CN1081376C - Waveguide near-field writing and reading head for optical record carrier - Google Patents
Waveguide near-field writing and reading head for optical record carrier Download PDFInfo
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- CN1081376C CN1081376C CN 99116336 CN99116336A CN1081376C CN 1081376 C CN1081376 C CN 1081376C CN 99116336 CN99116336 CN 99116336 CN 99116336 A CN99116336 A CN 99116336A CN 1081376 C CN1081376 C CN 1081376C
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- semiconductor laser
- wave guide
- passive wave
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Abstract
The present invention relates to a waveguide near-field optical recording writing and reading head which comprises a light receiving device, a floating block, a semiconductor laser and a tapered passive waveguide coupled with the semiconductor laser, wherein the light outputting end of the tapered passive waveguide is positioned at the lowest point of the floating block, and the section area of the light outputting port of the tapered passive waveguide is smaller than that of the back end face of the semiconductor laser; the core layer of the tapered passive waveguide is made from high-refractive index material, the coating layer of the tapered passive waveguide is made from low-refractive index material, the difference between the two refractive indexes is higher than or equal to 0.05; the semiconductor laser can be a T-shaped semiconductor laser with an F-P cavity as well as a DFB semiconductor laser. The present invention can reduce the spot size to be decade nanometers so as to maximally increase optical recording density and track seeking speed.
Description
The present invention is a kind of waveguide near-field writing and reading head for optical record carrier, finishes information stores according to relative motion between record carrier and the sensor, reads and writes with optical means.
U.S. Pat 5689480 (November 18 1997 day for announcing) utilizes the cross bath that carves on the silicon chip to constitute waveguide, and the groove inside surface is a metallic reflector, is air or high index of refraction material in the groove.This technical scheme can obtain higher recording density, but the shortcoming one that exists is that light source separates with waveguide, adopts Mechatronic Systems to follow the tracks of and focuses on the Dynamic Coupling that realizes waveguide, makes that the optical read/write head quality is big, and seeking speed is difficult to improve; The 2nd, though adopt the cruciform waveguide can obtain less record hot spot, in the acquisition of signal process, intertrack crosstalk and intersymbol interference are introduced in cruciform waveguide meeting, and this all can reduce recording density.In fact the amplitude of cruciform waveguide raising recording density is very limited.
U.S. Pat 5199090 (accuse out day on March 30th, 1993) provide a kind of on magnet-optical medium the magneto-optic read/write head of record and reading and recording.This device is by a slider pad and be positioned at optical waveguide structure, light source and detector on the slider pad, adds a solenoid again and forms.Its waveguiding structure comprises a slab guide, collimator objective and diffraction object lens; Semiconductor laser and waveguiding structure adopt direct integration mode coupling.The light beam that sends from light source enters slab guide through collimator objective, acts on the recording medium after diffraction lens focuses on again.This invention utilizes slab guide and diffraction lens to focus on and obtains minimum spot, and the size of a direction of spot can be less by the decision of slab guide thickness; The size of another direction is by numerical aperture (N.A.) decision of diffraction lens, because diffraction lens N.A. value is less, the spot size on this direction is bigger, and spot size is only less in the slab guide direction.Therefore, this scheme can not be reduced to facula area enough little, and spot size is more than 100 nanometers, and the potentiality that can improve recording density are limited.
The purpose of this invention is to provide and a kind ofly can further dwindle spot size and the little Waveguide near-field optical recording read-write equipment of quality, thereby improve recording density and seeking speed.Be to realize this purpose, the shape of specialized designs waveguide of the present invention and structure, and semiconductor laser and waveguide directly be coupled or assemble coupling.
