JPS5941170B2 - thin film light switch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thin film optical switch used in optical communication systems and optical information processing systems.

15 As shown in FIGS. 1 and 2, a conventional thin film switch includes a thin film 2 made of, for example, glass or zinc oxide that can propagate light on a substrate 1 whose refractive index changes when an electric field is applied. The light L is applied to the thin film 2 through the prism 3, and this light is transmitted to the thin film 2.
The light is reflected and propagated between the interface between this and the substrate 1 and the interface between the thin film 2 and the medium on the upper surface side, and then is emitted to the outside via the prism 4. Let the emitted light υ reach the external optical circuit 6 through the slit 5 25
On the other hand, electrodes T and 8 are respectively attached on the opposite surfaces of the substrate 1, and leads 9 and 10 are formed between them.
A configuration has been proposed in which a required voltage is applied from a power source (not shown) via a power source to apply an electric field to the substrate 1, thereby changing the refractive index of the substrate 1.

According to such a configuration, the refractive index of the substrate 1 changes depending on whether an electric field is applied to the substrate 1 or not, or as the strength of the electric field changes when an electric field is applied. The reflection angle θ of the light f reflected and propagated within the slit 2 changes, thereby obtaining the state of whether or not the light passes through the slit 5. Thus, the external optical circuit 6
Looking at the thin film 2 side from the side, the optical switch function is obtained.As is clear from the above, electrodes 7 and 8 are attached to the substrate 1, and leads 9 and 10 are connected to these electrodes 7 and 8, respectively. It has the disadvantage that it requires troublesome work.

However, this was even more so if we tried to downsize the entire device. In addition, a power source is required to apply an electric field to the substrate 1, and if the refractive index of the substrate 1 is to be greatly changed to obtain an efficient switch function, a power source having a large capacity for applying an electric field to the substrate 1 is required. or the spacing between the electrodes 7 and 8 may be small, and if the electrodes 7 and 8 are made small, the shape of the substrate 1 and the thin film 2 applied on this substrate 1 will change accordingly. It also had drawbacks, such as the shape of the material being limited. The present invention therefore seeks to propose a novel thin film switch which does not have the above-mentioned drawbacks, as will become clearer from the following detailed description of embodiments of the invention with reference to the drawings.

FIG. 3 shows a first embodiment of the present invention, and FIG.
Although parts corresponding to those in the figure are shown with the same reference numerals, they do not absorb light like glass. A thin film 12 capable of propagating light containing .
The light L to be propagated through the thin film 12 is made incident, and this light is reflected between the interface between this and the substrate 11 and the interface between this thin film 12 and the medium on the upper surface side. The light L5 is transmitted through the prism 4 to the outside, and the emitted light L5 is made to reach the external optical circuit 6 through the slit 5, while the thin film 12 allows the light M from the light irradiation device 13 to be transmitted to the outside. It has a structure that allows it to be irradiated with light.

The above is the first embodiment of the present invention. According to this configuration, the thin film 12 contains azobenzene, and the azobenzene is irradiated with light having a wavelength of around 320 mμ. If it is irradiated with light having a wavelength of around 440 mμ, it isomerizes to a structure with a cis structure, and if it is irradiated with light having a wavelength around 440 mμ, it isomerizes into a structure with a trans structure. The refractive index of the thin film 12 changes depending on whether the light M from the light irradiation device 13 is obtained, for example, as light having a wavelength of around 320 mμ or as light having a wavelength of around 440 mμ.

Incidentally, the fact that such a change in the refractive index of the thin film 12 can be obtained is as follows.
As a result of measuring the relationship between the thickness D (mμ) of the thin film 12 and the reflection angle θ of the light reflected and propagated within the thin film 12, it was found that the thin film 12 is irradiated with light having a wavelength of around 330 mμ. Therefore, when the azobenzene contained in the thin film 12 is isomerized to a cis-structure structure, the reflection angle θ increases as the film thickness D increases, as shown by the curve S in FIG. 4. Therefore, when the thin film 12 is irradiated with light having a wavelength of around 440 mμ, and the azobenzene contained in the thin film 12 is isomerized into a trans-structure structure, as shown by the curve T in FIG. Similarly, as the film thickness D increases, the reflection angle θ increases, but this is also clear from the results obtained with values different from those in the former case.

