JPH06301072A - Image transmission device - Google Patents

Abstract

PURPOSE:To provide an image transmission device which can efficiently transmit image patterns and two-dimensional optical data directly in the state of light in parallel, facilitates alignment, does not require the use of optical fibers of the same characteristics like heretofore and makes it possible to obtain image patterns of sufficient transmission light intensity. CONSTITUTION:This direct image transmission device has a photorefractive crystal (hereafter described as PRC)2b for generating phase conjugation waves by self-pumping, a spatial optical modulator 12 and transmission side optical systems 3g, 10 for writing image signals in this PRC2b, a laser beam source 1b for driving the PRC2b, transmission media 3f, 9a for transmitting the image signals and signal reception side optical systems 7b, 3e, 6b for imaging the phase conjugation waves. An EARS (exciton absorption and reflection switch) is usable in place of the spatial optical modulator 12 and a plane light emitting laser array is usable for the transmission side optical systems.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention directly and optically outputs two-dimensional data represented by an image pattern or a light pattern.
The present invention also relates to an image transmission device that transmits in parallel.

[0002]

2. Description of the Related Art At present, image signals are usually transmitted as electric signals as frame signals by replacing two-dimensional data with time by the NTSC system or the like. Therefore, in this case, the resolution and frame rate that can be transmitted are limited by the band of the electric signal, and the resolution and frame rate are exclusively about 100,000 pixels and 30 frame rate, respectively.
It was about ms.

In order to improve this, there is a technique in which an image signal is transmitted directly in parallel through an optical fiber or an optical waveguide as it is. This technique is described in, for example, the literature (B.
Fischer and S.M. Sternklar,
'Image transmission and in
terferometry with multimo
de fiberrs using self-pump
ed phase conjugation, 'Ap
plied Physics Letters, vo
l. 46, no. 2, pp. 113-114 (198
5)) is known. FIG. 1 shows the configuration of a conventional example disclosed in this document and the like. In the figure, 1c is a laser light source (for example, krypton laser, wavelength 647 nm), 2c is a photorefractive crystal (hereinafter abbreviated as PRC) (for example, BaTiO ₃ or BTO), 3h, 3i and 3
j is a lens, 5b is an image pattern, 6c is a screen,
7c is a half mirror, 9b is a multimode optical fiber,
Reference numeral 23 is a collimator, and 24 is a concave mirror.

The operation of the apparatus shown in FIG. 1 will be described along the flow of light rays. The laser light emitted from the laser light source 1c has its beam diameter expanded by the collimator 23 and enters the image pattern 5b. The light ray transmitted through this image pattern 5b is a half mirror 7c, a lens 3h, and a multimode optical fiber 9
It is incident on the PRC 2c via b and the lens 3i.
This incident light ray is called E1. The lens 3h is arranged so that the laser light is incident on the optical fiber 9b, and the lens 3i is arranged so as to make the light emitted from the optical fiber 9b substantially parallel light. Now, a part of the incident light is scattered in the PRC 2c and is directed to the concave mirror 24, as indicated by E2 in FIG. The concave mirror 24 is arranged so that the scattered light is exactly returned to the PRC 2c, and the reflected light E3 from the concave mirror 24 is provided.
Travels exactly in the opposite direction of the incident ray E2. At this time, PRC
Two rays (E2, E3) in 2c interfere with each other, and P
A refractive index distribution proportional to the intensity of interference fringes is created inside the RC.
Based on this refractive index distribution, the reflected light ray E3 returns as a light ray E4 in the direction in which the incident light ray E1 came. At this time, the light rays E1 and E4 are conjugate. The conjugate light E4 propagates in the opposite direction on the same path as E1. That is, the light ray E4 returns to the lens 3i, the optical fiber 9b, the lens 3h, and the half mirror 7c. The light ray E4 reflected by the half mirror 7c passes through the lens 3j and enters the screen 6c. The light E4 returning from the optical fiber 9b is originally conjugate with the incident light E1. Therefore, if the half mirror 7c is excluded, the light E4 returns to the image pattern 5b. Here, the half mirror 7c is used to observe the image pattern 5b.
Is used. The function of the lens 3j is to magnify and project the reproduced image of the image pattern 5b on the screen 6c. According to this structure, the image pattern 5b cannot be reproduced by the optical fiber 9b on the right side of the drawing, but is reproduced again on the screen 6c.

