JPS61285412A - Optical multiplexer and demultiplexer - Google Patents

Abstract

PURPOSE:To easily manufacture an optical multiplexer and demultiplexer by using one face of a glass block as a total reflection surface and the other face as an exit face inclined with the incient face parallel with the reflection surface and forming multi-layered dielectric films by simultaneous vapor deposition on part/whole of the incident face and the exit face. CONSTITUTION:One face of the glass block 1 is used as the total reflection face 2 and the other face is used as the exit face 4 inclined with the incident face 3 parallel with the face. The multi-layered dielectric films 5a, 5b are formed on part or the whole of the incident face 3 and the exit face 4 by the simultaneous vapor deposition. The thickness of the dielectric film is smaller on the incident face 3 when the film is deposited by evaporation in the direction perpendicular to the exit face 4 and there fore the multi-layered films 5a, 5b have different wavelength characteristics. The light of wavelengths lambda1, lambda2 (where lambda1<lambda2) is reflected by the face 2 when said light is made incident on the incident face 3 on which the film 5a is not formed. The reflected light is made incident on the film 5a formed on the face 3 and only the light of the wavelength lambda1 is transmitted therethrogh. The light of the other wavelength is reflected therefrom. The reflected light is reflected by the total reflection face 2 and enters the film 5b through which the light of the wavelength lambda2 is transmitted.

Description

[Detailed Description of the Invention] [Summary] Dielectric multilayer films are formed by simultaneous vapor deposition on the faces of glass blocks with different angles, and since the dielectric film thicknesses formed on the faces with different angles are different, Dielectric multilayer films formed on different surfaces have different wavelength characteristics.

Therefore, it is possible to perform demultiplexing or multiplexing of light having different wavelengths.

[Industrial application field]

The present invention relates to an optical demultiplexer/multiplexer that performs demultiplexing or multiplexing of lights of different wavelengths in optical wavelength division multiplexing communications and the like.

In optical communication systems, like frequency division multiplex communication systems,
2. Description of the Related Art Optical wavelength multiplexing communication systems are known in which light having different wavelengths is multiplexed and transmitted, and for this purpose, it is necessary to separate or combine light having different wavelengths with a simple configuration. Furthermore, it is desired that a narrowband bandpass filter can be easily constructed in order to extract only an optical signal of a desired wavelength.

[Conventional technology]

A conventional optical demultiplexer/multiplexer, for example, as shown in FIG.
A dielectric multilayer film 13 that transmits wavelength λ2 is formed on a part of one surface of the cubic glass block 11 by vapor deposition or the like, and a dielectric multilayer film 12 that transmits seven wavelengths is formed on a part of the other surface. It has a structure in which it is formed by vapor deposition or the like.

Wavelength λ1. from one side of glass block 11. When light of wavelength λ2 is incident, only light of wavelength λ1 is transmitted through the dielectric multilayer film 12 formed on the other surface, and light of other wavelengths is reflected. This reflected light is transmitted through the dielectric multilayer film 1 formed on one surface.
3 and only the light with the wavelength λ2 is transmitted, so the dielectric multilayer film 12 can separate the light with the wavelength λ1, and the dielectric multilayer film 13 can separate the light with the wavelength λ2.

On the contrary, the light with the wavelength λ2 is made incident on the dielectric multilayer film 13,
When light with wavelength λ1 is incident on dielectric multilayer film 12, light with wavelength λ2 passes through dielectric multilayer film 13 and is reflected by dielectric multilayer film 12, and light with wavelength λ1 enters dielectric multilayer film 12. , the lights of wavelengths λ■ and λ2 are combined and output.

[Problem that the invention seeks to solve]

In conventional optical demultiplexing/combining devices, the dielectric multilayer films 12 and 13 having the desired transmission wavelength are formed directly on the glass block 11 or are formed on glass plates and then bonded together. The disadvantage was that it was complicated. Furthermore, it has not been easy to construct a narrow band pass filter.

An object of the present invention is to enable manufacturing through simple steps.

[Means for solving problems]

The optical demultiplexer/multiplexer of the present invention will be described with reference to FIG. 3 and inclined exit surface 4
Dielectric multilayer films 5a and 5b are formed on a glass block 1, a part or all of the entrance surface 3, and the exit surface 4 of the glass block 1 by simultaneous vapor deposition.

