Abstract: A reproduction signal evaluation method according to the present invention relates to adjustment of an edge portion between a shortest mark and a shortest space in a data sequence including marks and spaces in combination that is recordable on an information recording medium. In a pattern including a shortest mark and a shortest space adjacent before or after the shortest mark, a shift amount of an edge of the shortest mark is obtained from a differential metric calculated regarding one of a first pattern in which a space adjacent to the shortest mark and not adjacent to the shortest space is longer than the shortest space; and a second pattern in which a mark adjacent to the shortest space and not adjacent to the shortest mark is longer than the shortest mark.

Abstract: A laser driving system and method using a write strategy technique where a write strategy signal is generated based on a set of pulses that include timing information and power level information. The set of pulses originate from a set of transmission signals that embody spaces and marks for both starting and changing the set of pulses.

Abstract: A recording parameter setting device includes a trial recording parameter setting section and a reproduced signal quality judging section. The trial recording parameter setting section sets a trial recording parameter capable of controlling a heat level at least rear edges of recording marks, classified in accordance with recording mark lengths, and grouping a predetermined recording mark length or longer into a same group. The reproduced signal quality judging section judges whether a trial recording carried out in accordance with the trial recording parameter satisfies a predetermined reproduced signal quality. If the signal quality is unsatisfactory, the trial recording parameters of the predetermined recording mark length or longer are regrouped and trial recording is carried out again until the reproduced signal satisfies the predetermined signal quality. Then, the reproduced signal quality judging section sets the trial recording parameter as the recording parameter.

Abstract: According to one embodiment, an optical recording medium is provided in which interlayer crosstalk is low and in which stable and high-quality recording characteristics can be obtained. To this end, an optical recording medium comprises a first recording part which includes a first recording layer and a first light reflecting layer and which is disposed on a side closer to a light receiving surface, and a second recording part which includes a second recording layer and a second light reflecting layer and which is disposed on a side farther from the light receiving surface, the first recording part and the second recording part being stacked, wherein the thickness of the second light reflecting layer is larger than the thickness of the first light reflecting layer.

Abstract: According to one embodiment, a re-recordable write-once optical disc by which recording/reproducing can be properly done with a short-wavelength blue laser is provided. The disc has recording layers on which marks are recorded by the laser power of a modulated short wavelength, with a space formed between the recorded marks. The recording layer of the disc uses an organic dye material by which no physical modification or no physical change substantially occurs in an area of the recorded marks.

Abstract: According to one embodiment, an optical recording medium is provided in which interlayer crosstalk is low and in which stable and high-quality recording characteristics can be obtained. To this end, an optical recording medium comprises a first recording part which includes a first recording layer and a first light reflecting layer and which is disposed on a side closer to a light receiving surface, and a second recording part which includes a second recording layer and a second light reflecting layer and which is disposed on a side farther from the light receiving surface, the first recording part and the second recording part being stacked, wherein the thickness of the second light reflecting layer is larger than the thickness of the first light reflecting layer.

Abstract: According to one embodiment, an optical recording medium is provided in which interlayer crosstalk is low and in which stable and high-quality recording characteristics can be obtained. To this end, an optical recording medium comprises a first recording part which includes a first recording layer and a first light reflecting layer and which is disposed on a side closer to a light receiving surface, and a second recording part which includes a second recording layer and a second light reflecting layer and which is disposed on a side farther from the light receiving surface, the first recording part and the second recording part being stacked, wherein the thickness of the second light reflecting layer is larger than the thickness of the first light reflecting layer.

Abstract: A reproduction signal evaluation method according to the present invention relates to adjustment of an edge portion between a shortest mark and a shortest space in a data sequence including marks and spaces in combination that is recordable on an information recording medium. In a pattern including a shortest mark and a shortest space adjacent before or after the shortest mark, a shift amount of an edge of the shortest mark is obtained from a differential metric calculated regarding one of a first pattern in which a space adjacent to the shortest mark and not adjacent to the shortest space is longer than the shortest space; and a second pattern in which a mark adjacent to the shortest space and not adjacent to the shortest mark is longer than the shortest mark.

Abstract: According to one embodiment, an optical recording medium is provided in which interlayer crosstalk is low and in which stable and high-quality recording characteristics can be obtained. To this end, an optical recording medium comprises a first recording part which includes a first recording layer and a first light reflecting layer and which is disposed on a side closer to a light receiving surface, and a second recording part which includes a second recording layer and a second light reflecting layer and which is disposed on a side farther from the light receiving surface, the first recording part and the second recording part being stacked, wherein the thickness of the second light reflecting layer is larger than the thickness of the first light reflecting layer.

