JPH02210626A - Optical recording and reproducing device - Google Patents

Abstract

PURPOSE:To speed up the operation of the optical recording and reproducing device with simple constitution by using an optical waveguide as a recording medium and reproducing whether or not waveguide light is scattered by a refractive index discontinuous part by plural detectors at the same time. CONSTITUTION:When reproduction is performed, the laser beam 3 from a semiconductor laser 1 for reproduction is guided from an optical coupling part 4 into an optical waveguide recording medium 5 and a part of its waveguide light 7 is scattered by refractive index discontinuous recording parts 9, 9', and 9''' to become leak waveguide light, thereby generating scattered light beams 13, 13' and 13'' outside the waveguide. The scattered light beams are photodetected by photodetectors 17, 17', 17'' and 17''' which are arrayed opposite at intervals and the output of each detector turns on and off or varies according to whether or not there is a bright point, thereby reproducing information recoded on the optical waveguide recording medium 5. The scatter efficiency per bit from the waveguide light 7 to the scattered light 13 is determined by the refractive index ratio, the depth of a pit, and the area of the ellipse at the border of the pit. When a GaAlAs semiconductor laser which generates a continuous output of 10mW is used as a reproduction semiconductor laser 1, the scattered light output per pit is about 0.1muW and sufficient detection is performed by a semiconductor photodetector.

Description

Detailed Description of the Invention [Technical Field] The present invention relates to optical recording using an optical waveguide that records information based on the presence or absence of refractive index discontinuities that cause light scattering and the presence or absence of light absorption and transmission due to photochemical hole burning. It is connected to a playback device.

[Prior Art] A conventional optical recording medium is constructed as shown in FIG. Here, the optical recording medium 100 uses a recording medium as a substrate,
Concave portions 101 with low light reflectance and flat portions 102 with high light reflectance recorded on the substrate surface are arranged in a line, and recording and reproduction is performed while moving the recording medium in the direction of arrow 103. . The ratio of the light reflectance from the flat portion 102 to the concave portion 101 is at most about 1:0.3 to 0.5, and the signal-to-noise ratio of light intensity is by no means good and is difficult to improve.

In addition, in such a recording medium 100, during reproduction, a semiconductor laser is focused on each concave portion 101 or flat portion 102, reflected light is detected, and the time-series signal is reproduced only by movement of the recording medium 100. Access time for playback and recording is limited depending on the moving speed of the medium 100, making high-speed access difficult.

HIt performs optical recording and reproduction using such an optical recording medium.
IEICE technical research report vol. 1.84. No, 2
03, MR84-39. FIG. 9 shows an outline of the optical recording/reproducing apparatus.

In FIG. 9, Ill is a semiconductor laser, 112 to +1
5 is a lens, 116 is a condensing lens installed on the focus actuator, +17 and +18 are half mirrors.
1+19 is a l/2 wavelength plate, 120 is a shaping prism, 12
1 to 123 are photodetectors, 124 is a laser beam recording medium, such as a disk, and 125 is a beam splitter using a prism.

The light from the semiconductor laser 111 passes through the lens 112 . Shaping prism +20, half mirror-117 and condensing lens 1
16 to the recording medium +24, and enters the recess l in FIG.
One recording is made as in ot. Then disk 1
24 is moved to perform the next recording, recesses are provided or removed depending on the information to be recorded, and these are arranged on a line. Here, if the laser beam recording medium 124 is a medium that records information as a change in reflectance, such as a perforated recording medium or a phase change medium, the disk +2
4 is detected by a photodetector +21 as the disk 124 moves, and the optical signal is reproduced as a time-series signal.

On the other hand, in a medium where the laser beam recording medium +24 records information as magnetization reversal, such as a magneto-optical disk, the rotation of the polarization plane of the reflected light by the recording section is separated by the prism beam splitter 125, which is an analyzer, and the separated Light is detected by differential outputs of photodetectors 122 and 123. In this case as well, the optical signal is reproduced as a time-series signal by moving the disk +24.

During such recording and playback, it was recorded on a line! ! l#
The array of 1lol and flat part +02 spirals toward the center of the disk 124 surface, and the above arrangement! It becomes necessary to automatically track +26 according to these arrangements. Furthermore, the above device 126 may be used as a laser beam recording medium 12.
In order to follow the surface blur of No. 4, the condenser lens 116 and the like are moved in the optical axis direction for each array according to the focus error signal to focus.