[Effect]

The dielectric multilayer films 5a and 5b formed by simultaneous vapor deposition on the entrance surface 3 and the exit surface 4 of the glass block l are dielectric multilayer films formed on the exit surface 4, assuming that the vapor deposition direction is perpendicular to the exit surface 4. The thickness of the film becomes thicker than the thickness of the dielectric film formed on the incident surface 3.

Therefore, the wavelength λ1. reflected by the total reflection surface 2. Of the light of λ2, only the wavelength λ1 (λ + λ2) is transmitted through the dielectric multilayer film 5.
a is transmitted, and light of other wavelengths is reflected. When this reflected light is reflected by the total reflection surface 2 and incident on the dielectric multilayer film 5b formed on the output surface 4, only the light having the wavelength λ2 is transmitted.

Therefore, it is possible to separate or combine lights of different wavelengths. Furthermore, by selecting the angular relationship between the entrance surface 3 and the exit surface 4, the wavelength characteristics of the dielectric multilayer films 5a and 5b formed on the entrance surface 3 and the exit surface 4 partially overlap. can be configured.

〔Example〕

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

FIG. 1 is an explanatory diagram of an embodiment of the present invention, in which one surface of a glass block 1 is a total reflection surface 2, and the other surface is an incident surface 3 parallel to the total reflection surface 2 and an inclined output surface. As side 4,
Part or all of the entrance surface 3 and the exit surface 4 are formed by simultaneous vapor deposition.
Additionally, dielectric multilayer films 5a and 5b are formed.

When vapor deposition is performed in a direction perpendicular to the exit surface 4, the thickness of the dielectric film deposited on the entrance surface 3 becomes thinner in accordance with the angular relationship between the exit surface 4 and the entrance surface 3. . Therefore, the wavelength characteristics of the dielectric multilayer films 5a and 5b that have been simultaneously deposited are different.

Therefore, the entrance surface 3 on which the dielectric multilayer film 5a is not formed
, the wavelength λ3. When light with a wavelength of λ2 (λ1 × λ2) is incident, it is reflected by the total reflection surface 2 and enters the dielectric multilayer film 5a formed on the incident surface 3, and only the light with a wavelength of λ is transmitted. Wavelengths of light are reflected. This reflected light is reflected by the total reflection surface 2, enters the dielectric multilayer film 5b formed on the output surface 4, and the light of wavelength λ2 is transmitted. Therefore,
Wavelength λ1. It can separate the light of λ2 and becomes an optical demultiplexer.

On the other hand, when light with a wavelength λ2 is made incident on the dielectric multilayer film 5b formed on the output surface 4, and light with a wavelength λelectric is made incident on the dielectric multilayer film 5a formed on the entrance surface 3, the light with the wavelength λ2 is made incident on the dielectric multilayer film 5b formed on the emission surface 4. The light passes through the dielectric multilayer film 5b, is reflected by the total reflection surface 2, and enters the dielectric multilayer film 5a formed on the incident surface 3.
The light is reflected by this dielectric multilayer film 5a. Also, light with seven wavelengths passes through this dielectric multilayer film 5a. Therefore, the wavelength λhλ
The two lights are reflected and reflected by the total reflection surface 2, and are combined and emitted from the incidence surface 3, forming an optical multiplexer.

FIG. 2 is an explanatory diagram of wavelength characteristics, where curve a shows the wavelength characteristics of the dielectric multilayer film 5a, curve 2 shows the wavelength characteristics of the dielectric multilayer film 5b, and the dielectric multilayer film 5a formed by simultaneous vapor deposition,
5b, the wavelength λ3. It is possible to perform demultiplexing or multiplexing of light of λ2.

FIG. 3 is an explanatory diagram of simultaneous vapor deposition, and when forming the dielectric multilayer films 5a and 5b having the structure shown in FIG. 1, vapor deposition is performed in a direction perpendicular to the emission surface 4. The dielectric multilayer film is generally formed by alternately stacking T i O2 and 5t02, and the T i O2 formed on the emission surface 4
The thickness of 02 is tI+ t*+'3+..., and 5ioz
The thickness is 'I+'! +'! +..., the output surface 4
T formed on the entrance surface 3 according to the angle θ between and the entrance surface 3
The thickness of i O2 and S i O2 is -L+CO3θ,!
+CO! l θ, tgcos θ, 5zcos θ, t3
cos θ, s, cos θ, . . . In addition, 6
1 shows a mask for preventing the dielectric multilayer film 5a from being formed on a part of the incident surface 3. FIG.