However, in this conventional method, the image distortion caused by the phase fluctuation of the optical fiber is compensated for by reciprocating the light through the same path. Therefore, the image is correctly reproduced at the place where the transmitted image exists. Was limited to. Therefore, such a thing cannot be said to be a substantial transmission. There is also a proposal to transmit an image by using exactly the same optical fiber, but it is not practical as a system and has not been realized so far.

As another method for transmitting a one-way image using a phase conjugate mirror, there is another "image transmission device" Japanese Patent Application No. 4-36626 proposed by the present applicant. This is an unpublished technology, but the image signal is converted into a spatial light modulator (hereinafter referred to as S
By writing on a phase conjugate mirror (abbreviated as LM), the above-mentioned drawback is overcome and one-way transmission is enabled. However, in this method, since the SLM used as the phase conjugate mirror has no amplifying action, the transmitted light is weak and the image is not sharp. Furthermore, this method has another problem as follows. That is, the reference light and the phase conjugate wave of the reference light are required to generate the phase conjugate wave, but the phase conjugate wave of the normal reference light divides the reference light into two, and one of the light rays is divided by a mirror or the like. It was regarded as a phase conjugate wave by proceeding in exactly the opposite direction to the other. However, it is very difficult to align the optical system so that the two light beams are exactly overlapped and continue to operate stably for a long time.

[0007]

As described above,
In the conventional direct image transmission technology using light, there were drawbacks such as the fact that the same optical fiber had to be prepared, the transmitted light intensity was small and the image was not clear, and the alignment of the optical system was difficult. .

The present invention has been made in view of such a background, and provides an image transmission device which is capable of efficiently transmitting an image pattern or two-dimensional optical data directly in parallel as light and with easy alignment. The purpose is to

[0009]

In order to achieve the above object, the present invention provides a photorefractive crystal for generating a phase conjugate wave by self-pumping, an optical modulator for writing an image signal in the photorefractive crystal, and a transmission-side optical element. System, a laser light source that drives the photorefractive crystal, a transmission medium that transmits the phase conjugate wave of the image signal generated from the photorefractive crystal, and an image of the phase conjugate wave transmitted by the transmission medium And a receiving side optical system.

Further, in a preferred aspect of the present invention, the optical modulator is any one of a spatial light modulator, an exciton absorption / reflection switch, and a self-electro-optical effect device. Is.

[0011]

In the present invention, a self-pumpable PRC (photorefractive crystal) is used as a phase conjugate mirror,
By using an optical modulator such as an SLM (spatial light modulator) as an image input means, parallel direct image transmission of an image pattern or two-dimensional optical data can be efficiently realized. In particular, according to the present invention, it is not necessary to use an optical fiber having the same characteristics as in the prior art, and an image pattern having a sufficient transmitted light intensity can be obtained.

[0012]

Embodiments of the present invention will now be described in detail with reference to the drawings.

(First Embodiment) The first embodiment of the present invention is an example of a structure for making an image pattern visible through frosted glass. A first embodiment of the present invention will be described with reference to FIG. In the figure, 1a is a laser light source, 2a is a PRC (photorefractive crystal) of BTO crystal, 3a, 3b and 3c are lenses, 4 is frosted glass as a strained object,
5a is an image pattern, 6a is a screen, and 7a is a half mirror. More specifically, the laser light source 1a
Is a krypton (Kr) ion laser with an oscillation wavelength of 647 nm, an output of 300 mW, and a coherent length of 10 m or more. The loci of rays from the laser light source 1a to the PRC 2a are as follows. The laser beam is emitted from the laser light source 1a, passes through the lens 3a, the half mirror 7a, the frosted glass 4 and the lens 3b in this order, and enters the PRC 2a. The lens 3a acts as a collimator that widens the beam diameter of the light beam. The light beam is scattered by the frosted glass 4, but the lens 3b
Thus, the diameter is reduced again and the light enters the PRC 2a.