Abstract: According to one embodiment, an optical recording medium is provided in which interlayer crosstalk is low and in which stable and high-quality recording characteristics can be obtained. To this end, an optical recording medium comprises a first recording part which includes a first recording layer and a first light reflecting layer and which is disposed on a side closer to a light receiving surface, and a second recording part which includes a second recording layer and a second light reflecting layer and which is disposed on a side farther from the light receiving surface, the first recording part and the second recording part being stacked, wherein the thickness of the second light reflecting layer is larger than the thickness of the first light reflecting layer.

Abstract: A recording parameter setting device setting parameters of pulse sequences forming recording marks on recording media. The device includes a storage section storing first and second look-up tables, and a recording parameter setting section for obtaining from the tables and setting parameters corresponding to recording information. The pulse sequences form at least marks equal to or longer than a first predetermined length but not longer than a maximum mark length, and include top and last sections. Also, the first lookup table stores parameters for top sections that control heat of front edges of marks classified into a same group. The second lookup table stores parameters for last sections for controlling heat of rear edges that are equal to or longer than a second predetermined recording mark length, that is longer than the first predetermined recording mark length, through the maximum recording mark length and classified into a same group.

Abstract: According to one embodiment, an optical recording medium is provided in which interlayer crosstalk is low and in which stable and high-quality recording characteristics can be obtained. To this end, an optical recording medium comprises a first recording part which includes a first recording layer and a first light reflecting layer and which is disposed on a side closer to a light receiving surface, and a second recording part which includes a second recording layer and a second light reflecting layer and which is disposed on a side farther from the light receiving surface, the first recording part and the second recording part being stacked, wherein the thickness of the second light reflecting layer is larger than the thickness of the first light reflecting layer.

Abstract: According to one embodiment, an optical recording medium is provided in which interlayer crosstalk is low and in which stable and high-quality recording characteristics can be obtained. To this end, an optical recording medium comprises a first recording part which includes a first recording layer and a first light reflecting layer and which is disposed on a side closer to a light receiving surface, and a second recording part which includes a second recording layer and a second light reflecting layer and which is disposed on a side farther from the light receiving surface, the first recording part and the second recording part being stacked, wherein the thickness of the second light reflecting layer is larger than the thickness of the first light reflecting layer.

Abstract: Provided herein are hybrid laser diode drivers (LDDs) that drive a laser diode in response to receiving enable signals from a controller. In accordance with specific embodiments, a hybrid LDD includes a read channel to selectively output a read current, one or more write channel each to selectively output a write current, and an oscillator channel to selectively output an oscillator current. Additionally, in specific embodiments the hybrid LDD includes a state machine that receives the enable signals from the controller, and based on the enable signals, controls timing of the currents output by the read, write and oscillator channels.

Abstract: A recording/reproducing device includes a laser and a laser drive carried by a pickup having a drive for movement. A control controls the drives to irradiate the recording medium with laser pulse sequences forming recording marks having recording mark lengths between a predetermined and maximum lengths, a top section, a last section including a cooling period, and an intermediate period. Heat of mark front edges is controlled by recording parameters for top sections that are classified according to recording mark lengths and recording parameters of the first through the maximum recording mark lengths are classified into a same group. Heat of mark rear edges is controlled by cooling start positions for cooling periods classified according to recording mark lengths. Cooling start positions for a second predetermined mark length through the maximum mark length are classified into a same group. The second mark length is longer than the first mark length.

Abstract: A writing current circuit (42) supplies a controlled electrical current to a laser diode (34) for recording data swiftly onto a DVD (16). A plurality of current sources (62) in the writing current circuit (42) supply electrical current directly to the laser diode (34). Each current source (62) respectively receives a single output signal from a current control register (52) included in the writing current circuit (42) which activates or deactivates the current source (62) for supplying a particular quantity of current to the laser diode (34). In one aspect, a pair of current reference signals received by the current source (62) control electrical current supply to the diode (34). Incorporated into these controlling reference signals is a simulation of electrical characteristics of the diode (34). In another aspect, each current source (62) responds to a logical inverse of the output signal from the current control register (52) for controlling overshoot in voltage applied across the diode (34).

