Abstract: A network device of an optical network terminal (ONT) includes an optical communication interface, an input interface, a memory and a processor. Wherein the optical communication interface transmits optical signals with adjusted transmission power; the input interface is used to input a distance; the memory stores a plurality of distances, and a plurality of databases respectively correspond to the distances; the processor electrically connects to the optical communication interface, input interface and the memory, and is used to access the database in the memory corresponding to the inputted distance, and then adjust the transmission power of the optical communication interface according to the content in the database. In addition, a method of adjusting the power of optical signals is further provided in this invention.

Abstract: A data storage device is disclosed comprising a disk surface comprising a plurality of tracks, wherein each track comprises a plurality of data sectors and a plurality of servo sectors. The data storage device further comprises a head actuated over the disk surface, the head comprising at least one read element and at least one write element. Control circuitry is configured to use the head to write to a first data sector on the disk surface while simultaneously reading from a first servo sector on the disk surface.

Abstract: An optical information recording medium reproducing apparatus 1 includes: a signal detecting/extracting section 15 extracting, from reproduction signal data, extracted reproduction signal data corresponding to a predetermined data pattern; a calculating circuit 10 calculating, from the extracted reproduction signal data, a reproducing power control value for controlling laser light reproducing power; and a reproducing power control section 16 controlling the reproducing power based on the reproducing power control value. The predetermined data pattern is obtained from a space which is sandwiched between marks of ?/2NA or longer and is shorter than ?/4NA and/or a mark which is sandwiched between spaces of ?/2NA or longer and is shorter than ?/4NA.

Abstract: A ferroelectric recording medium includes a ferroelectric recording layer on an electrode layer, which includes an insulative layer on the ferroelectric recording layer, and includes non-continuous electrically conductive coating portions on the insulative layer.

Abstract: The optical storage medium comprises a substrate layer, a data layer having a pit/land data structure with data arranged in tracks on the substrate layer, and a nonlinear layer with a super-resolution structure disposed on the data layer, wherein a land having a size below the diffraction limit is inverted to a pit and enclosed by auxiliary lands, and a pit having a size below the diffraction limit is inverted to a land and enclosed by auxiliary pits. The optical storage medium is in particular a read-only optical disc comprising a phase-change material, for example AgInSbTe, for providing the super-resolution effect.

Abstract: In an information recording/reproducing method performing a thermo-magnetic recording, a tracking offset value of a recording light spot and/or a tracking offset value of a magnetic flux detecting element is changed in accordance with a radial position at which a tracking is performed at the present time, to make a direction of a magnetic wall of a recording magnetic domain in accord with a longitudinal direction of the magnetic flux detecting element. Alternatively, a shape of a heated area is changed to be in accord with the direction of the magnetic flux detecting means at respective radial position, to make the direction of the magnetic wall of the recording magnetic domain in accord with the longitudinal direction of the magnetic flux detecting element.

Abstract: In an information recording/reproducing method performing a thermo-magnetic recording, a tracking offset value of a recording light spot and/or a tracking offset value of a magnetic flux detecting element is changed in accordance with a radial position at which a tracking is performed at the present time, to make a direction of a magnetic wall of a recording magnetic domain in accord with a longitudinal direction of the magnetic flux detecting element. Alternatively, a shape of a heated area is changed to be in accord with the direction of the magnetic flux detecting means at respective radial position, to make the direction of the magnetic wall of the recording magnetic domain in accord with the longitudinal direction of the magnetic flux detecting element.

Abstract: A thermally assisted magnetic recording medium includes a substrate having a first surface and a second surface opposite to the first surface. A recording layer is formed on the first surface of the substrate. A plurality of thermally conductive regions are provided at the first surface of the substrate to extend in parallel to each other and about the center of rotation of the recording medium. The thermally conductive regions have a higher thermal conductivity than the substrate, and are at least partially embedded in the substrate.

Abstract: A domain wall displacement detection (DWDD) system magneto-optical recording medium forms a land 3 and a groove 4 as signal recording areas. When a domain wall displacement improvement is changed by irradiating annealing light La on a boundary wall surface 5 between the land 3 and the groove 4, the position of this annealing light is detected by an annealing light scanning position displacement detecting wobbling portion 7 formed at a portion extending along the recording track length direction of the boundary wall surface 5. The annealing light scans this wobbling portion 7, whereby a vibration amplitude of a cycle corresponding to the cycle of the wobbling portion 7 is produced to thereby detect and monitor the miniscule change of the scanning position of the annealing light with high sensitivity. Thus, in the DWDD system magneto-optical recording medium, the scanning position of the annealing light at the boundary wall surface between the land 3 and the groove 4 can be detected with high sensitivity.