As mentioned above, by performing simultaneous vapor deposition on the entrance surface 3 and the exit surface 4, the dielectric multilayer film 5 having the wavelength characteristics shown in FIG.
a, 5b can be formed, and if the glass block 1 is placed in a vapor deposition apparatus so as to be vapor-deposited in a direction perpendicular to the incident surface 3, as shown by the dotted line, a dielectric multilayer film can be formed.
Contrary to the above case, the thickness of the dielectric film formed on the exit surface 4 is proportional to CO3θ with respect to the thickness of the dielectric film formed on the entrance surface 3.

FIG. 4 is an explanatory diagram of another embodiment of the present invention, and the glass block 1, total reflection surface 2, entrance surface 3, and exit surface 4 are the same as those in the above-mentioned embodiment.

In this embodiment, dielectric multilayer films 5c and 5d are formed by simultaneous vapor deposition on the entire surfaces of the entrance surface 3 and the exit surface 4, and in this case, the dielectric multilayer films 5c and 5d are deposited in a direction perpendicular to the entrance surface 5. It is. Therefore, the dielectric multilayer film 5c formed on the incident surface 3
is thicker than the dielectric multilayer film 5d formed on the emission surface 4. Then, when light is made incident on the dielectric multilayer film 5c, light with a wavelength according to the wavelength characteristics of the dielectric multilayer film 5C is transmitted,
The light is reflected by the total reflection surface 2 and is incident on the dielectric multilayer M5d. Since light with a wavelength according to the wavelength characteristics of the dielectric multilayer film 5d is transmitted, the wavelength characteristics are a combination of the wavelength characteristics of the dielectric multilayer film 5C and the wavelength characteristics of the dielectric multilayer film 5d.

The center wavelength of the pass band formed on the dielectric multilayer film 5C formed on the incident surface 3 is λ3, and the center wavelength of the pass band formed on the dielectric multilayer film 5d formed on the output surface 4 is λ4.
．． As shown in FIG. 5, the wavelength characteristic curve C of the dielectric multilayer film 5C and the wavelength characteristic curve d of the dielectric multilayer film 5d are selected so that they partially overlap (the angle between the incident surface 3 and the exit surface 4). θ), the synthesized wavelength characteristic has a narrow passband W with a center wavelength λ0. Therefore, a narrow bandpass filter can be constructed.

Incidentally, the entrance surface 3 and the exit surface 4 of the glass block 1 are the names used when light enters in FIGS. 1 and 4, and the light enters from the exit surface 4, This also includes the case where light is emitted from the entrance surface 3.

〔Effect of the invention〕

As explained above, in the present invention, one surface of the glass block 1 is a total reflection surface 2, the other surface is an entrance surface 3 parallel to the reflection surface 2, and an inclined exit surface 4. The dielectric multilayer films 5a and 5b are formed by simultaneous vapor deposition on a part or all of the incident surface 3 and the emission surface 4, and by performing simultaneous vapor deposition on the incident surface 3 and the emission surface 4 at different angles, different wavelength characteristics can be obtained. It becomes possible to simultaneously form dielectric multilayer films, and it becomes possible to easily manufacture an optical demultiplexer or an optical multiplexer. Another advantage is that a narrow band pass filter for extracting only light of a desired wavelength can be easily manufactured.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of one embodiment of the present invention, Fig. 2 is an explanatory diagram of wavelength characteristics, Fig. 3 is an explanatory diagram of simultaneous vapor deposition, Fig. 4 is an explanatory diagram of another embodiment of the present invention, and Fig. 5 is an explanatory diagram of another embodiment of the present invention. The figure is an explanatory diagram of wavelength characteristics, and FIG. 6 is an explanatory diagram of a conventional example. 1 is a glass block, 2 is a total reflection surface, 3 is an incident surface, 4 is an exit surface, and 5a, 5b, 5c, and 5d are dielectric multilayer films.

Claims (1)

[Claims] One surface is a total reflection surface (2), and the other surface is an entrance surface (3) parallel to the reflection surface (2) and an inclined exit surface (
4); a part or all of the incident surface (3); and the exit surface (4).
An optical demultiplexing/combining device comprising dielectric multilayer films (5a) and (5b) having different wavelength characteristics formed by simultaneous vapor deposition.