Abstract: According to one embodiment, an optical recording medium is provided in which interlayer crosstalk is low and in which stable and high-quality recording characteristics can be obtained. To this end, an optical recording medium comprises a first recording part which includes a first recording layer and a first light reflecting layer and which is disposed on a side closer to a light receiving surface, and a second recording part which includes a second recording layer and a second light reflecting layer and which is disposed on a side farther from the light receiving surface, the first recording part and the second recording part being stacked, wherein the thickness of the second light reflecting layer is larger than the thickness of the first light reflecting layer.

Abstract: According to one embodiment, an optical recording medium is provided in which interlayer crosstalk is low and in which stable and high-quality recording characteristics can be obtained. To this end, an optical recording medium comprises a first recording part which includes a first recording layer and a first light reflecting layer and which is disposed on a side closer to a light receiving surface, and a second recording part which includes a second recording layer and a second light reflecting layer and which is disposed on a side farther from the light receiving surface, the first recording part and the second recording part being stacked, wherein the thickness of the second light reflecting layer is larger than the thickness of the first light reflecting layer.

Abstract: An evaluation method and print wire method which includes (a) fitting a modulation characteristic formula M,m=Msat (1?(Pws?Pasy)/(Pw,m?Pasy)) having a saturated modulation Msat, write start power Pws, and asymptotic power Pasy as parameters to a relation between a plurality of kinds of write power Pw,m and a modulation M,m which is obtained from a signal amplitude of a trial-written signal, and finding an index value of an error which occurs in the fitting step; and (b) evaluating whether or not the relation between the write power and the modulation is valid for write power adjustment by using the index value of the error and a predetermined value the print write method further including (c) setting the write power based upon the result of evaluating and executing a write power process with the set write power.

Abstract: According to one embodiment, an optical recording medium is provided in which interlayer crosstalk is low and in which stable and high-quality recording characteristics can be obtained. To this end, an optical recording medium comprises a first recording part which includes a first recording layer and a first light reflecting layer and which is disposed on a side closer to a light receiving surface, and a second recording part which includes a second recording layer and a second light reflecting layer and which is disposed on a side farther from the light receiving surface, the first recording part and the second recording part being stacked, wherein the thickness of the second light reflecting layer is larger than the thickness of the first light reflecting layer.

Abstract: Aspects of the disclosure can provide a method to optimize optical recording. The method can include recording a pre-defined pattern on an optical medium according to a first write strategy, measuring edge timings corresponding to the pre-defined pattern recorded on the optical medium, determining a second write strategy including at least timing modifications to the first write strategy, and recording data on the optical medium according to the second write strategy. The timing modifications can be determined based on the measured edge timings, edge timing targets for desired edge timings and edge timing sensitivities to the timing modifications.

Abstract: According to one embodiment, an optical recording medium is provided in which interlayer crosstalk is low and in which stable and high-quality recording characteristics can be obtained. To this end, an optical recording medium comprises a first recording part which includes a first recording layer and a first light reflecting layer and which is disposed on a side closer to a light receiving surface, and a second recording part which includes a second recording layer and a second light reflecting layer and which is disposed on a side farther from the light receiving surface, the first recording part and the second recording part being stacked, wherein the thickness of the second light reflecting layer is larger than the thickness of the first light reflecting layer.

Abstract: Aspects of the disclosure can provide a method to optimize optical recording. The method can include recording a pre-defined pattern on an optical medium according to a first write strategy, measuring edge timings corresponding to the pre-defined pattern recorded on the optical medium, determining a second write strategy including at least timing modifications to the first write strategy. The timing modifications can be determined based on means and variances of the measured edge timings, edge timing means and variances targets for desired edge timings, and edge timing sensitivities to the timing modifications.

Abstract: According to one embodiment, an optical recording medium is provided in which interlayer crosstalk is low and in which stable and high-quality recording characteristics can be obtained. To this end, an optical recording medium comprises a first recording part which includes a first recording layer and a first light reflecting layer and which is disposed on a side closer to a light receiving surface, and a second recording part which includes a second recording layer and a second light reflecting layer and which is disposed on a side farther from the light receiving surface, the first recording part and the second recording part being stacked, wherein the thickness of the second light reflecting layer is larger than the thickness of the first light reflecting layer.