Realize the waveguide near-field writing and reading head for optical record carrier of the object of the invention, comprise sensitive device, slider pad, semiconductor laser and passive wave guide; Semiconductor laser and passive wave guide are coupled, and passive wave guide bright dipping end is positioned at the minimum point of slider pad, it is characterized in that:
(1) described passive wave guide is that taper passive wave guide, its xsect hypotenuse shape can be straight-line segment, broken line or curve, it and semiconductor laser coupling form taper passive wave guide integrated device, and the bright dipping port cross-sectional area of this taper passive wave guide integrated device is less than the area of section of semiconductor laser rear end face in the taper passive wave guide integrated device;
(2) sandwich layer of taper passive wave guide is a high-index material, and covering is a low-index material, the refringence of core material and clad material 〉=0.5.
Above-mentioned waveguide near-field writing and reading head for optical record carrier, described semiconductor laser can be a T shape F-P (Fabry-Perot) cavity semiconductor laser, its bright dipping end is a T shape, bright dipping end T shape plane of structure is coated with reflectance coating, only in the center section bright dipping, all the other structures are identical with common short wavelength semiconductor laser, the direct integrated coupling or utilize fine manufacturing technology assembling coupling on same substrate of described taper passive wave guide and T shape F-P cavity semiconductor laser.
Above-mentioned waveguide near-field writing and reading head for optical record carrier, described semiconductor laser also can be a distributed feedback type semiconductor laser, the direct integrated coupling or utilize fine manufacturing technology assembling coupling on same substrate of described taper passive wave guide and distributed feedback type semiconductor laser.
The waveguide near-field writing and reading head for optical record carrier of aforementioned several situations, described sensitive device can comprise diffraction lens, reflecting prism and optical signal detecting element, diffraction lens is positioned on the slider pad, reflecting prism is positioned on the access arm and the diffraction lens corresponding end, the optical signal detecting element is positioned at an end relative with reflecting prism on the access arm, and this moment, corresponding recording medium was magneto-optic or phase change medium.
The waveguide near-field writing and reading head for optical record carrier of aforementioned several situations, described sensitive device also can only be made of the optical signal detecting element that is positioned on the slider pad, and this moment, corresponding recording medium should be phase change medium.
Waveguide near-field writing and reading head for optical record carrier provided by the invention since the bright dipping port cross-sectional area of taper passive wave guide integrated device less than the area of section of semiconductor laser rear end face in the taper passive wave guide integrated device, the difference of the refractive index of tapered transmission line core material and clad material is enough big, spot size is further dwindled, can reach tens nanometers, improve the recording density of writing and reading head for optical record carrier greatly; The direct integrated coupling of taper passive wave guide and semiconductor laser or utilize fine manufacturing technology assembling coupling in the taper passive wave guide integrated device reduces the quality of read/write head, can improve seeking speed.
Fig. 1 is the vertical view of waveguide near-field writing and reading head for optical record carrier of the present invention;
Fig. 2 is the cut-open view of Fig. 1 along the E-E section;
Fig. 3 utilizes T shape F-P cavity semiconductor laser and the taper passive wave guide taper passive wave guide integrated device that direct integrated coupling forms on same substrate;
Fig. 4 be Fig. 3 along A-A to cut-open view;
Fig. 5 be Fig. 4 along B-B to cut-open view;
Fig. 6 utilizes distributed feedback type semiconductor laser and the taper passive wave guide taper passive wave guide integrated device that direct integrated coupling forms on same substrate;
Fig. 7 be Fig. 6 along C-C to cut-open view;
Fig. 8-1, Fig. 8-2, Fig. 8-3 be Fig. 7 along D-D to cut-open view, they represent three kinds of difformities of taper passive wave guide respectively.
Fig. 9 is a kind of optical recording system that is made of waveguide near-field writing and reading head for optical record carrier illustrated in figures 1 and 2.
Figure 10 is the another kind of optical recording system that is made of waveguide near-field writing and reading head for optical record carrier illustrated in figures 1 and 2.
Further describe enforcement state of the present invention below in conjunction with accompanying drawing.From Fig. 1 and Fig. 2, can find out, the light signal that sensitive device 1 is accepted by recording medium 5 transmission, taper passive wave guide 3 and semiconductor laser 4 couplings, the bright dipping end of passive wave guide 3 is positioned at the minimum point of slider pad 2, can write light signal to recording medium 5.