In such conventional methods, (1) since a light reflection method is used, it is necessary to focus on each recording portion of a recording medium, and the signal-to-noise ratio of the optical signal is poor, resulting in poor reliability.

(ii) Since the optical signal is reproduced for each recorded portion of the recording medium, the time-series signal is reproduced only by the movement of the recording medium, and the cycle time is limited by the moving speed of the recording medium.

(iii) Since the laser oscillator and photodetector are integrated, the device becomes large and heavy, making it difficult to achieve high-speed access and to use multiple heads.

(iv) There are problems such as a large number of optical parts and mechanical parts, complicated optical axis adjustment, and high optical loss in the optical path.

[Objective] Therefore, an object of the present invention is to eliminate the above-mentioned drawbacks and to provide optical recording using an optical waveguide recording medium characterized by having an optical recording section that is an array of a plurality of bright spots that cause light scattering. The purpose is to provide a playback device.

Another object of the present invention is to generate a plurality of bright spots simultaneously using light from - laser oscillators, and by arranging a plurality of photodetectors, it is possible to reproduce a plurality of pieces of recorded information in parallel. The purpose of the present invention is to provide a recording/playback device.

Still another object of the present invention is to solve the above-mentioned problems by using the above-mentioned optical recording/reproducing device, to enable high-speed access in any cycle, to realize wavelength multiplexing high-density recording, and to realize parallel It is an object of the present invention to provide an optical recording/reproducing device which is capable of reproducing a huge amount of information, has a simple configuration, and does not require point-by-point tracking of a recording section.

[Structure of the invention]

In order to achieve such an object, the optical recording and reproducing apparatus of the present invention has a recording section in which a plurality of refractive index discontinuous parts that become bright spots are arranged in an optical waveguide according to the information to be recorded. A recording medium such as a tape, disk, or card in which a plurality of optical waveguides of a predetermined length are arranged, a laser oscillator placed qtm facing one of the optical coupling parts, and a laser oscillator placed qtm facing the recording part of the same optical waveguide. The present invention is characterized in that it includes a member that supports each of a plurality of photodetectors arranged in an FIM manner.

[Example] The present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a principle diagram of the optical recording and reproducing apparatus of the present invention, where l is a semiconductor laser for reproduction, 2 is a lens, 3 is a laser beam, and 4 is an optical coupling part, for example, in this example, a diffraction grating coupling method is used. is used. 5 is an optical waveguide recording medium, 6
is an optical waveguide substrate, 7 is a waveguide light, 8 is an optical recording member,
9. gl, 911+ is a refractive index discontinuous recording section, lO is air or a film serving as a cladding layer, 13.13'.

+3" is scattered light, 16 is unrecorded area, 17.17', 17
Eye 17'' is a photodetector, and 21 is a photodetector support.

The optical waveguide recording medium 5, which is the core part of the optical waveguide, and the cladding layer substrate 6 are made of a polymer material (for example, PMMA, PC, etc.), and the optical refractive index of the optical waveguide recording medium 5 is set to be several percent higher than that of the substrate 6. The guide waveguide in this example is a multimode waveguide ridge type with a height and width of approximately 0.8 μm, but it may also be an embedded type waveguide in which the waveguide is embedded in the substrate 6. In the case of a read-only type optical recording member 8, for example, the same polymeric material as the optical waveguide material is used.

In the case of an additional recording type, an organic dye polymer thin film, which is a material that is perforated by a focused laser beam, can be used, and in the case of an erasing/rewriting type, a chalcogenide-based phase change material can be used.

In this configuration example, a case has been shown in which the refractive index discontinuity portion serving as the optical recording portion is provided in the core portion of the optical waveguide, but the same effect as the present principle can be achieved even if the refractive index discontinuity portion is provided in the cladding layer.

In addition to the diffraction grating coupling method of this example, the optical coupling section 4 may be formed by a taper method or a waveguide end face coupling method.

FIG. 2 shows a plan view of the optical waveguide recording medium 5, and shows that a plurality of discontinuous refractive index recording parts 9, 9'91' arranged in an array are formed of, for example, elliptical bits. There is. Since this bit creates a boundary with air in the optical waveguide, the guided light 7 is scattered at this boundary (which becomes the refractive index discontinuous recording section 9), and scattered light +3 is generated. This bit becomes a bright spot.

