KR100245829B1 - Optical device - Google Patents

Abstract

The optical control device has a light transmitting medium that exhibits a low transmittance at a specific light wavelength λ ₁ and a high transmittance at a light wavelength λ ₂ of its attention, and a light generating element that generates light having a light wavelength λ 1 or λ ₂ , The light intensity transmitted through the light transmitting medium is controlled in accordance with the change of the control light.

In addition, the optical functional device has a hysteresis according to a light transmission medium having a low transmittance at a specific light wavelength λ 1 and a high transmittance at a light wavelength λ ₂ , λ ₃ (λ ₂ <λ 1 <λ ₃ ) of the attention, and a current injection amount or light irradiation amount. by the while changing the wavelength causing light wavelength λ1, λ _2, λ hayeoseo hold the light-generating element for generating a _third of the light, the light transmitted by the light intensity to the medium passing through the hysteresis in accordance with the wavelength change of the light-generating device low intensity or high intensity The memory function is realized by maintaining the state.

Description

Optical device

1 is a block diagram showing an example of an optical control device of the present invention and an apparatus for measuring its function.

2a, b, and c are block diagrams showing the injection current into the semiconductor laser element, the intensity of the output light of the semiconductor laser element, and the light intensity after transmission of the light transmitting medium, respectively.

3 is a correlation diagram of injection current and light transmittance into a semiconductor laser device.

4 is a correlation diagram of light intensity and injection current into a semiconductor laser device.

5 is a correlation diagram of oscillation wavelength and transmittance of a semiconductor laser device.

6 is a block diagram showing another example of the light control device of the present invention and its function measurement device.

7 is a correlation between laser intensity and transmittance.

8 is a block diagram illustrating an optical functional device of the present invention and an apparatus for measuring the function thereof.

9a, b, and c are correlation charts showing light intensity after injection current, output light, and light transmission medium into the semiconductor laser device, respectively.

10A and 10B show correlations between light wavelength and intensity when the injection current increases, respectively.

11A and 11B show correlations between light wavelength and intensity when the injection current decreases, respectively.

2 is a light absorption spectrum diagram of a light transmitting medium.

13A, 13B and 13C show the correlation between the injection current into the semiconductor laser device, the output light, and the light intensity after passing through the light transmitting medium.

14A and 14B show correlations of the intensity of light wavelength with increasing injection current, respectively.

15A and 15B show correlations of intensities of light wavelengths when the injection current decreases, respectively.

16 is an output waveform diagram of a short pulse.

17 is another output waveform diagram of the short pulse.

* Explanation of symbols for main parts of the drawings

10: light transmitting medium 11: semiconductor laser device

12: drive control circuit 13: temperature controller

14 beam splitter 15 condenser lens

16: photodetector 17: digital oscilloscope

18 optical power meter 19 spectrometer

20: automatic rotating ND filter 21: optical spectrometer

The present invention relates to an optical device, and more particularly, to an optical control device useful as an optical inverter which is indispensable for performing optical logic operations and light computing in the optoelectronic field, and an optical functional device useful as an optical memory. It is about.

In recent years, the progress of optoelectronic technology is remarkable, and its importance is becoming more and more important as a foundational technology that opens a new era of optical communication, optical computer and the like.

In such a situation, as one of the control techniques for using light, an optical control method for performing a logical operation of a computer by an optical signal has been studied.

For example, in the optoelectronic field such as optical communication and optical information processing, research has been conducted to control the controlled light by the control light. According to this method, the switching operation can be performed faster than the electrical switching circuit, and multiple parallel processing can be performed by using the imaging of light, and its usefulness is expected in an optical integrated circuit or the like.