Abstract: A record mark is formed on a master disc DS. The record mark is formed substantially along a spiral standard locus, but a record mark position is displaced in a direction crossing the spiral standard locus according to record data. A wobble is formed such that the average value of the displacement of the record mark position is zero for each predetermined data unit with the standard locus as a reference.

Abstract: An optical disk recording method of recording data on an optical disk by applying laser light to a track of the optical disk, includes the steps of a) driving a plurality of laser light sources in sequence in a time division manner, and applying a light flux to one track of the optical disk successively, and b) producing a plurality of rows of record marks in the one track.

Abstract: The present invention is a method of reading and writing in MAMMOS that uses the edge of the thermal profile for detection of a domain rather than using the tip of the profile. By using the edge, it is possible to detect the position of domains rather than merely the presence of domains. Thus, domain positions are used to store data. By measuring these positions relative to the last domain, more accuracy can be gained. The new scheme is called Domain Position Detection for MAMMOS (DPD-MAMMOS). In DPD-MAMMOS, the information is encoded into the MAMMOS media in the form of the position of the domains rather than the presence of the domains. In this way, each domain stored in the media can contain several bits or possibly bytes of information. Methods of reading and writing information are disclosed.

Abstract: A magneto-optical recording medium includes a substrate and a reproducing layer and a recording layer provided on the substrate. A recording magnetic domain is provided in the recording layer by heating the recording layer by irradiation with light and applying a recording magnetic field to the recording layer in such a manner that information is recorded in the recording layer. The recording layer is a magnetic film having magnetic anisotropy in a direction perpendicular to the film surface, and the magnetic film holds the recording magnetic domain formed therein. The magneto-optical recording medium further comprises a intermediate layer and a reproducing aid layer between the reproducing layer and the recording layer. Saturated magnetization of the reproducing aid layer increases with an increase in the temperature of the reproducing aid layer.

Abstract: A re-recordable data storage medium is disclosed. One embodiment of the medium includes a dielectric material and a filler material. The dielectric material is organized in columnar channels over which memory cells are logically distributed. The filler material is within the columnar channels to realize the memory cells. The filler material of each memory cell has at least a first configuration and a second configuration. The first configuration corresponds to a first storable logical value, and the second configuration corresponds to a second storable logical value.

Abstract: A magneto optical recording medium capable of stable recording and readout using a DWDD system is provided. The magneto optical recording medium of the present invention comprises an optical disk substrate and a multilayer recording film comprising essentially a readout layer, an intermediate layer, and a recording layer successively formed on top of the substrate. The readout layer has a smaller magnetic domain wall coercivity than the recording layer. The intermediate layer comprises a magnetic layer whose Curie temperature is lower than the readout layer and the recording layer. A recorded/readout magnetic domain corresponding to recorded/readout information is formed only in a groove area of the optical disk substrate. The thickness of the recording film at the boundary between mutually adjacent recording track areas is smaller than the thickness of the recording film in the center portions of the recording track areas.

Abstract: The present invention provides a method of recording information on a magneto-optical recording medium of domain wall displacement type having a preformat area and a data area succeeding thereto, comprising the steps of generating a reproduction signal from said medium by utilizing a light beam, detecting a reference position based on said reproduction signal, determining, based on a result of the detection, a recording start timing at which a formation of a recording magnetic domain is started at a distance at least not shorter than a displacement amount of a domain wall away from a start position of said data area; and starting a recording with said determined recording start timing.

Abstract: An optical information-recording medium having in-groove pits, which is excellent in recording and reproduction characteristics and tracking characteristics, is provided. A method for producing the optical information-recording medium is also provided. Further, a stamper to be used for producing a substrate for the optical information-recording medium and a method for producing the same are also provided. In the optical information-recording medium of the present invention, the in-groove pits, which have flat bottom surfaces, are arranged on a groove which has a flat bottom surface.

Abstract: An information recording medium for reproducing information by irradiation with a laser beam condensed by an objective lens with a numerical aperture NA includes a disk-shaped substrate and a recording layer disposed on the substrate. On the surface of the substrate, a plurality of prepit regions and a plurality of data regions are disposed alternately along spiral or concentric virtual track centers. Each prepit region includes a pair of wobble pits for tracking servo, and a length L (?m) of the wobble pit along the virtual track center, a wavelength ? (?m) of the laser beam, and a numerical aperture NA satisfy a relationship: 0.3?L. NA/??0.65.

Abstract: A magnetic recording medium comprises an information-recording film and a ferromagnetic film on a substrate. The information-recording film is composed of, for example, an amorphous ferrimagnetic material having perpendicular magnetization. Further, the ferromagnetic film is composed of a magnetic material which has saturation magnetization larger than that of the information-recording film. Accordingly, the leak magnetic flux from the ferromagnetic film is larger than that from the information-recording film. The magnetic recording medium and a magnetic recording apparatus are obtained, which are excellent in thermal stability and which are preferred to perform super high density recording.