Prior to explanation of image reproduction, the principle of phase conjugate wave generation based on self-pumping in this configuration will be described. The ray E1 incident from the lens 3b is PRC2a.
Incident on and propagates in the crystal. If there is a scattering center at the point indicated by x here, the light ray is separated into a straight component (broken line) and a scattered component (E2). Image pattern 5
When a is not yet attached, ray E2 reflects twice in PRC2a and travels toward point y as ray E3 'if the condition of total internal reflection is satisfied. That is,
The rays E1 and E3 'interfere with each other at the point y, and a refractive index distribution is generated in the PRC 2a corresponding to the interference fringes.
As a result, the ray E1 takes a new path in addition to the ray E2. This new path is the path of E2 ', E3, E4. The following combinations of rays (E1, E4), (E2, E3), (E2 ', E) that occur at this time
3 ') are all conjugate waves. That is, the emitted light ray E4 that is conjugate with the incident light ray E1 returns to the lens 3b and the frosted glass 4 again. The profile of this light beam passes through the half mirror 7a and the lens 3c, and then passes through the screen 6a.
Observed above.

The behavior of the light rays when the image pattern 5a is attached to the PRC 2a under the condition of generating the phase conjugate wave is as follows. The image pattern 5a is a suitable aluminum pattern deposited on a glass substrate. This image pattern 5 using matching oil
By sticking a and the PRC 2a, the aluminum part of the image pattern 5a totally reflects the light rays, and the other part goes out from the PRC 2a. At this time, since the image pattern is superimposed on the light ray E4 returning from the PRC 2a, the image is reproduced on the screen 6a.

It has been confirmed that with the above-mentioned constitution, the image pattern is sufficiently observed even through the frosted glass.

(Second Embodiment) A second embodiment of the present invention is an example of a structure for transmitting an actual object image through an optical fiber in real time. The structure is shown in FIG. In the figure, 1b is a laser light source, 2b is a PRC, 3d to 3g are lenses, 6b is a screen, 7b is a half mirror, 9a is a multimode optical fiber, 10 is a halogen lamp, 11 is a pulse power supply, and 12
Is a spatial light modulator (hereinafter abbreviated as SLM), and 25 is an object. The difference between this example and the above-described first example of the present invention is that the strained object is from the frosted glass 4 to the optical fiber 9
changed to "a" and the image pattern is an optical address type SL
This is a replacement of image input by M12. The parts and equipment used are shown below. The laser light source 1b is Kr
The ion laser is the same as that of the first embodiment. P
RC2b is also a BTO crystal. The optical fiber 9a is a step index multimode optical fiber having a length of 2 m and a core diameter of 600 μm.

The SLM 12 is a photo-addressable SLM in which a ferroelectric liquid crystal and a photoconductive film are combined. 4 and 5 are views showing the structure of the SLM 12, FIG. 4 is a top view, and FIG.
FIG. 6 is a cross-sectional view taken along the section line C-C ′ shown in FIG. 4. In the figure, 101a and 101b are quartz glass substrates and 10
2 is a ferroelectric liquid crystal layer (using ZLI-4003 manufactured by Merck & Co., Inc.), and 103a to 103c are indium tin oxides (I
TO) is a transparent electrode, and 104a and 104b are alignment films formed by rubbing polyvinyl alcohol.
5 is a dielectric mirror (reflectance 99% at a wavelength of 647 nm) composed of 7 pairs of alternating films of TiO ₂ and SiO _2.
Reference numeral 06 is a hydrogenated amorphous silicon photoconductive film formed by a plasma CVD method, 107 is a silver paste, 108 is an epoxy sealant, 109a and 109b are lead electrodes, and 110 is a ceramic spacer. The pulse power supply 11 and the SLM 12 are connected to the lead electrodes 109a and 10a.
It is connected via 9b. In addition, the ferroelectric liquid crystal layer 1
No. 02 has a thickness of 1.1 μm and is in a surface-stabilized state.
The thickness of the ferroelectric liquid crystal layer 102 is calculated by the following formula.