At the taper passive wave guide integrated device shown in Fig. 3-Fig. 7 and Fig. 8-1,8-2, the 8-3, can take following method to be made.
1. take hypertrophy technology or selective corrosion technology to make tapered transmission line.
(1) hypertrophy technology: deposit and make by lithography fillet shape low-index material 8 on n-GaAs or Si substrate 7 earlier, this material can be MgF
2, refractive index n=1.38; Again on substrate the growth high-index material 9, as GaP film, n=3.4; Or the ZnS film, n=2.35; Or the AlGaInP film, n=3.3.Can on the fillet of low-index material 8, cover high refractive index film 9 by the hypertrophy process, utilize photoetching process again, remove the outer high-index material of fillet, and then on substrate and high-index material fillet, deposit low-index material 8, obtain the waveguide of big refringence.
(2) selective corrosion technology: one deck selective corrosion layer of between high-index material layer 9 and substrate 7, growing earlier, erode the middle layer then, deposit low-index material 8 at last again.
Fig. 8-1, Fig. 8-2, Fig. 8-3 have enumerated several shapes of the horizontal sanction face of tapered transmission line, and tapered transmission line goes out the sanction face area of optical port 3-1 area of section less than semiconductor laser rear end face 4-1.Shown in Fig. 8-1, when selecting for use λ to be the semiconductor laser of 680nm, tapered transmission line bright dipping end width 90nm, semiconductor laser rear end face width 180nm, core material is ALGaInP, clad material MgF
2, tapered transmission line length 3.4 μ m.
2. tapered transmission line 3 forms the tapered transmission line integrated device with the semiconductor laser coupling.
(1) T shape F-P cavity semiconductor laser and tapered transmission line 3 couplings.See Fig. 3-Fig. 5, when semiconductor laser 4 is selected T shape F-P cavity semiconductor laser for use, the tapered transmission line of preparation can be directly integrated with this semiconductor laser on substrate 7, except that shape of cross section, the structure of this laser instrument and common F-P chamber short wavelength semiconductor laser are basic identical, comprise n-metal electrode 10, P metal electrode 11, ridge waveguide 12 can adopt P-GaAs, current barrier layer 13 is P-GaInP, P-limiting layer 14 materials are P-ALGaInP, active layer 15GaInP, and n-limiting layer 16 is n-ALGaInP.Its bright dipping end of T shape F-P cavity laser is a T shape, and bright dipping end T shape plane of structure 4-2 is coated with reflectance coating.
(2) also can select DFB (distributed feed-back formula) semiconductor laser and tapered transmission line 3 couplings for use.See Fig. 6, Fig. 7, Fig. 8-1, Fig. 8-2, Fig. 8-3.In these several accompanying drawings, each several part label and explanation are identical with above stated specification, only change semiconductor laser 4 into the dfb semiconductor laser instrument, and among Fig. 7,17 is the feedback grating of dfb semiconductor laser instrument.
Waveguide near-field writing and reading head for optical record carrier among the present invention can constitute the optical recording system in many ways.Be two kinds of constituted modes simple in structure, that degree of being practical is high below.
In optical recording system shown in Figure 9, the sensitive device 1 in the waveguide near-field writing and reading head for optical record carrier comprises a diffraction lens 18, a reflecting prism 19 and an optical signal detecting element 20.Two waveguide near-field writing and reading head for optical record carrier are installed in the optical recording system by correspondence shown in Figure 9, and the distance between the surface that goes out optical port and recording medium 5 of tapered transmission line 3 is within the near field of light scope.Tapered transmission line 3 or 3 ' the optical port that goes out aim at the opposing party's diffraction lens 18 ' or 18.Voice coil motor 22 is a radially tracking drive motor of optical head, semiconductor laser 4 produces laser beam and enters tapered transmission line 3, tapered transmission line 3 utilizes big refringence that the laser beam spot that enters is reduced to enough little, luminous point affacts above the recording medium 5, and by opposite slider pad 2 ' diffraction lens 18 ' luminous point is become parallel light emergence, utilize reflecting prism 19 on the access arm 21 with light reflected light signal detection component 20 again, to realize the read-write capability of optical recording media.Another waveguide near-field writing and reading head for optical record carrier principle of work on its opposite is identical therewith.Recording medium 5 in this optical recording system can be magnet-optical medium or phase change medium.