On the other hand, optical devices using nonlinear optical effects have been actively studied for light control. In the nonlinear optical effect, the wavelength conversion effect such as the generation of second harmonic has been considered as practical in the past, but recently, the effects of the change of the writing rate and the absorption coefficient depending on the intensity of light have been focused and studied. Physics 59, pages 155-163, issued February 1990). However, the effect of changing the refractive index and the absorption coefficient due to the light intensity is caused by the third order polarization, so a nonlinear optical material having a high degree of polarization effect is required ["Degenerate fourwave mixing in semiconductor- doped glasses". "J. Opt. Soc. Am. , 73, pp. 647-653 (May 1983)]. In the absorption saturation type bistable semiconductor laser, which is most promising as a semiconductor light control element, an optical input is used for a switch that switches from an off state to an on state, but on the contrary, an optical state is switched from an on state to an off state (NOT circuit). Since there is no negative light pulse in the field, it is a fact that it is not realized (Application Physics 58, pages 1574 to 1583: issued in November 1989). Optical bistability as used herein means a phenomenon in which the output intensity takes two stable states with respect to one light intensity.

On the other hand, an optical memory for storing optical signal information is also indispensable. The optical memory refers to a memory that uses light for both recording and reading of information, but broadly includes light which is used for either of them. For such an optical memory, its importance is recognized, but unfortunately, what is currently put into practical use is analog image memory, and many others are in the research stage.

Among the promising ones, there are holographic memory, photomagnetic memory, and glass semiconductor memory. The holographic memory is a photograph of optical interference obtained by laser light. However, this memory has a drawback that reading and developing are necessary at high speeds.

The magneto-optical memory records information by irradiating a laser beam to a ferromagnetic material such as MnBi, and reads the information by using a Faraday effect that causes polarization of transmitted light according to the magnetization state. Memory, but the combination of light and magnetism is a drawback.

The glass semiconductor memory irradiates light of moderate intensity to the glass semiconductor, thereby reversibly phase shifting between the polycrystal and the amorphous and using a shape in which the transmittance changes. The memory which reads out has a drawback such as a slow switching speed of the phase transition. On the other hand, although studies have been made to configure an optical memory using a double-safe semiconductor laser, the same problems as described above have been realized and are not realized.

In general, it is known that a gentle vibration occurs in the oscillation light intensity when a high-speed pulse operation of a semiconductor laser is performed. This relaxation vibration phenomenon is observed in most kinds of lasers in addition to semiconductor lasers. The basic physical mechanism of this phenomenon is a correlation between the vibration electromagnetic field and the inversion distribution of atoms in the resonator. Increasing the strength of the intestine leads to a decrease in the inversion distribution density through an increase in the induced emission rate. It also leads to a decrease in gain, which in turn leads to a decrease in field strength.

Therefore, the semiconductor laser rises instantaneously due to the rapid rise of the driving current, but after that, the light intensity fluctuates by about 1 nsec. For this reason, the pulse response speed is suppressed at the maximum of about 1 nsec, and the method of controlling the damping vibration is examined.

For example, the external light injection method is a method of injecting the oscillation light of another laser that operates in conjunction with a semiconductor laser which directly modulates, and can suppress the relaxation vibration (R. Lang K. Kobayashi). : Suppression of the relaxation oscillation in the modulated output of semiconductor lasers, IEEE J. Quantum Electron., QE-12, 3, PP194-199 (1976). However, in this case, there is a drawback that two lasers are required and the oscillation shaft modes must be matched.

It is an object of the present invention to provide an indispensable square value for performing photological operation and optical computing in the photoelectronic field.

More specifically, the present invention provides an optical control apparatus for switching an optical signal from an on state to an off state, that is, to realize an optical NOT circuit and to enable an all-optical logic operation. It is aimed.

Another object of the present invention is to provide an optical functional device that stores information of an optical signal by electric input or optical input.

The present invention comprises a light transmitting medium that exhibits a low transmittance at a specific light wavelength λ ₁ and a high transmittance at a light wavelength λ ₂ around it, and a light generating element that generates light having a light wavelength λ 1 or λ ₂ , and has a light wavelength from the light generating element. λ1 is irradiated on the light-transmitting medium or the electrical control of the light λ _2, there is provided a light control device for controlling the light intensity passing through the light transmission medium in accordance with the control pulse changes.