[0019]

## EQU1 ## Δnd = λ / 4 (Δn is the birefringence of the liquid crystal, d is the thickness of the liquid crystal, λ is the wavelength of the reading light), and the tilt angle of the liquid crystal is 22.5 °. is there. Each constant is Δn = 0.1 at room temperature
5, d = 1.1 micron, λ = 647 nm. At this time, the liquid crystal rotates the polarization of the incident light as it is or by 90 ° depending on whether the applied voltage is positive or negative.

The SLM 12 is electrically a series circuit of a photoconductive film, a dielectric mirror, and a ferroelectric liquid crystal. Based on FIG. 5, the current flows vertically, and the leakage of the current to the horizontal is very small. The conductivity of the photoconductive film 106 becomes extremely large when irradiated with the writing light, so that the voltage applied to the ferroelectric liquid crystal layer 102 can be controlled by the intensity of the writing light. Therefore, the positive voltage (+1
5V, 2ms) and by applying a negative voltage pulse (-15V, 500μs) at the time of writing, the polarized light is rotated by 90 ° in the portion not irradiated with the writing light, and the polarized light is rotated in the portion irradiated with the writing light. does not change.

Returning to the image transmission apparatus of FIG. 3, description will be made. The light emitted from the laser light source 1b passes through the lens 3d and the optical fiber 9
The core diameter of a is 600 μm and the light is incident on the optical fiber 9a. The light beam emitted from the optical fiber 9a is collimated by the lens 3f and enters the PRC 2b. After that, the operating principle is basically the same as that of the first embodiment described above, but the SL arranged so that the image can be input in real time.
The generation principle of M12 and the phase conjugate wave will be described in more detail. FIG. 6 is a detailed diagram around the PRC 2b and the SLM 12. In this drawing, the lens 3g of the writing optical system and the halogen lamp 10 are omitted, and the object 25 is simply replaced with a black and white pattern 25 '. Further, since the SLM itself has a considerably complicated structure and the details have already been described, some components such as the alignment film are omitted in the drawing. Further, it is assumed that the incident light from the optical fiber 9a is horizontally polarized light. In the figure,
The hatched wavy line that overlaps the ray indicates the polarization direction.
Now, the rays in PRC2b are scattered at the point x,
It travels as a ray of E21 and is incident on the z point of the SLM 12 by total reflection on the surface of the PRC 2b. As described above, since the SLM 12 does not change the polarization of the reading light in the portion irradiated with the writing light, the reflected light at the point z goes to the point y in the PRC 2b as it is horizontally polarized. At this time, at the point of y, due to the interference between the incident light ray E1 and the reflected light ray E3 ', a refractive index distribution according to the intensity is generated in the PRC 2b. Therefore, a part of the light ray E1 is changed to the light ray E2 'or the light ray E3, and the light rays E21 and E
Proceed in the opposite direction from 3 ', and finally publicize as ray E4
Exit from C2b. On the other hand, the phase conjugate wave is not generated in the portion of the SLM 12 which is not irradiated with the writing light as follows. The ray E22 scattered at the point x is PRC
It is incident on the point z'on the SLM 12 by total reflection on the surface 2b. Since the liquid crystal molecules of the ferroelectric liquid crystal layer 102 are oriented at an angle of 22.5 ° from the polarization plane in this portion (the portion where the writing light is not irradiated), the polarization plane of the reflected light is rotated by 90 °, It becomes vertically polarized light. This vertically polarized ray intersects the ray E1 at the point y'in the PRC 2b, but it does not cause interference because the polarization directions do not match each other. Therefore, the phase conjugate wave is not generated, and the light ray is no longer returned from the image of this portion.