However, the measurement results shown in FIG. 4 are for the case where the refractive index of the substrate 11 is 1.580, the wavelength of the light propagated to the thin film 12 is 6328λ, and the mode is TEO. The refractive index is 1.588 when the azobenzene contained in the thin film 12 is isomerized into a cis structure, and 1.590 when it is isomerized into a trans structure. This is what I used to do. Therefore, according to the first embodiment of the present invention, the substrate 1
1 and thin film 12 are used as the substrate and thin film whose refractive index was determined to obtain the measurement results shown in FIG. If the thickness D of the thin film 12 is, for example, 1.4 μm, the reflection angle θ of the light beam reflected and propagated within the thin film 12 is 84.69 from 84.69. ．．
99 or vice versa, thereby obtaining the state of whether or not light passes through the slit 5, thus providing an optical switch function when looking at the thin film 2 side from the external optical circuit 6 side. It is something.

According to the embodiment of the present invention described above, an optical switch function can be obtained by changing the refractive index of the thin film 12 in response to the irradiation of the thin film 12 with light having a predetermined wavelength.

In this case, there is no need to attach electrodes to the substrate or connect leads to these electrodes as in the case of Figs. Since it is not necessary, it does not have any of the drawbacks described above in FIGS. 1 and 2. Further, the light switch function is performed in response to light irradiation to the thin film 12, and therefore, the light switch function is performed without electrical control, so that the light switch function can be easily obtained as a whole. It has the following great characteristics. Next, the fifth
Embodiment 2 of the present invention will be described with reference to the drawings. In this example, corresponding parts to those in FIG.
A thin film 14 capable of transmitting light, such as glass or zinc oxide, is attached to a substrate 11 similar to that shown in the figure;
A thin film 12 containing azobenzene similar to that shown in FIG.
4, the interface between this and the substrate 11 and this thin film 14
The light L'' is reflected and propagated between the interface formed by the and thin film 12, and is then emitted to the outside through the prism 4, and the emitted light L'' is made to reach the external optical circuit 6 through the slit 5. The structure is such that the thin film 12 is irradiated with light M from a light irradiation device 13 as in the case of FIG.

The above is the second embodiment of the present invention, but since this configuration is clear from the description of the first embodiment of the present invention shown in FIG. 3, detailed explanation thereof will be omitted. However, since the refractive index of the thin film 12 changes by irradiating the thin film 12 containing azobenzene with light having a predetermined wavelength, the reflection angle θ of the light f that is reflected and propagated within the thin film 14 changes. However, as a result, the state of whether or not light passes through the slit 5 can be obtained, and thus the optical switch function can be obtained, and in this case, the same excellent characteristics as in the case of Fig. 3 can be obtained. It is.

Next, referring to FIG. 6, a third embodiment of the present invention will be described. In this example, parts corresponding to those in FIG. In the above-described configuration, the light M from the light irradiation device 13 can be obtained, for example, in a triangular prism shape as shown in FIG. 7A or in a so-called lens shape as shown in FIG. 7B. The case of FIG. 3 is the same except that a mask 15 shown by dotted lines is provided in the irradiation device 13 so that the thin film 12 is locally irradiated with the light M having such a pattern. It has a similar configuration.

The above is the third embodiment of the present invention. According to this configuration, this embodiment will also be clear from the description of the first embodiment of the present invention in FIG. 3, so detailed explanation will be omitted. Although this is omitted, the thin film 12 containing azobenzene is
By being locally irradiated with light M from 3, the refractive index of the thus irradiated position 16 of the thin film 12 is obtained to be different from that of the other positions, so that the pattern of the light M is as shown in FIG. When the prism shape is shown in A, the so-called thin film prism is formed at the position 16 where the light M is irradiated, and when it is lens shaped as shown in FIG. 7B, the so-called thin film lens is formed at the position 16. It is something that exists.