At the time of recording, an additional laser oscillation device exclusively for recording is provided, or the laser oscillation device is used together, the laser output is modulated according to the emotion to be recorded, and the recording medium 5 is provided with a refractive index discontinuity according to the above-mentioned material. It is recorded as the presence or absence of part 9, gl, and gl+1.

During reproduction, the laser beam 3 from the reproduction semiconductor laser l is guided into the optical waveguide recording medium 5 through the optical coupling part 4, and a part of the guided light 7 is transmitted to the refractive index discontinuous recording parts g, g r
, g l l + and generates scattered light 13.13', 13'' outside the waveguide as leaked waveguide light.
2 bites! , 1711.17111, and the information recorded on the optical waveguide recording medium 5 is reproduced by turning on, off, or increasing or decreasing the output from each detector depending on the presence or absence of a bright spot.

From guided light 7 to scattered light 13! The scattering efficiency per bit is determined by the refractive index ratio at the bit boundary, the bit search, and the area of the ellipse. The layer was 0.1μ, the long axis of the ellipse was 1.6μm, and the short axis was 0.8μI. For example, if a GaAlAs semiconductor laser with a continuous output of l〇−1 is used as the reproducing semiconductor laser 1, the scattered light output per each bit is approximately 0.1μν, which is sufficiently detectable with a semiconductor photodetector. In this embodiment, a plurality of Si semiconductor photodetectors are used, and a plurality of photodetectors 17.1 are arranged in one dimension.
7', 17''' constitutes 17+11.

Furthermore, for example, the peak output of ultrashort picosecond pulses is 10
If a 0V semiconductor laser is used, the scattered output at each bright spot will be approximately 1μ, and an increase in detection output can be expected. Tweet about the generation of ultra-short picosecond pulses is INT, J
, ELECTRONIC5, 1986, VOL, 60.
No. 1, pages 5-21 provide detailed information.

Currently, the frequency response characteristics of semiconductor photodetectors are 20GHz.
It is relatively easy to do the above. This technique has already been disclosed, for example, in the Proceedings of the 1988 Autumn National Conference of the Institute of Electronics, Information and Communication Engineers, page c-1-53. An oscillator with a pulse width of approximately 20 picoseconds is used for the reproducing semiconductor laser l, and after amplifying the signals from 1.5 million semiconductor photodetectors configured using current technology, the signals are stored in the LSI buffer memory. As a result, the time series signal transfer cycle time from the buffer memory is
It is possible to read up to 5xlO-'' seconds per bit. Therefore, as shown in this example, information in units of 15,000 pieces can be retrieved in 7.5 microseconds.
As long as it is longer than this minimum time, it can be reproduced as time series information with any cycle time.

The optimal light-receiving area of each photodetector is determined by the shape of the bright spot and the distance d from the bright spot. The light intensity distribution of the beam cross section of the scattered light 13 can be calculated from the Fresnel diffraction integral from the bright spot, and can be expressed as a first-order Bessel interval number. As a result, with the elliptical bright spot shape of this example, the optimal light receiving area is 1.6
x5. At Oμ■2, the light receiving distance lad was estimated to be 2-3μ-. In this embodiment, the noise light from adjacent bright spots is less than 1/10, and the signal-to-noise ratio is less than 1:0.1. Each photodetector 17.17', I7'', 1 in FIG.
7''' cross-sectional width is 1.6μ-, and the gap between them is 0.
It is 4 μm.

The entire length of the discontinuous refractive index recording portions 9.9', 9'', arranged in the optical waveguide recording medium 5, was 30 mm'.The pitch length including the unrecorded portion was 2μ. , the total number of refractive index discontinuities is 1.5XIO'.

Therefore, the presence or absence of an optical signal from one photodetector is
Assuming 1 bit, the recording capacity of each optical waveguide recording medium 5 is 15,000 bits, and a total of 15,000 photodetectors are arranged in isolation facing the optical waveguide recording medium 5. I7,17', IT'1.17''' in parallel 1.
Regenerate 50,000 bits of information. 15,000 photodetectors can be arranged and integrated in one dimension along with a signal amplifier on a semiconductor substrate.

The optical attenuation rate of the guided light 7 in such an optical waveguide recording medium 5 is about 1.5/100 of the guided light incident from the optical coupling section 4 even when there are 150,000 bits. approximately the same amount of light enters.