Similar to the first embodiment, the E4 ray of this embodiment passes through the lens 3f, the optical fiber 9a, the half mirror 7b and the lens 3e in FIG. 3 and forms an image on the screen 6b.

With this construction, when an m-length direct image transmission device was assembled and transmitted while moving the object 25, the image could be transmitted at a sufficiently high speed and the movement of the object 25 was sufficiently followed. Further, a small device using a visible light laser diode having a wavelength of 670 nm and an output of 30 mW was also prototyped as the laser light source 1b, but a clear image could be similarly transmitted. In addition to the SLM described above, an optical modulator having a superlattice quantum well structure and an array element thereof, which will be described later, can be applied as the image input means.

(Third Embodiment) In the image transmitting apparatus of the present invention, not only the image is transmitted but also the data can be transmitted in parallel by a two-dimensional optical pattern. As a data input / output means, an optical modulator having a superlattice quantum well structure and its array element (for example, EARS (C.
Amano et al., 'Novell photonic sw
itch arrays consulting of
vertically integrated mu
ltipple-quantum reflexio
n modulators and phototra
nsistors: exciton absorpt
Ive reflection switch, 'I
EEE Photonics Technology
Letters. Vol. 3, No. 8, pp. 736
-738 (1991) and SEED (D.A.B.Mil)
ler, 'Quantum-well self-el
actor-optic effect device
s, 'Optical and Quantum E
electronics Vol. 22, pp. S61-
S98 (1990)) or the like can be used. FIG. 7 shows a third embodiment of the present invention using the above EARS.
In this embodiment, a planar quartz waveguide is used as the transmission line. In the figure, 2d is PRC, 3j and 3k are lenses, 7d is a half mirror, 13 is an EARS (exciton absorption / reflection switch), 14 is a laser diode, 15
Is a planar quartz waveguide, 16 is a control power supply, 17 is a surface emitting laser array, and 18 is a photodetector array. In this example, the light pattern displayed by the surface emitting laser array 17 controlled by the control power supply 16 is changed to the PRC 2d, the lens 3k, the planar quartz waveguide 15, the half mirror 7d, the lens 3l, and the photodetector array 18. Direct transmission as is. The EARS 13 will be described in detail later. The laser diode 14 has an oscillation wavelength of 850.
It is used as a laser light source with a wavelength of 50 nm and an output of 50 mW. The surface emitting laser array 17 is also a laser diode array having an oscillation wavelength of 850 nm.

The third embodiment of the present invention is basically the same as the second embodiment of the present invention except for the differences in the laser light source, the optical waveguide and the optical modulator. The operation principle will be described with reference to FIG. The PRC 2d is similar to the previous first and second embodiments in that the BTO crystal operates at this wavelength as well, so the BTO
Crystals were used. First, the detailed structure (1 bit) of the EARS 13 will be described with reference to FIG. First, as an outline, 201 is a device substrate, 202, 203 and 204.
Is a heterojunction phototransistor, 210, 211 and 212 are pin diodes, of which 210 is a mirror and 211 and 212 are optical modulators. Electrically, the voltage VB is applied to the heterojunction phototransistors 202 to 204 and the pin diodes 210 to 212 having the parallel structure via the resistor 207. The details are as follows. The substrate 201 is n-type AlGaAs (thickness 3
00 μm), 202 is an n-type Al _0.3 Ga _0.7 As (0.5 μm thick) emitter layer, 203 is a p-type GaAs (0.75 μm thick) base layer, 204 is an n-type GaAs (4 μm thick) collector layer, 210 is n-type Al _0.3 Ga _0.7 A
s (629 angstrom per layer) and n-type AlA
s (715 angstrom per layer) alternating 25
Periodically stacked distributed Bragg reflector, 211 is GaAs
(100 angstrom per layer) and Al _0.3 Ga
A semiconductor quantum well structure in which 220 cycles of _0.7 As (80 angstrom per layer) are alternately laminated, 212 is p-type AlGaAs (thickness: 0.5 μm), and the above layer is 2
Films other than 01 were all formed by the molecular beam epitaxy method. Also,
Reference numerals 206a and 206b are AuGeNi ohmic electrodes, 207 is a load resistor, and 213 is a Cr / Au ohmic electrode. 206b and 213 of ohmic electrodes
Was grounded.