Abstract: A recording parameter setting device setting parameters of pulse sequences forming recording marks on recording media. The device includes a storage section storing first and second look-up tables, and a recording parameter setting section for obtaining from the tables and setting parameters corresponding to recording information. The pulse sequences form at least marks equal to or longer than a first predetermined length but not longer than a maximum mark length, and include top and last sections. Also, the first lookup table stores parameters for top sections that control heat of front edges of marks classified into a same group. The second lookup table stores parameters for last sections for controlling heat of rear edges that are equal to or longer than a second predetermined recording mark length, that is longer than the first predetermined recording mark length, through the maximum recording mark length and classified into a same group.

Abstract: According to one embodiment, an optical recording medium is provided in which interlayer crosstalk is low and in which stable and high-quality recording characteristics can be obtained. To this end, an optical recording medium comprises a first recording part which includes a first recording layer and a first light reflecting layer and which is disposed on a side closer to a light receiving surface, and a second recording part which includes a second recording layer and a second light reflecting layer and which is disposed on a side farther from the light receiving surface, the first recording part and the second recording part being stacked, wherein the thickness of the second light reflecting layer is larger than the thickness of the first light reflecting layer.

Abstract: An optical recording method for recording information by irradiating an optical disc medium with a modulated write pulse train of laser light variable over a plurality of power levels such that a plurality of marks are formed on the optical disc medium, edge positions of each of the marks and a space between adjacent two of the marks being utilized for recording of the information.

Abstract: According to one embodiment, an optical recording medium is provided in which interlayer crosstalk is low and in which stable and high-quality recording characteristics can be obtained. To this end, an optical recording medium comprises a first recording part which includes a first recording layer and a first light reflecting layer and which is disposed on a side closer to a light receiving surface, and a second recording part which includes a second recording layer and a second light reflecting layer and which is disposed on a side farther from the light receiving surface, the first recording part and the second recording part being stacked, wherein the thickness of the second light reflecting layer is larger than the thickness of the first light reflecting layer.

Abstract: The invention prevents mark distortion during high-speed recording on an optical disc, thereby improving recording performance. A write pulse signal includes mark periods during which marks 201 are formed and space periods during which no marks are formed. Particular mark periods include a top pulse 101 having first write power Pw; a bias pulse 102 that follows the top pulse 101 and has bias power Pm lower than the first write power Pw; and a last pulse 103 that follows the bias pulse 102 and has second write power Pl lower than the first write power Pw.

Abstract: Pulses modulated between the erase power and the bottom power are used instead of cooling pulses for an optical disk medium that needs a write strategy with 4-valued power levels. Consequently, pulse instruction lines for the cooling pulses, power level instruction lines, and corresponding current source within the laser driver can be omitted. Decrease in size and lower power consumption can be accomplished.

Abstract: A multilayer recording medium has a three-layered structure for an increased capacity, including an L0 layer, an L1 layer, and an L2 layer in order from the side farthest away from the incident surface of laser light. The recording layers are made of respective recording film materials selected so that the recording films of the recording layers have respective recording-reaction temperatures T0, T1, and T2, where T0?T1?T2 and T0<T2. This makes the recording sensitivities of the respective recording layers substantially the same and, by extension, the optimal recording powers of the laser light for the respective recording layers substantially the same so that the recording power of the laser light necessary for recording information on the L0 layer in particular is prevented from becoming excessively high.

Abstract: According to one embodiment, an optical recording medium is provided in which interlayer crosstalk is low and in which stable and high-quality recording characteristics can be obtained. To this end, an optical recording medium comprises a first recording part which includes a first recording layer and a first light reflecting layer and which is disposed on a side closer to a light receiving surface, and a second recording part which includes a second recording layer and a second light reflecting layer and which is disposed on a side farther from the light receiving surface, the first recording part and the second recording part being stacked, wherein the thickness of the second light reflecting layer is larger than the thickness of the first light reflecting layer.

Abstract: According to one embodiment, an optical recording medium is provided in which interlayer crosstalk is low and in which stable and high-quality recording characteristics can be obtained. To this end, an optical recording medium comprises a first recording part which includes a first recording layer and a first light reflecting layer and which is disposed on a side closer to a light receiving surface, and a second recording part which includes a second recording layer and a second light reflecting layer and which is disposed on a side farther from the light receiving surface, the first recording part and the second recording part being stacked, wherein the thickness of the second light reflecting layer is larger than the thickness of the first light reflecting layer.