Abstract: An optical reproducing device according to the present invention detects mean amplitude values of short marks and long marks, which are recorded marks for reproducing power control, by means of a short mark level detecting circuit and a long mark level detecting circuit. Then a differential amplifier compares a ratio between these two mean amplitude values with a standard value, and outputs the result of this comparison. Thereafter, a reproducing power control circuit controls reproducing power of a semiconductor laser such that the absolute value of this comparison result is reduced. Since mean values of the amplitude values of the short marks and long marks are detected, the detection results are very accurate, and the precision of control of reproducing power can be greatly improved.

Abstract: An optical disk recording method of recording data on an optical disk by applying laser light to a track of the optical disk, includes the steps of a) driving a plurality of laser light sources in sequence in a time division manner, and applying a light flux to one track of the optical disk successively, and b) producing a plurality of rows of record marks in the one track.

Abstract: A device scans an optical record carrier having optically detectable marks along a track. The device includes a radiation source for emitting a radiation beam, an objective system for guiding the radiation beam to the record carrier, and a radiation-sensitive detection system for receiving radiation from the record carrier. The detection system includes at least two detectors on both sides of a dividing line. Each detector has an output for providing a detector signal. An electronic circuit forms a focus error signal from the detector signals. The electronic circuit determines a time or phase difference between corresponding parts of the detector signals relating to passage of the radiation beam over patterns of the marks having a spatial frequency in a first range and in a different, second range, and forms a focus error signal in dependence on the time or phase difference.

Abstract: A magneto-optical recording medium, a method for recording and reproducing data using the medium and a magneto-optical recording apparatus are provided in which an optical head reads the recorded data while applying a magnetic field, and the ill effect of the leakage magnetic field from the neighboring tracks can be suppressed so as to obtain a correctly read signal. The magneto-optical recording medium includes a recording layer, an intermediate layer and a reproduction layer. The signal recorded in the recording layer is read using a light beam irradiated externally and a magnetic field applied externally. The signal recorded in the recording layer is transferred to the reproduction layer via the intermediate layer. Marks are recorded so that each of leading and trailing edges of a recorded mark is substantially aligned with center portions of a recorded mark or a space of neighboring tracks, and the neighboring tracks have different polarities.

Abstract: A magneto-optical disk recording and reproducing device, which carries out recording and reproducing for a magnetic super-resolution magneto-optical disk including a recording layer and reproducing layer, has a recording data processing circuit which records long recording marks at different positions between adjacent tracks in a radius direction, each of the long recording marks being larger in diameter than an aperture formed on the reproducing layer by projecting thereon the light beam. According to this arrangement, it is possible to continuously reproduce a data recording area with high accuracy and optimum reproducing power without being affected by adjacent tracks.

Abstract: A magneto-optical recording medium includes a recording layer and a reproducing layer respectively formed by magnetic layers on a substrate. A record magnetic domain is formed within the recording layer by using a magnetic head, which is transferred into a reproducing layer by irradiating a laser beam upon reproduction. The physical length in recording a unit bit is taken as a unit domain length. Where the unit domain length is 1T and “1” is recorded in 1T, “1” is recorded in a former half 1T/2 and “0” is in a latter half 1T/2 by applying one period of an alternating magnetic field to the unit domain length.

Abstract: A magneto-optical recording medium includes a magnetic reproducing layer having an axis of easy magnetization in a direction perpendicular to its layer surface, a magnetic intermediate layer formed on the magnetic reproducing layer and having an axis of easy magnetization in a plane at a room temperature, and a magnetic recording layer formed on the magnetic intermediate layer and having an axis of easy magnetization in a direction perpendicular to its layer surface. The magnetic reproducing layer has a composition of GdxFeCoy where 22 at %≦x≦25 at % and 16 at %≦y≦23 at %.

Abstract: To provide an information recording method, an information recording apparatus and an information reproducing method and an apparatus for a domain wall mobile type magneto-optical medium. In the information recording method, a light beam scans on the medium for heating and at the same time a magnetic field modulated corresponding to the information is applied to a heated point, and a recording magnetic domain having an arc shaped magnetic domain wall bending convex in a forward direction of an operation of the light beam is formed so that the information is recorded. The information recording apparatus, includes an optical head to radiate the light beam for executing the information, a magnetic head to generate a magnetic field modulated corresponding to the information, and a unit for causing the optical head, the magnetic head and the medium to relatively move.

Abstract: An optical disk recording method of recording data on an optical disk by applying laser light to a track of the optical disk, includes the steps of a) driving a plurality of laser light sources in sequence in a time division manner, and applying a light flux to one track of the optical disk successively, and b) producing a plurality of rows of record marks in the one track.

