensor has an ABS section situated at or proximate the ABS and a distal section extending away from the ABS. The thermal sensor is configured to detect changes in output optical power of the laser source and contact between the slider and a magnetic recording medium.
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公开(公告)号：US10366722B1
公开(公告)日：2019-07-30
申请号：US15978432
申请日：2018-05-14
发明人： Riyan Mendonsa , James Dillon Kiely , Joshua Ward Christensen , Jon D. Trantham , Chad Robert Barry , Tim Rausch
IPC分类号： G11B11/00 , G11B7/1263 , G11B5/00 , G11B7/1267 , G11B5/60 , G11B7/126
摘要： An apparatus comprises a laser diode configured to generate modulated light during a write operation in response to receiving modulated current having a mean amplitude that varies or is constant. A slider is configured for heat-assisted magnetic recording and to receive the modulated light. A writer heater of the slider is configured to receive power during the write operation having a magnitude that varies or is constant. A sensor is situated on or within the slider. The sensor is configured to produce a sensor signal representative of output optical power of the laser diode. Measuring circuitry is coupled to the sensor and configured to measure a change in the sensor signal indicative of a laser mode hop during the write operation.
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8.发明授权公开(公告)号：US10255940B1
公开(公告)日：2019-04-09
申请号：US15408982
申请日：2017-01-18
IPC分类号： G11B5/00 , G11B7/1263 , G11B5/09 , G11B20/18 , G11B5/012
摘要： A slider configured for heat-assisted magnetic recording includes a laser diode optically coupled to a waveguide of the slider. A power supply is coupled to the laser diode. A preamplifier is coupled to the power supply. The preamplifier is configured to monitor a forward voltage across the laser diode while operating the laser diode at a constant current during a write operation, detect a change in the forward voltage indicative of laser power instability, and generate a signal in response to detecting the forward voltage change.
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9.发明申请公开(公告)号：US20180114542A1
公开(公告)日：2018-04-26
申请号：US15671262
申请日：2017-08-08
IPC分类号： G11B7/1263 , H01S5/0683 , G11B5/012 , H01S5/042 , G11B5/00
CPC分类号： G11B5/012 , G11B2005/0021 , H01S5/0427 , H01S5/0683
摘要： Before writing to a heat-assisted magnetic recording medium, a DC signal modulated with an AC signal is applied to a laser of a read/write head. A modulation level of an optical power sensor is measured, the optical power sensor being coupled to detect optical output of the laser in response to the modulated current. A target value of the DC signal that causes the modulation levels to reach a predetermined value between zero and a maximum value is determined and used to set a bias current for subsequent activation of the laser based.
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10.发明授权公开(公告)号：US09916868B1
公开(公告)日：2018-03-13
申请号：US15229967
申请日：2016-08-05
发明人： Kangkang Wang , Xiaobin Zhu , Ganping Ju , Kai Chieh Chang , Yingguo Peng , Timothy J. Klemmer , Jan-Ulrich Thiele , Pin-Wei Huang
IPC分类号： G11B27/36 , G11B7/1263 , G11B5/024 , G11B5/09 , G11B7/1267 , G11B5/00
CPC分类号： G11B27/36 , G01R33/0325 , G11B5/024 , G11B5/09 , G11B5/4555 , G11B7/1263 , G11B7/1267 , G11B2005/0021
摘要： An apparatus comprises a spindle to rotate a magnetic recording medium and a magnetic field generator to expose a track of the medium to a DC magnetic field. The magnetic field generator is configured to saturate the track during an erase mode and reverse the DC magnetic field impinging the track during a writing mode. A laser arrangement heats the track during the erase mode and, during the writing mode, heats the track while the track is exposed to the reversed DC magnetic field so as to write a magnetic pattern thereon. A reader reads the magnetic pattern and generates a read signal. A processor is coupled to the reader and configured to determine an anisotropy parameter using the read signal. The apparatus can further comprise a Kerr sensor that generates a Kerr signal using the magnetic pattern.
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