Abstract: To compensate for edge shifts varying largely in accordance with preceding mark lengths. Provided are a method and a recorder in which a duration of a cooling pulse in each recording pulse string to form a mark having a length of nT is determined on the basis of an edge shift amount of a front edge of a mark whose preceding mark has a length of nT, where n is an integer and T is a channel bit length.

Abstract: A driver comprising: a pattern module configured to generate a plurality of timing parameters in response to a received bit stream; a timing module configured to determine a plurality of multi-bit parameters in response to the timing parameters; and a pulse module configured to (i) generate each of a plurality of pulses in response to a different one of the plurality of multi-bit parameters, (ii) generate each of a plurality of enable signals in response to a variable combination of the plurality of pulses, and (iii) output the plurality of enable signals to a laser driver.

Abstract: An exemplary method for recording a first mark with a first length and a second mark with a second length onto an optical storage medium includes: when recording of the first mark requires a power transition from a first laser power level to a second laser power level, making a specific control signal have a logic transition from a low logic value to a high logic value and other control signals have no logic transition; and when recording of the second mark requires a power transition from a third laser power level to a fourth laser power level, making the specific control signal have the logic transition from the low logic value to the high logic value and other control signals have no logic transition.

Abstract: A recording/reproducing device includes a laser and a laser drive carried by a pickup having a drive for movement and an input for recording information. A control controls the drives to retrieve recording parameters from a predetermined portion of the recording medium, creates pulse sequences using the input recording information and retrieved recording parameters, and forms recording marks having recording mark lengths between a predetermined and maximum lengths, a top section, a last section including a cooling period, and an intermediate period. Heat of mark front edges is controlled by recording parameters for top sections that are classified according to recording mark lengths and recording parameters of the first through the maximum recording mark lengths are classified into a same group. Heat of mark rear edges is controlled by cooling start positions for cooling periods classified according to recording mark lengths.

Abstract: According to a method of the present invention for recording data on an optical disk, a recording pulse corresponding to a long mark includes a combination of a leading pulse and a subsequent intermediate pulse. Further, a level of the leading pulse indicates a first recording power, and a level of the intermediate pulse indicates a second recording power. When an optical disk includes a plurality of recording layers, a ratio of the second recording power to the first recording power is determined for each recording layer. When the recording speed is variable, the ratio of the second recording power to the first recording power is determined for each recording speed.

Abstract: An optical recording medium including a plurality of recording layers to record/reproduce information using light with a predetermined wavelength, the information being recorded on one of the recording layers using a mark and a space, wherein a channel clock period T is provided for recording the mark on one of the recording layers. A plurality of pulses, including a last pulse arranged at an end of the pulses, are used to record the mark with length 3T, the mark being recorded with a condition that a width of the last pulse is minimum 0T and maximum 1.10T, in which a first subsequent level lower than a peak power level of the last pulse is arranged next to the last pulse, and a second subsequent level lower than the peak power level but higher than the first subsequent level is arranged next to the first subsequent level.

Abstract: An optical information recording medium includes a recording layer in which a track is formed, the track having recording marks linearly arranged thereon. Each recording mark has a dimension corresponding to a reference mark length, which serves as a reference, in a track direction along which the track extends, the dimension being smaller than dimensions of the recording mark in two directions perpendicular to the track direction.

Abstract: An information recording medium according to the present invention includes at least three information recording layers. If the readout power of a laser beam in reading information from an information recording layer L(n) is identified by Pw(n), and if the readout power of the laser beam in reading information from an information recording layer L(n+a) is identified by Pw(n+a), then a base thickness between the information recording layers is determined so that the intensity of the light when the information recording layer L(n+a) is irradiated with a laser beam having the readout power Pw(n) becomes equal to or lower than that of the light when the information recording layer L(n+a) is irradiated with a laser beam having the readout power Pw(n+a).

Abstract: A hybrid LDD includes a read channel to selectively output a read current, a plurality of write channels, each to selectively output a different write current, and an oscillator channel to selectively output an oscillator current. Additionally, the hybrid LDD includes programmable LDD controller that receives the plurality of enable signals from the external controller, and based on the enable signals, controls timing of the currents output by at least the write channels. The programmable LDD controller can also control timing of the currents output by the read and oscillator channels, based on the enable signals. Further and alternative embodiments are also provided.