The third diagram shows an embodiment of a wavelength multiplexed optical waveguide recording medium. 22 is a photochemical hole burning material that is applied to the surface of the refractive index discontinuous recording portion 9.9', 9119'' of the optical waveguide to a thickness of several μm. As a photochemical hole burning material, for example, protonated 82 which can be used at the oscillation wavelength of GaAlAs semiconductor laser in the 0.111μ band is used.
A wavelength multiplicity of 10 or more can be easily achieved using a PC or the like. This material has already been described in Chemical Phys.
sics Letters, vol, 114. (198
5) Disclosed on page 491.

Using a wavelength tunable semiconductor laser or a plurality of laser oscillators with different wavelengths, the surface portions of the refractive index discontinuous recording portions 9.91, 911.9111 are irradiated according to the information to be recorded for each wavelength to create a photochemical hole burning portion. 23.23
', 23'', 23''' are formed to perform high-density wavelength multiplexing recording. During reproduction, light from a laser oscillator is guided using the same wavelength as during recording, causing light scattering for each bit. However, the photochemical hole burning section 23.
For each wavelength among 23', 23", and 23"', the part that was irradiated with the laser during recording transmits the scattered light due to light absorption saturation, and the part that was not irradiated with the laser absorbs the scattered light. For example, as shown in the upper part of FIG. 3, each wavelength λ1 . λ2
．． ...For each λ0, transmission (↑ mark) and non-transmission (0 mark) of scattered light occur according to the recorded information. As a result, an optical signal is detected in parallel by the photodetector as digital information of, for example, 0 and 1, and the recorded information is multiplexed and reproduced for each wavelength.

FIG. 4 shows an embodiment of the optical recording and reproducing apparatus of the present invention using an optical digital tape, and 27 is an optical digital tape capable of recording, for example, the optical recording waveguide VA5 shown in FIG. 1 or the wavelength multiplexing shown in FIG. A plurality of optical recording waveguides 5 are arranged diagonally in parallel. 28.28' is the tape feeding rotation support rod, 30.30' is the tape feeding rotation support rod, 32 is a recording-only semiconductor laser oscillator head, 33 is a head running support machine, 34 and 34' are rotation support tools, and 35
．． 35' is a support stand. 37 is a reproduction semiconductor laser oscillator head, 38.38' is a photodetector positioning mechanism section,
40 is a support. Both the recording semiconductor laser oscillator head 32 and the reproducing semiconductor laser oscillator head 37 have a built-in servo mechanism for automatically tracking the optical waveguide recording section.

In this embodiment, the optical digital tape 27 has a tape width of, for example, 20 mm, and the optical recording waveguide 5 is arranged obliquely to secure 15,000 bits over a recording length of 30 mm. During recording, since the system is run only by the lightweight recording-only semiconductor laser oscillator head 32, it is easy to record at a running speed of 20 x 7 seconds or more and a frequency of IOMHz or more. Therefore, a total capacity of 150 Gbit can be recorded. During reproduction, a laser beam is guided from the reproduction semiconductor laser oscillator head 37 to the optical coupling part of the optical recording waveguide to be reproduced, and the servo mechanisms of the photodetector positioning mechanisms 38 and 38' are driven to support the photodetector. Move material 21 slightly! A plurality of photodetectors 17.17', 17'', +
7"' is placed in isolation facing the waveguide recording section 5, the scattered light from the recording section is simultaneously detected, and information is reproduced in parallel. Next, the tape is moved and a different optical recording guide is placed. In this embodiment, the optical waveguide is arranged diagonally with respect to the tape in order to increase as much as possible the number of parallelly reproduced signals that are recorded and reproduced sequentially from the waveguide.

When the information recorded on the optical waveguide is a video signal, the video information is recorded, and when the optical waveguide is used as a file memory like a magnetic tape for a computer, file information is recorded and reproduced.

FIG. 5 shows an embodiment of an optical disc of the optical recording/reproducing apparatus of the present invention, where 41 is an optical reproducing arm, 42 is a support spring, and 43 is an optical disc base material. Optical waveguide recording medium 5
are arranged radially from the center of the optical disk as shown in FIG. 5 on the optical waveguide substrate 6.