Therefore, according to the third embodiment of the present invention, the light is refracted and propagated by such a thin film prism or thin film lens, and the same switch function as in the case of FIG. 3 is obtained. It is. Next, other embodiments of the present invention will be described.
In the first to third embodiments described above, the thickness D of the thin film 12 is selected to be within the range where curves S and T in FIG. 4 are obtained. , in Fig. 4, the curves T and S differ from each other in terms of the value of the thickness D.
As is clear from the parts not shown extending below and b, if the thickness of the thin film 12 is below a certain value, the light propagating within the thin film 12 cannot be obtained as effective emitted light. It is something that will disappear. Therefore, although not shown, the first to third
In the configuration of the embodiment, the slit 5 is omitted, but the thickness D of the thin film 12 is reduced by the thickness of the substrate 11, the thin film 12, and the light L.
is the same as in the first to third embodiments described above, the same as in the first to third embodiments except that the intermediate value C between a and b in FIG. 4 is selected. Then, the light illumination device 1
If the light M from 3 has a wavelength near 320 mμ as described above, the light emitted from the thin film 12 cannot be obtained. C is obtained, and therefore the external optical circuit 6
When looking at the thin film 12 side from the side, an optical switch function is obtained, and in this case, in addition to the features described in the first to third embodiments, there is a great feature that there is no need to provide the slit 5. It is something. In the above description, only a few embodiments of the present invention have been shown, and a detailed explanation thereof will be omitted. However, as shown in FIG. 8, a thin film similar to the thin film 14 shown in FIG. A plurality of n pieces of 14-1,1
4-2, ......14-n, and a plurality (n-1) of thin films that cannot pass light 15-1, 15-2,
・・・・・・・・・15-(n-1) and 14-1 sequentially
,15-1,14-2,15-1,...
15-(n-1) and 14-n are stacked and arranged in the order of thin films 14-1, 14-2, .
・A structure in which one or more of the same thin films as the thin film 12 are stacked and arranged in connection with one or more of the thin films 14-n (in the figure, the lowest thin film 12-n) 12-n), one or more of the multi-channel optical paths can provide an optical switch function, and various other modifications can be made.

[Brief explanation of the drawing]

1 and 2 are a schematic perspective view and a side view showing a conventional thin film optical switch, respectively, FIG. 3 is a schematic side view showing a first embodiment of a thin film switch according to the present invention, and FIG. is a curve diagram showing the reflection angle of light within the thin film with respect to the thickness of the thin film, FIGS. 5 and 6 are line side views showing the second and third embodiments of the present invention, and FIG. FIG. 8 is a schematic side view showing still another embodiment of the present invention. In the figure, 1 and 11 are substrates, 2, 12 and 14 are thin films, 3 and 4 are prisms, 5 is a slit, 6 is an external optical circuit, 7 and 8 are electrodes, and L, L' and Pi are lights, respectively.

Claims (1)

[Claims] 1. A thin film containing azobenzene, or at least a thin film containing azobenzene and a thin film adjacent thereto, so as to allow light to propagate to the thin film containing azobenzene or the thin film adjacent thereto. , a thin film light characterized in that an optical switch function is obtained by changing the refractive index of the azobenzene-containing thin film in response to irradiation of the azobenzene-containing thin film with light having a predetermined wavelength; switch. 2 A thin film containing azobenzene, or a thin film containing azobenzene, and a thin film adjacent thereto, so as to allow light to propagate to the thin film containing said azobenzene or a thin film adjacent thereto, and containing said azobenzene. By changing the refractive index of the azobenzene-containing thin film in response to irradiation of the thin film with light having a predetermined wavelength, the optical path of the light propagating to the azobenzene-containing thin film or a thin film adjacent thereto is changed. A thin film optical switch characterized by being designed to provide a switching function. 3 A thin film containing azobenzene, or a thin film containing azobenzene and a thin film adjacent thereto, which are configured to allow light to propagate to the thin film containing said azobenzene or a thin film adjacent thereto, and containing said azobenzene. With the thin film selected to have a predetermined thickness, the refractive index of the azobenzene-containing thin film is changed in response to irradiation of the azobenzene-containing thin film with light having a predetermined wavelength, so that an optical switch function can be obtained. A thin film optical switch characterized by the following.