In this light control device, the light generating element generates light of either one of the light wavelength lambda 1 or lambda ₂ by a control input applied electrically or optically from the outside. This controlled light controls the transmittance of the light transmitting medium. As a means for this, in the present invention, the optical properties of the light transmitting medium are controlled, and for example, a specific element such as a rare earth element is contained in a suitable material such as a transparent ceramic, glass, semiconductor, insulator or the like. The optical transition of rare earth elements is an inner shell transition, which is difficult to be affected by the base metal. By incorporating the rare earth element into the optical transmission medium as a doping element, the ground absorption from the base level E1 to the excitation level E ₃ for the light of λ1 and the excitation level from the metastable level E ₂ to to E ₄ can be generated here for absorption _{(excited absorption) (E 4>} E 2> E 3> E1). for this reason, the transmittance at the light wavelength λ1 significantly reduced.

On the other hand, the light-generating element, as electric, electronic, or when the optically controlled from the outside, generate a wavelength is changed from λ1 to λ _2, or from ₂ to λ λ1. For example, when a semiconductor laser is used as a light generating device, it is generally known that the oscillation wavelength discontinuously changes toward the longer wavelength as the current injection amount increases (M. Nakamura, "Single mode operation of semiconductor injection lasers" IEEE). Trons, Circuits and systems, Cas-26, 1055 (1979). Assuming that the oscillation wavelength has changed from λ ₂ to λ 1 when the injection current into the semiconductor laser is increased, the light intensity of λ ₁ is higher than the light intensity of λ ₂ . However, when the output of the semiconductor laser is incident on the above light transmitting medium, the light wavelength? 1 is lower than? ₂ , so the light output is smaller than? ₂ , so that the optical NOT circuit is realized.

As described above, in the present invention, the light transmitting medium exhibits low transmittance and high transmittance with respect to the light wavelengths λ 1 and λ ₂ , respectively. Therefore, when light having a light wavelength λ 1 is input to the light transmitting medium, the hole is absorbed and turned off. When light having a light wavelength of λ ₂ is input, it is transmitted and turned on. In addition, as described above, the element generating excitation absorption can be doped with respect to light having a wavelength of λ ₂ , so that an excitation absorption having a greater absorption degree than the base absorption occurs, and the light transmitting medium is associated with this excitation absorption. The transmittance of [lambda] 1 penetrating is significantly reduced. The difference between the light transmittances of [lambda] 1 and [lambda] ₂ penetrating the light transmitting medium becomes significant, so that on. The optical inverter (NOT circuit) with a large off ratio is enabled. An optical inverter (NOT circuit) is enabled, and all the logic circuits (for example, NOR, XOR, etc.) can be configured by combining the inverters. Therefore, optical logic operation and an optical computer can be realized using the optical control device of the present invention as a main device.

In addition, the present invention relates to a light transmission medium exhibiting a low transmittance at a specific light wavelength λ ₁ , and a high transmittance at a light wavelength λ ₂ and λ ₃ (λ ₂ <λ ₁ <λ ₃ ) around it, and a current injection amount or light irradiation amount. Therefore, it is composed of a light generating element that generates light of wavelengths λ ₁ , λ ₂ , λ _{3 by} changing the wavelength while causing hysteresis, and transmits light of light wavelengths λ ₁ , λ ₂ , λ ₃ from the light generating element It is also possible to provide an optical functional device that emits light, and maintains the light intensity transmitted through the light transmitting medium in a low intensity or high intensity state by hysteresis of wavelength change, thereby expressing a memory function.

In this optical functional device, the photo-generator generates one of the light wavelengths [lambda] ₁ , [lambda] ₂ or [lambda] ₃ by applying a control input electrically or optically from the outside. By this controlled light, the transmittance of the light transmitting medium is controlled, and since the wavelength change retains hysteresis with respect to the control input, the light intensity transmitted through the light transmitting medium is kept in a low intensity or high intensity state, so that the memory function is maintained. Is realized.