The optical reproducing head arm 41 includes a reproducing semiconductor laser oscillator head 37, a photodetector support member 21 that supports a plurality of semiconductor photodetectors arranged one-dimensionally, and a photodetector positioning mechanism that supports the support member 21. 38 and 38'.

In the optical disc of this embodiment, optical recording has been made in advance on the optical waveguide recording medium 5, and the optical disc is a reproduction-only device. - The length of the recording section of the optical waveguide recording medium 5 is 30 s■, and the length of the first
Regeneration is performed using the configuration of the semiconductor photodetector device described in the section with figures. A light absorption or light leakage part, a reflection part, etc. are provided at the final end of the optical waveguide recording part. In this embodiment, since the optical waveguide recording medium 5 is arranged radially on the optical disk disk, the gap between the recording medium waveguides is wider at the outer circumference than at the inner circumference, resulting in waste of the optical disk substrate. Although the optical waveguide recording medium 5 can be arranged in a curved shape, it is difficult to completely eliminate voids.

An example of an endless tape of the optical recording/reproducing apparatus of the present invention that eliminates such drawbacks is shown in the 61st! Shown in I. In Figure 6, 44 is an optical recording medium endless tape, 46.46'
is the tape rotation support rod, 47.47' is the tape guide rod, 4
8 is a tape positioning rotation support rod.

The optical waveguide recording medium 5 is an optical recording medium Endreschi 144.
In this example, the total length of the optical recording medium endless tape 44 is set to 260 mm, and the optical waveguide recording medium 5 The length of the recording section is 30m1, and the first
The area per bit is 1x2 using the optical recording method shown in the figure.
Since it is μs2, the total recording capacity is 3.9 gigabits. The regeneration method is as follows:
1 are arranged as indicated by dotted lines in FIG. 6, and information recorded on the optical waveguide recording medium 5 is reproduced.

FIG. 7 shows an embodiment of an optical card of the optical recording/reproducing apparatus of the present invention, and 49 is an optical card base material. Leading waveguide recording medium 5
are arranged in parallel on the optical waveguide substrate 6, and the optical card base material 4
It is fixed at 9. The optical recording/reproducing device for the optical card is configured by the recording/reproducing device shown in FIG. 4 in accordance with the arrangement of the optical waveguide recording medium 5 of the optical card. By setting the total area of the recording section of the optical card to, for example, 30 x 50 square meters and recording according to the above method, a recording capacity of 750 megabits can be achieved.

[Effects] As is clear from the above, the optical recording and reproducing apparatus of the present invention has the following effects:
Based on a principle different from the light reflection method used in conventional optical discs, etc., we used an optical waveguide as a recording medium to simultaneously reproduce the presence or absence of scattering of guided light from refractive index discontinuities using multiple photodetectors in parallel. Because of these characteristics, it is possible to provide a device with performance exceeding that of current optical recording and reproducing devices.

Moreover, during recording, only a dedicated recording semiconductor laser oscillator is used as the traveling head, so it has the advantage of being significantly smaller and lighter, and capable of high-speed access.

Furthermore, during playback, the playback signal of a predetermined recording section can achieve a playback cycle several orders of magnitude faster than conventional devices, and is capable of high-density recording, as well as inexpensive and highly reliable computer-compatible optical digital recording. It is characterized by being able to provide playback devices, high-definition video recording and playback devices, large-capacity optical card recording and playback devices, and the like.

[Brief explanation of the drawing]