When recording medium was phase change medium, waveguide near-field writing and reading head for optical record carrier can constitute optical recording system as shown in figure 10.Sensitive device in the waveguide near-field writing and reading head for optical record carrier only comprises an optical signal detecting element 6 that is positioned on the slider pad 2.The constituted mode of this optical recording system is identical with principle of work and Fig. 9, just with side's tapered transmission line 3 or 3 ' shine the luminous point on the recording medium 5, directly enters the optical signal detecting element 20 of another side ' or 20, finishes its read-write capability.
Claims (5)
1. a waveguide near-field writing and reading head for optical record carrier comprises sensitive device, slider pad, semiconductor laser and passive wave guide; Semiconductor laser and passive wave guide are coupled, and passive wave guide bright dipping end is positioned at the minimum point of slider pad, it is characterized in that:
(1) described passive wave guide is that taper passive wave guide, its xsect hypotenuse shape can be straight-line segment, broken line or curve, it and semiconductor laser coupling form taper passive wave guide integrated device, and the bright dipping port cross-sectional area of this taper passive wave guide integrated device is less than the area of section of semiconductor laser rear end face in the taper passive wave guide integrated device;
(2) sandwich layer of taper passive wave guide is a high-index material, and covering is a low-index material, the refringence of core material and clad material 〉=0.5.
2. waveguide near-field writing and reading head for optical record carrier as claimed in claim 1, it is characterized in that described semiconductor laser is a T shape F-P cavity semiconductor laser, its bright dipping end is a T shape, bright dipping end T shape plane of structure is coated with reflectance coating, only in the center section bright dipping, all the other structures are identical with common short wavelength semiconductor laser, the direct integrated coupling or utilize fine manufacturing technology assembling coupling on same substrate of described taper passive wave guide and T shape F-P cavity semiconductor laser.
3. waveguide near-field writing and reading head for optical record carrier as claimed in claim 1, it is characterized in that described semiconductor laser is a distributed feedback type semiconductor laser, the direct integrated coupling or utilize fine manufacturing technology assembling coupling on same substrate of described taper passive wave guide and distributed feedback type semiconductor laser.
4. as claim 1,2 or 3 described waveguide near-field writing and reading head for optical record carrier, it is characterized in that described sensitive device comprises diffraction lens, reflecting prism and optical signal detecting element, diffraction lens is positioned on the slider pad, reflecting prism is positioned on the access arm and the diffraction lens corresponding end, and the optical signal detecting element is positioned at an end relative with reflecting prism on the access arm.
5. as claim 1,2 or 3 described waveguide near-field writing and reading head for optical record carrier, it is characterized in that described sensitive device only is made of the optical signal detecting element that is positioned on the slider pad, this moment, corresponding recording medium should be phase change medium.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 99116336 CN1081376C (en) | 1999-02-01 | 1999-02-01 | Waveguide near-field writing and reading head for optical record carrier |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 99116336 CN1081376C (en) | 1999-02-01 | 1999-02-01 | Waveguide near-field writing and reading head for optical record carrier |
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| Publication Number | Publication Date |
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| CN1225488A CN1225488A (en) | 1999-08-11 |
| CN1081376C true CN1081376C (en) | 2002-03-20 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN 99116336 Expired - Fee Related CN1081376C (en) | 1999-02-01 | 1999-02-01 | Waveguide near-field writing and reading head for optical record carrier |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP4079274B2 (en) * | 2002-07-16 | 2008-04-23 | 富士通株式会社 | Multilayer optical recording medium and storage device |
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- 1999-02-01 CN CN 99116336 patent/CN1081376C/en not_active Expired - Fee Related
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| CN1225488A (en) | 1999-08-11 |
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