As a means for this purpose, in the present invention, as in the case of the light control apparatus described above, the optical properties of the light transmitting medium are controlled, for example, suitable for transparency ceramics, glass, semiconductors, insulators, etc. For example, rare earth elements are contained. As a result, the light transmission medium exhibits a low transmittance for the light wavelength λ ₁ and a high transmittance for the light wavelengths λ ₂ and λ ₃ . When light having a light wavelength λ ₁ is input to the light transmitting medium, the light is absorbed and turned off. When light having light wavelengths λ ₂ and λ ₃ is input, it is transmitted and turned on. In addition, since the wavelength change from λ ₂ to λ ₁ and λ ₁ to λ ₃ retains hysteresis with respect to the control input, the off state and the on state are preserved.

On the other hand, when the photo-generating element is electrically or optically controlled input from the outside, the photo-generating wavelength changes from λ ₂ to λ _λ or from λ _λ to λ ₃ . For example, in the case of using a semiconductor laser as a light generating device, it is generally known that when the injection amount is decreased from high current injection, the oscillation wavelength is discontinuously changed toward the short wavelength with hysteresis (M. Nakamura, "Single mode operation). of semiconductor injection lasers "IEEE Trons. Circuits and systems, CAS-26, 1055 (1979)). When the current is increased in the semiconductor laser from the low injection state to the high injection state, the oscillation wavelength is changed from λ ₂ to λ ₁ , and returned to the low injection state, the oscillation wavelength retains hysteresis with respect to the injection current. Even when returning to the injection state, the oscillation wavelength of λ ₁ is preserved to maintain a low transmittance state (that is, off state). In addition, when the low injection state and the high occurrence of each of the oscillation wavelength λ _1, λ ₃ to the injection state also by the same principle, and the transmittance state by re-holding preserving oscillation wavelength of λ ₃ even when return to a low injection state (i.e., on). This realizes the memory function.

By using this memory function, the effect of the relaxation vibration which causes the deterioration of the pulse drive switching speed of the semiconductor laser can be eliminated, and the high speed switching operation is made possible. For example, when the current of the semiconductor laser at a high injection state from 0 or a low injection state changes the oscillation wavelength to λ _1, then some current injection amount change (relaxation oscillations) in Fig., The oscillation wavelength of λ ₁ by the hysteresis effect Keep it. For this reason, even when lightening vibrations are generated intensely, when the above-mentioned permeation medium is transmitted, the change in intensity due to the lightening vibrations can be eliminated. Since the switching time of the optical functional device is limited only by the rise time of the semiconductor laser, the high speed switching operation is realized.

In the optical functional device of the present invention, a light transmitting medium can be provided, for example, in a resonator of a semiconductor laser light generating element. In this case, since the laser light is repeatedly reflected in the resonator and absorbed by the light transmitting medium each time, the effective date of the light transmitting medium can be lengthened, and the light transmitting medium can be thinned, so that the optical functional device can be thinned. Miniaturization can be achieved. In addition, the optical functional device can be connected in multiple stages, and as one of the methods, it is possible to enumerate a light receiving element such as a phototransistor in parallel with the optical functional element. In this way, the optical signal from the front end can be received by the light receiving element, and its output current can be used as the injection current of the light generating element, thereby enabling multi-stage connection.

In this way, the optical memory is enabled by the optical functional device. This optical memory can be configured with any type of memory of the switch off type (low light intensity state) and the switch on type (high light intensity state) with respect to the control input in accordance with the optical wavelength selection method. Moreover, at the time of switching of this optical function device, high speed operation | movement without the influence of a damping vibration is possible.

The optical printing device and the optical functional device of the present invention are optical logic devices by red-shift of diode laser and inverter of optical nonlinear absorption by red-shift of inverter and semiconductor laser using optical nonlinear absorption. : ORION).

EMBODIMENT OF THE INVENTION Hereinafter, the light control apparatus and optical function apparatus of this invention are demonstrated in detail based on drawing.

Example 1

In FIG. 1, as the light transmitting medium 10, a rod having a diameter of 3 mm x 3 mm made of yttrium-aluminum garnet (YAG) containing erbium (Er ³⁺ ) is used. Er concentration is 50at. It was set as%.