FIG. 1 is a principle diagram of the optical recording and reproducing apparatus of the present invention, FIG. 2 is a plan view of the optical waveguide recording medium 5, FIG. 3 is a side sectional view of the wavelength multiplexing optical waveguide recording medium, and FIG. 4 is the optical recording medium of the present invention. FIG. 5 is a block diagram showing an embodiment of the optical recording and reproducing apparatus of the present invention for an optical disc; FIG. 6 is an endless diagram of the optical recording and reproducing apparatus of the present invention. FIG. 7 is a diagram showing an example of an optical card recording medium of the optical recording/reproducing apparatus of the present invention; FIG. 8 is a plan view showing an example of a conventional 8-media medium; FIG. 9 is a diagram of a conventional optical card recording medium. FIG. 2 is a diagram showing an example of the configuration of an optical recording/reproducing device. ... Semiconductor laser for reproduction, 2 ... Condensing lens, 3 Laser beam, 4 ... Optical coupling section, 5 ... Optical waveguide recording medium, 6 ... Optical waveguide substrate, 7 ... Waveguide light, 8 --- Optical recording member, 9.91,9111 --- Refractive index discontinuous recording section, 1
3.13', +3"...scattered light, 16...
・Unrecorded section. 17.17', +7'', 17LL'...Photodetector, 21...Photodetector support plate, 22I...Photochemical hole burning material, 23.23', 23'', 23'''・... Photochemical hole burning section, 27 ... Optical digital tape, 28.28' ... Tape feeding rotation support rod, 30
．． 30'...The tape retraction rotation support rod, 32
...to the recording-only semiconductor laser oscillator RAD33 ・
・・Head traveling support device, 34, 34′ ・・Rotating support device, 35.35″
...Support stand, 37 ...Semiconductor laser oscillator for reproduction Hefd, 38
, 38' - Fist/photodetector positioning mechanism section, 40
... Support, 5.5', 5" ... Optical waveguide recording medium 41 ...
Radar arm for optical reproduction, 4211... Support spring, 43... Optical disk base material, 44... Optical recording medium endless tape, 46.4
6'...Tape rotation support rod, 47.47'...Tape guide rod, 48...Tape positioning rotation support rod, ・Optical card base material. +00...Optical recording medium, 101...Concave portion with low light reflection, 102...Flat portion with high φ light reflectance, +03.
... Movement direction arrow, 111 ... Semiconductor laser, 112-115 - φφ lens, 116 ... Focus actuator, 117.
118 -φ half mirror 119 φ・l/2 wavelength plate, 120 ... shaping prism, 121-123 ... photodetector, 124 ... laser beam recording medium, 125
...Prism beam splitter. 126 ...Drawing 2 of the device integrated Figure 1:

Claims (1)

[Claims] 1) Recording of the presence or absence of minute refractive index discontinuities that cause light scattering, which is guided light leaking out of the optical waveguide, by arranging a plurality of them in the optical waveguide according to the information to be recorded. an optical waveguide recording medium having a section, a laser oscillation device disposed facing an optical coupling section provided in a part of the optical waveguide which is the recording medium, and a laser oscillation device disposed facing the recording section of the optical waveguide which is the recording medium. An optical recording and reproducing device comprising: a disposed photodetector that receives the scattered light; and a member that supports each of the photodetectors. 2) In the optical recording/reproducing device according to claim 1, the recording portion of the optical waveguide serving as the recording medium has a predetermined length, and a plurality of the optical waveguides are arranged on a tape, a disk, or a card substrate, and The light from the laser oscillation device is guided through the optical coupling part of one of the optical waveguides, and the refractive index discontinuity of the optical waveguide scatters a part of the guided light to form a bright spot of the scattered light. Taking advantage of the fact that The information recorded on the optical waveguide recording medium is reproduced by turning on, off, or increasing or decreasing the output from each photodetector, and then the substrate or the laser oscillation device and the photodetector are moved, and a different An optical recording and reproducing device characterized by sequentially reproducing data from an optical waveguide. 3) In the optical recording and reproducing apparatus according to claim 1, when recording, an additional laser excavation device exclusively for recording is provided,
Alternatively, the laser excavation device is used in combination, the laser output is modulated according to the information to be recorded, and the presence or absence of the refractive index discontinuity is recorded on the recording medium, and at the time of reproduction, the reproduction according to claim 2 An optical recording/reproducing apparatus characterized in that the recorded information is reproduced by a method. 4) In the optical recording/reproducing device according to claim 1, photochemical hole burning is performed on the bright spot surface of the optical waveguide, which is prepared in advance so that all the refractive index discontinuous parts in the optical waveguide are arranged as bright spots. At the time of recording, a variable wavelength laser excavation device or multiple laser oscillation devices with different wavelengths are used to extract the material in the portion corresponding to the bright spot surface of the optical waveguide for each wavelength according to the information to be recorded. irradiate to cause photochemical hole burning, perform wavelength multiplexing recording, and at the time of reproduction, light from a laser excavation device that emits the same multiple wavelengths as used during recording is guided through the optical coupling part for each wavelength, Therefore, the light from each bright spot is transmitted or absorbed depending on the presence or absence of photochemical hole burning in the material. An optical recording and reproducing device that detects information using a photodetector and multiplexes and reproduces recorded information for each wavelength.