Abstract: A recording method for recording information on a recording layer of a magneto optical recording medium by radiating a recording light beam onto the medium while applying a magnetic field in a recording direction to the medium. The method includes applying a magnetic field having a magnetic field strength H1 in the recording direction when recording a record mark having a mark length A on the recording layer, and applying a magnetic field have a magnetic field strength H2 in the recording direction when recording a record mark having a mark length B (B≠A) on the recording layer. Independent of the lengths of the magnetic domains recorded on the recording layer, the record information can be transferred to a reproducing layer making it possible to reproduce high density record information.

Abstract: A magnetically induced super-resolution (MSR) magneto-optical recording medium capable of reproducing a recorded mark smaller in size than a beam spot, having recording tracks consisting of lands and grooves. This magneto-optical recording medium includes a transparent substrate on which the lands and the grooves are alternately formed, a magnetic reproducing layer formed on the transparent substrate, and a magnetic recording layer formed on the magnetic reproducing layer. Each land has a first width, and each groove has a second width larger than the first width. The depth of each groove on the substrate is 60 nm or less, and the track pitch is 0.7 &mgr;m or less.

Abstract: When recording marks having various lengths are recorded to represent information on a magneto-optical recording medium, a mark length-correcting circuit is used to correct a mark length nT with a mark length correction amount Lc determined for each mark length so that the recording is performed with a shorter mark length nT′=nT−Lc. When reproduction is performed on the magneto-optical recording medium, an appropriate reproducing light power and an appropriate reproducing magnetic field intensity can be easily selected for any recording mark having any length. Thus, the reproducing power margin is widened. The recording method is effective on a magneto-optical recording medium of the MAMMOS type comprising a recording layer and a reproducing layer, in which the light and the magnetic field are applied during the reproduction to transfer a magnetic domain from the recording layer to the reproducing layer in a magnified form.

Abstract: A magneto-optical recording medium includes a substrate and a reproducing layer and a recording layer provided on the substrate. A recording magnetic domain is provided in the recording layer by heating the recording layer by irradiation with light and applying a recording magnetic field to the recording layer in such a manner that information is recorded in the recording layer. The recording layer is a magnetic film having magnetic anisotropy in a direction perpendicular to the film surface, and the magnetic film holds the recording magnetic domain formed therein. The magneto-optical recording medium further comprises a intermediate layer and a reproducing aid layer between the reproducing layer and the recording layer. Saturated magnetization of the reproducing aid layer increases with an increase in the temperature of the reproducing aid layer.

Abstract: By irradiating a light beam between recording tracks of the magneto-optical recording medium, the magnetic anisotropy of at least one layer selected from the group consisting of the domain wall displacement layer and the recording layer formed between the recording tracks can be made lower than that of said layers on the recording tracks, and a bias magnetic field is applied at least between recording tracks while a light beam is radiated. Because of this, initialization of a medium may be conducted simultaneously.

Abstract: A bit of binary information which is one of the “1” and “0” is assigned to a domain pattern which is a combination of a recorded magnetic domain and a magnetic domain magnetized in the direction opposite to the direction in which the recording domain is magnetized. A bit of binary information which is the other of “1” and “0” is assigned to a domain pattern consisting of two magnetic domains magnetized in the same direction as the foregoing magnetic domain is magnetized. Consequently, two or more consecutive bits of record information are formed, on a recording layer, as a series of domain patterns each of which is a combination, as a record information unit, of a recorded magnetic domain and a magnetic domain magnetized in the direction opposite to the direction in which the recording domain is magnetized. Independent of the lengths of the magnetic domains recorded on the recording layer, the record information can be transferred to a reproducing layer.

Abstract: A bit of binary information which is one of “1” and “0” is assigned to a domain pattern which is a combination of a recorded magnetic domain and a magnetic domain magnetized in the direction opposite to the direction in which the recording domain is magnetized. A bit of binary information which is the other of “1” and “0” is assigned to a domain pattern consisting of two magnetic domains magnetized in the same direction as the foregoing magnetic domain is magnetized. Consequently, two or more consecutive bits of record information are formed, on a recording layer, as a series of domain patterns each of which is a combination, as a record information unit, of a recorded magnetic domain and a magnetic domain magnetized in the direction opposite to the direction in which the recording domain is magnetized. Independent of the lengths of the magnetic domains recorded on the recording layer, the record information can be transferred to a reproducing layer.

Abstract: A signal reproducing method for reproducing information by domain wall displacement on a recording medium having recorded information comprises steps of projecting a light spot onto the recording medium to cause temperature distribution thereon, moving relatively the light spot and the recording medium, applying a reproducing magnetic field to the light spot area on the recording medium to prevent displacement of the domain wall from the rear portion of the moving light spot into the inside thereof, and detecting the domain wall displacement to reproduce the information. The temperature gradient may satisfy the relation below: |G1|>|G2| where G1 is the temperature gradient in the front portion in the moving direction, and G2 is the temperature gradient in the rear portion in the moving direction.