The semiconductor laser element 11 functioning as a light generating element is driven by the drive control circuit 12 and the temperature controller 13 to output a laser beam of a constant wavelength, and a beam splitter 14 and a light condenser are collected. The lens 15 was incident on the light transmitting medium 10 made of Er: YAG.

The light output transmitted through the light transmitting medium 10 was received by the light detecting element 16 and observed with a digital oscilloscope 17 and a light power meter 18. The results are shown in FIGS. 2 and 3.

Comparing FIG. 2B and FIG. 2C, the light intensities B and C of the output of the semiconductor laser element 1λ shown in FIG. 2B are inverted after transmission of the light transmitting medium 10 as shown in FIG. 2C. It can be seen that. This phenomenon is also confirmed by FIG. It can be seen that the transmittance is reduced by about one third at point D in FIG.

In addition, the wavelength change of the laser output with respect to the injection current of the semiconductor laser element 11 was measured using the spectroscope 19 shown in FIG. The results are shown in FIG.

The black ring in FIG. 4 shows the light detection intensity when the wavelength of the spectrum 19 is set to 787 nm, and the white ring shows the light detection intensity when the wavelength is set to 784.5 nm. At the point E of 73 (73 mA), the light intensity of 784. 5 nm decreased, and conversely, the light intensity of 787 nm was observed to increase rapidly. As a result of increasing the injection current into the semiconductor laser element 11, it shows that the central oscillation wavelength was discontinuously changed from 784.5 nm to 787 nm at point E. In this discontinuous E, the injection current value coincided with the injection current value at point D in FIG. In addition, as can be seen from the 5 degrees, and the light transmitting medium (λ0) peak at 787nm is absorbed, this Er: corresponding to the Er ³⁺ in YAG excitation absorption _{^{(2 H 11 / 2- 4 I}} 13/2) , and there was.

As apparent from the above results, the phenomenon shown in FIG. 2 in which the light output is inverted by transmitting the Er: YAG light transmitting medium 10 is easily understood.

Example 2

In FIG. 6, Er: YAG used a rod of φ3 mm × 25 mm as the light transmitting medium 10. In FIG. Er concentration is 16at. It was set as%.

The semiconductor laser element 11 functioning as a light generating element is driven by the drive control circuit 12 to output laser light having a center wavelength of 787 nm, and through the beam splitter 14 and the condenser lens 15, Er: It entered into the YAG light transmitting medium 10. This laser light was received by the photodetector element 16, and the light intensity was measured by the optical power meter 18 to calculate the transmittance. The result is shown in FIG.

In addition, the injection current into the semiconductor laser element 11 was made constant at 99 mA, and the laser light intensity was changed using the automatic rotation ND (neutral density) filter 20.

From Fig. 7, it was found that the transmittance at point B is about twice the transmittance at points A and C.

Therefore, the high transmittance state (optical switch on) is obtained by setting the intensity of the B point from the laser light intensity of the A point, and the low transmittance state (optical switch is off) by setting the intensity of the C point from the laser light intensity of the B point. ) Is confirmed.

In addition, it is confirmed that the effect of decreasing the transmittance (point B to point C) with respect to the increase in the light intensity improves the on / off ratio of the inverter shown in the first embodiment.

Example 3

In FIG. 8, as the light transmitting medium 10, a rod having a diameter of 3 mm x 3 mm made of yttrium-aluminum-ganet (YAG) containing edbium (Er ³⁺ ) was used. Er concentration is 50at. %. That is, it was set as (Er _0.5 Y _0.5 ) ₃ A1 ₅ O ₁₂ as a composition.

The semiconductor laser element 11 functioning as a light generating element is driven by the drive control circuit 12 and the temperature controller 13 to output laser light of a constant wavelength, and to Er: YAG through the beam splitter 14. It entered the light transmission medium 10 which consists of.