The write light P _in enters the heterojunction phototransistors 202 to 204 and the read light P _bias enters the optical modulators 211 and 212 in the EARS 13. At this time, the optical modulators 211 and 21 according to the writing light P _in
As the absorption of 2 changes, the reflected light P of the read light P _bias is changed.
_out is modulated and emitted. The optical modulator composed of 211 and 212 is in a light transmitting state when a voltage is not applied at a wavelength of 850 nm, and the transmittance decreases when a reverse bias voltage of 10 V or more is applied. Since the parallel structure of the heterojunction phototransistors 202 to 204 and the optical modulators 211 and 212 is connected in series with the load resistor 207 in the EARS 13, the absorption of the optical modulator can be controlled by the writing light P _in . When the writing light P _in is applied to the hetero-junction phototransistors 202 to 204, the amplified photocurrent flows through the transistors and the resistance is equivalently low, so that the optical modulators 211 and 212.
Almost no voltage is applied to the cell and the cell is in a transparent state. That is, the reflected light P _out is output from the EARS 13. on the other hand,
When the writing light P _in is not irradiated, no current flows in the heterojunction phototransistors 202 to 204, that is, a large reverse bias voltage is applied to the optical modulators 211 and 212 in a high resistance state, so that reflection occurs in a light absorbing state. Light P _out
Is hardly output from the EARS 13. In summary, in the EARS 13, if the writing light P _in is irradiated,
The reflected light P _out of the read light P _bias is output, and the reflected light P _out is not output unless the write light P _in is emitted.

Returning to FIG. 8, the operation of the image transmission apparatus of this embodiment will be described. In the second embodiment described above, the coherence in the PRC is controlled by the polarization direction, but in the third embodiment it is controlled by the presence or absence (strength) of light. This control is performed by EARS13.
And the heterojunction phototransistor 2 on the PRC 2d
02-204 are the optical modulators 211 and 2, facing the front of the drawing.
12 are arranged in the PRC 2d direction. EARS13
In the matrix, elements each having a diameter of 30 μm are arranged in a matrix of 32 rows and columns, and a total of 1024 bits are integrated. In FIG. 8, only four elements are drawn. 2 of them on the right
The writing light P _in is irradiated to each of the elements, and the left 2
The writing light is not applied to the individual elements. The wavelength of the writing light P _in is also 850 nm. Scattered light E21, E2
2 is totally reflected on the right side surface of the PRC 2d, the ray E21 is incident on the upper right optical modulator, and the ray E22 is incident on the upper left optical modulator. To show the state to the four optical modulators,
The left side is shown in black and the right side is shown in white according to the writing light pattern. The laser light having a wavelength of 850 nm for data transmission enters the PRC 2d as an incident light ray of E1. This ray is scattered as rays E21 and E22 at the point x. Of these rays, the ray of E22 is incident on the light modulator in the absorption state on the left side, and has no effect thereafter.
However, the ray E21 is reflected by the light modulator in the reflection state, then travels in the PRC 2d as a ray E31 ', and interferes with the original ray E1 at the point of y. Due to the refractive index distribution generated by the interference of the light rays of E1 and E31 ', new diffracted light E21' is produced at the point of y. Diffracted light E21 'is E21 and E3
It travels exactly in the opposite direction to the ray 1 ', and after reflection at the EARS 13, passes through points x and y as the ray E31 and exits from the PRC 2d as the ray E4. At this time, E
The ray of 4 carries a light pattern on the EARS 13 as in the first and second embodiments described above. That is, the image transmission apparatus of this embodiment can transmit two-dimensional data represented by an optical pattern in parallel in addition to the image signal in exactly the same manner.