Abstract: An information reproducing apparatus (1) is provided with: a waveform shaping device (14) for performing waveform shaping on a read signal (RRF) read from a recording medium (100), on the basis of a reference amplification factor; a correcting device (18) for correcting waveform distortion occurring in a read signal corresponding to at least a long mark, of the read signal on which the waveform shaping is performed; and a waveform equalizing device (15) for performing a waveform equalization process on the read signal in which the waveform distortion is corrected, the waveform shaping device arbitrarily increases the reference amplification factor.

Abstract: There is provided an optical recording method for directing a recording pulse train to an optical disc medium to form marks thereon and for recording information as information about the edge positions of said marks and the spaces between marks, the recording pulse train having been created by modulating laser light into plural power levels. The method includes: coding to-be-recorded data into coded data consisting of the combination of marks and spaces; classifying said marks within said coded data on the basis of the mark length and the preceding or succeeding space lengths of the marks; shifting the position of the second pulse edge counted from the end portion of the recording pulse train for forming said marks, depending on the result of said classification, to adjust said recording pulse train; and directing said recording pulse train to the optical disc medium to form said marks thereon.

Abstract: A system and method of controlling data recording process of optical recording medium in a sequential writing are described. The control system comprises an information unit, a data-preparing unit and a recording controller. The information unit generates an information signal. The data-preparing unit prepares the data for recording. The data is then transformed into a writing signal according to the information signal. The recording controller controls the data-preparing unit to adjust the writing signal while acquiring the information signal during a sequential writing. Thus, the recording controller adjusts the writing signal according to the information signal. The data-preparing unit outputs the adjusted writing signal having desired recording area and undesired recording area and the adjusted writing signal is recorded on the optical recording medium during the sequential writing. The adjusted writing signal is outputted to OPU. The OPU performs a recording process of the optical recording medium.

Abstract: An optical disk drive for recording data in accordance with a recording strategy determines a recording strategy of an unknown optical disk through comparatively-simple processing. When a loaded optical disk is an unknown disk, a control section reads a recommended recording strategy from a predetermined area on the loaded optical disk and reads correction parameters corresponding to the loaded optical disk from memory. The control section makes a correction to the read, recommended recording strategy in accordance with the correction parameters, and converts a recording pattern into a recording pulse in accordance with the corrected, recommended recording strategy. After conversion of the recording pattern into the recording pulse, the control section performs OPC and subsequently commences recording of actual data.

Abstract: A method for evaluating reproduced signal wherein when Euclidean distance is calculated by judging the coincidence between a binary bit array and a predetermined evaluation bit array in the evaluation of the quality of reproduced signal, the assumption is made that a continuous 2T count included in a predetermined evaluation bit array is denoted by i and that each evaluation bit array is composed of a main bit array having a bit length of (5+2i); and judgment on whether binary bit arrays include the predetermined evaluation bit array, is concentrated on the coincidence judgment of the main bit arrays.

Abstract: A test-write method for accurately and quickly determining recording conditions, and an apparatus suitable therefor. In a 2T-based strategy, recording pulse conditions are determined by separately test-writing an even-number length mark and an odd-number length mark, and then the relative positions of the even-number length mark and the odd-number length mark at the recording pulse start time are adjusted.

Abstract: Data is recorded in a phase-change optical storage medium having data layers. A first recording pulse sequence is generated for recording to a first data layer located most remote from a beam-incident surface. The first sequence has a recording pulse carrying an erasing power and a recording power rising from the erasing power, and a cooling pulse carrying a bottom power lower than the erasing power. A second recording pulse sequence is generated for recording to a second data layer. The second sequence has recording pulse carrying an erasing power and a recording power rising from the erasing power, a cooling puse carrying a bottom power lower than the erasing power, and an erasing top pulse carrying an erasing top power higher than the erasing power.

Abstract: A recording/reproducing device includes a laser and a laser drive carried by a pickup having a drive for movement. A control controls the drives to irradiate the recording medium with laser pulse sequences forming recording marks having recording mark lengths between a predetermined and maximum lengths, a top section, a last section including a cooling period, and an intermediate period. Heat of mark front edges is controlled by recording parameters for top sections that are classified according to recording mark lengths and recording parameters of the first through the maximum recording mark lengths are classified into a same group. Heat of mark rear edges is controlled by cooling start positions for cooling periods classified according to recording mark lengths. Cooling start positions for a second predetermined mark length through the maximum mark length are classified into a same group. The second mark length is longer than the first mark length.