The light output transmitted through the light transmitting medium 10 was received by the photodetecting device 16 and observed with a digital oscilloscope 17 and an optical spectroanalyzer 21.

9 shows the result. In addition, the temperature controller 13 was adjusted to keep the laser head temperature at 33 deg. Comparing FIG. 9B and FIG. 9C, the light intensity change of the output of the semiconductor laser element 11 shown in FIG. 9B is inverted (low light intensity state) after transmission of the light transmitting medium 10, and the low light intensity state. It can be seen from FIG. 9C that the memory function for maintaining is completed.

This phenomenon is also confirmed by FIG. 10 and FIG. FIG. 10A shows the relationship between the light wavelength and intensity detected by the optical spectrometer 21 when the current injected into the semiconductor laser element 11 is increased from 54 mA to 5 mA by 99 mA. 10B is a detection result of the optical spectrometer 21 after transmission of the light transmitting medium 10. 11A shows the relationship between the light wavelength detected by the optical spectrometer 21 and the intensity when the current injected into the semiconductor laser element 11 is reduced from 99 mA to 54 mA by 3 mA. 11B is a detection result after having passed through the light transmitting medium 10.

It is found from FIG. 10A that the light wavelength is discontinuously changed from 786. 1 nm to 787. 5 nm at 78 mA as the injection current is increased. 11A, it can be seen that the optical wavelength is discontinuously changed from 787. 5 nm to 786. 1 nm when the injection current is reduced to 60 mA. It is confirmed from these 10a and 11a that there is hysteresis with respect to the injection current in the optical wavelength change.

It is also found that after passing through the light transmitting medium 10 from FIGS. 10B and 11B, light of 77.5 nm is absorbed by the light transmitting medium 10.

In FIGS. 10b and 11b, when the injection current of 75 mA is compared, respectively, the strong light intensity is observed in FIG. 10 (b), but the light intensity is almost zero in FIG. 11b. .

Therefore, as shown in FIG. 9A, the injection current (at low carrier injection) and 99 mA (at high carrier injection) are controlled and input to the semiconductor laser element 11, and the light output (Fig. 9b). ) Is irradiated to the light transmitting medium 10 and the transmitted light is observed to confirm that the light intensity output having the memory function as shown in FIG. 9C is obtained.

As described above, since hysteresis exists in the change of the optical wavelength with respect to the injection current, when the high carrier injection is changed from the low carrier injection condition and the optical wavelength is changed, the optical wavelength maintains the high carrier injection state even when the light carrier is returned to the low carrier injection state. By passing through the light transmitting medium, a memory function of preserving and maintaining a low intensity state is realized.

12 is the light absorption spectrum of Er: YAG described above. And a first 12 degrees 787. 3nm the absorption peaks in, this Er: and corresponding to the Er ³⁺ in YAG excitation absorption _{^{(2 H 11 / 2- 4 I}} 13/2).

Example 4

Using the same semiconductor laser device as Example 3, the temperature of the laser head was kept constant at 43 占 폚, and oscillation wavelengths of 787. 5 nm and 789. 6 nm were observed at the injection currents of 75 mA and 99 mA, respectively.

As is also apparent from the contrast between FIG. 13B and FIG. 13C, it can be seen that the light intensity functions as a memory for maintaining a high light intensity state.

14 and 15 show measurement results by the optical spectrometer 21 shown in FIG. 8, respectively.

FIG. 14A is a result of increasing the injection current from 54mA to 99mA by 3mA, and FIG. 14B is a result after passing through the light transmitting medium 10. FIG. On the other hand, Figure 15a is a result of reducing the injection current from 99mA to 54mA by 3mA, Figure 15b is the result after passing through the light transmission medium (10).

It can be seen from FIG. 14A that the light wavelength is discontinuously changed from 787. 5 nm to 789.6 nm at an injection current of 81 mA. In addition, from Fig. 15A, when the injection current is decreased, it is found that the optical wavelength is discontinuously changed at 69 mA. From these 14a and 15a, it is found that there is hysteresis with respect to the injection current in the optical wavelength change.