[0028]

As described above, according to the present invention,
Image patterns and two-dimensional optical data can be efficiently transmitted directly in parallel as light, alignment is easy, there is no need to use an optical fiber with the same characteristics as before, and the transmitted light intensity is strong enough. Image pattern can be obtained. That is, according to the direct image transmission device of the present invention, since the time series processing of the image signal is not involved, the image pattern can be transmitted at high speed and with high resolution. Further, according to the present invention, in addition to image transmission, two-dimensional data transfer in a computer or an exchange can be executed at high speed.
As described above, the direct image transmission device of the present invention can be applied to a wide range of fields such as image transmission, optical interconnection, and high-speed data transfer.

[Brief description of drawings]

FIG. 1 is an optical path diagram showing a configuration example of a conventional direct image transmission device.

FIG. 2 is an optical path diagram showing a configuration of a direct image transmission device according to a first embodiment of the present invention.

FIG. 3 is an optical path diagram showing a configuration of a direct image transmission device according to a second embodiment of the present invention.

4 is a top view showing a structure of an SLM (spatial light modulator) 12 of FIG.

5 is a vertical cross-sectional view taken along the section line CC ′ of FIG.

6 is a perspective view showing a detailed optical path and a principle of operation in the vicinity of the PRC 2b and the SLM 12 of FIG.

FIG. 7 is an optical path diagram showing a configuration of a direct image transmission device according to a third embodiment of the present invention.

8 is a perspective view showing a detailed optical path near the PRC 2d and the EARS 13 in FIG. 7 and a principle of operation.

9 is a vertical sectional view showing a detailed structure (1 bit) of the EARS 13 of FIG.

[Explanation of symbols]

1a, 1b, 1c Laser light source 2a, 2b, 2c, 2d Photorefractive crystal (PRC) 3a-3k Lens 4 Frosted glass 5a, 5b Image pattern 6a, 6b, 6c Screen 7a, 7b, 7c, 7d Half mirror 9a, 9b Multi Mode Optical fiber 10 Halogen lamp 11 Pulse power supply 12 Spatial light modulator (SLM) 13 EARS (exciton absorption reflection switch) 14 Laser diode 15 Planar quartz waveguide 16 Control electrode 17 Surface emitting laser array 18 Photodetector array 23 Collimator 24 Concave mirror 25 Object 101a, 101b Quartz glass substrate 102 Ferroelectric liquid crystal layer 103a, 103b, 103c Transparent electrodes 104a, 104b Alignment film 105 Dielectric mirror 106 Conductive film 107 Silver paste 108 Sealing material 1 9a, 109b Lead electrode 110 Ceramic spacer 201 Element substrate 202 Phototransistor emitter layer 203 Phototransistor base layer 204 Phototransistor collector layer 206a, 206b Ohmic electrode 207 Load resistance 210 Distributed Bragg reflector 211, 212 Optical modulator 213 Ohmic electrode

Claims (2)

[Claims] 1. A photorefractive crystal for generating a phase conjugate wave by self-pumping, an optical modulator for writing an image signal in the photorefractive crystal and a transmission side optical system, a laser light source for driving the photorefractive crystal, An image comprising: a transmission medium that transmits the phase conjugate wave of the image signal generated from a photorefractive crystal; and a reception-side optical system that forms an image of the phase conjugate wave transmitted by the transmission medium. Transmission equipment. 2. The image transmission device according to claim 1, wherein the light modulator is one of a spatial light modulator, an exciton absorption / reflection switch, and a self-electro-optic effect device.