The laser light after passing through the light transmitting medium 10 from FIGS. 14B and 15B shows that light having an optical wavelength of 77.5 nm is absorbed by the light transmitting medium, and light of 789. 6 nm is transmitted. .

Therefore, as shown in Fig. 13A, a control input of an injection current of 75 mA (when low carrier injection) and 99 mA (when high carrier injection) is input to the semiconductor laser element 11, and the light output (Fig. 13b) is inputted. When the light transmitting medium 10 is irradiated and the transmitted light is observed, it is confirmed that a memory function of preserving and maintaining a high intensity state as shown in Fig. 13C is obtained.

As apparent from the above results, the memory function of maintaining low light intensity and high light intensity states is easily realized by allowing the light output to transmit the Er: YAG light transmitting medium.

Example 5

A in FIG. 16 is an input waveform when the oscillation wavelength is set to about 787. 5 nm for an injection current of 99 mA and a short pulse of 99 mA is formed. Laser-specific relaxation vibrations have been observed. B in FIG. 16 is an optical wavelength after transmission of the Er: YAG light transmitting medium. It should be noted here that the second and subsequent peaks of the relaxation vibration are suppressed in FIG.

This is, at the first rising oscillation wavelength is maintained to preserve the light wavelength of λ ₁ by the hysteresis effect in intensity changed by, relaxation oscillation reaches a predetermined light wavelength, e.g., λ ₁ (787. 5nm), an optical transmission medium When transmitted, it means absorbed. The damping vibration is suppressed, and high-speed operation is possible with a switching time of approximately rise time only. In this example, the switching time was about 100 ps.

For reference, the short pulse input waveform of 99 mA when the temperature of the laser head is adjusted to an optical wavelength of 786 nm (not λ ₁ ) and the output waveform after passing through the optical transmission medium are shown in FIG. Respectively. From B of FIG. 17, it is confirmed that most of the input light of A is transmitted as it is, and the influence of the relaxation vibration is exhibited.

In the above examples, Er ³⁺ is used as the rare earth element contained in the light transmitting medium, but the present invention is not limited thereto. It can select suitably according to the wavelength of light, the kind of light transmission medium, etc. Moreover, a suitable kind of light generating element can also be used.

Claims (23)

Be up a low transmittance at a specific light wavelength λ _1, a light-transmitting medium and a light-generating element that generates light at a light wavelength λ ₁ or λ ₂ showing a high transmittance in the optical wavelength λ ₂ therearound, the light wavelength from the light generating element λ ₁ Or a light transmitting medium irradiating the control light of λ ₂ to the electric light transmitting medium, and controlling the light intensity passing through the light transmitting medium according to the change of the control light. The light control device according to claim λ, wherein the light transmitting medium contains at least one rare earth element in one material selected from the group consisting of transparent ceramics, glass, semiconductors, and insulators. The light control device according to claim 2, wherein at least one rare earth element is erbium Er ³⁺ . 4. The light control device according to claim 3, wherein the light transmitting medium contains erbium Er ³⁺ , which is a rare earth element, in transparent ceramic YAG (yttrium-aluminum-garnet). The method of claim 3, wherein the light control device made in the low-transmittance optical wavelength λ ₁ of the light transmission medium in the vicinity of the erbium heumsu peak excitation absorption of _{^{Er 3+ (2 H 11 / 2-}} 4 I λ3 / 2). Light control device formed by a vicinity of the absorption peak of claim 4, wherein in, the low-transmittance optical wavelength λ ₁ of the light-transmitting medium byum Ed Er ³⁺ of excitation ^{_{(2 H 11 / 2- 4 I}} 13/2) to. The light generating element according to claim 1, wherein the light generating element is a semiconductor laser (11), which generates light having a wavelength of λ ₂ and λ ₁ at low current injection and high current injection, or at the time of current injection and high current injection, respectively. Optical control devices for generating light having a wavelength of λ ₁ and λ ₂ , respectively. 8. The light control device according to claim 7, wherein the light generating element is an absorption saturation semiconductor laser. It consists of a light transmitting medium that shows low and high transmittance for a specific light intensity, and a light generating device that generates light of only the light wavelength λ _λ , and irradiates the light transmitting medium with the light having a wavelength of λ ₁ from the light generating device. And a light control device for controlling the light intensity passing through the light transmitting medium by increasing or decreasing the light intensity. At a specific light wavelength λ _λ , the light transmittance exhibits low transmittance, and at the surrounding light wavelengths λ ₂ and λ ₃ (λ ₂ <λ ₁ <λ ₃ ), a light transmitting medium exhibiting high transmittance and hysteresis are generated according to the amount of current injection or light irradiation. hayeoseo change, light wavelength λ _1, λ _2, λ ₃ which consists of a light generating device for generating light, a light irradiating the optical wavelength of light λ _1, λ _2, λ ₃ from the light generating element and transmitted through the light transmission medium An optical functional device that preserves the intensity in a low intensity or high intensity state in accordance with the hysteresis of the wavelength change, thereby expressing a memory function. 11. The light emitting device according to claim 10, wherein the light generating element is a semiconductor laser, and the semiconductor laser can inject carriers into the active region by current or light irradiation, and at λ ₂ , which is an optical wavelength from low carrier injection to high carrier injection. When λ ₁ is changed and the carrier is injected again, hysteresis preserves the light wavelength of λ ₁ and maintains the light intensity transmitted through the light transmission medium in a low intensity state, and from high carrier injection to high carrier. When injected, the optical wavelength changes from λ ₁ to λ ₃ , and when it returns to low carrier injection, the optical function preserves the λ ₃ wavelength by hysteresis and maintains the light intensity transmitted through the air-transmitting medium at high intensity. Device. The optical functional device according to claim 10, wherein the light transmitting medium contains at least one rare earth element in one material selected from the group consisting of transparent ceramics, glass, semiconductors, and insulators. The optical functional device according to claim 11, wherein the light transmitting medium contains at least one rare earth element in one material selected from the group consisting of transparent ceramics, glass, semiconductors, and insulators. 13. The optical functional device of claim 12, wherein the at least one rare earth element is erbium Er ³⁺ . The optical functional device according to claim 13, wherein at least one rare earth element is erbium Er ³⁺ . 15. The optical functional device according to claim 14, wherein the light transmitting medium contains erbium Er ³⁺ , which is a rare earth element, in YAG (yttrium-aluminum garnet), which is a transparent ceramic. 16. The optical functional device according to claim 15, wherein the light transmitting medium contains erbium Er ³⁺ , which is a rare earth element, in transparent ceramic YAG (yttrium-aluminum-garnet). The method of claim 14, wherein the light function unit formed by the absorption peaks in the vicinity of the low-transmittance optical wavelength λ ₁ of the light-transmitting medium erbium Er ³⁺ of excitation ^{_{(2 H 11 / 2- 4 I}} 13/2). Light function unit formed by the absorption peaks in the vicinity of claim 15 wherein the low transmittance of light wavelength λ ₁ erbium Er ³⁺ of excitation ^{_{(2 H 11 / 2- 4 I}} 13/2) of the light transmitting medium. The method of claim 16, wherein the light function unit formed by the absorption peaks in the vicinity of the low-transmittance optical wavelength λ ₁ of the light-transmitting medium erbium Er ³⁺ of excitation ^{_{(2 H 11 / 2- 4 I}} 13/2). The method of claim 17, wherein the light function unit formed by the absorption peaks in the vicinity of the low-transmittance optical wavelength λ ₁ of the light-transmitting medium erbium Er ³⁺ of excitation ^{_{(2 H 11 / 2- 4 I}} 13/2). The optical function device according to claim 10, wherein the optical intensity device operates at a high speed by suppressing fluctuations in light intensity due to relaxation vibrations generated during laser oscillation. The optical function device according to claim 10, wherein the light transmitting medium is provided in a resonator of the semiconductor laser light generating element, and the light receiving element is provided in parallel to reduce the size and multistage connection.