JPS626204A - Optical demultiplexer - Google Patents

Abstract

PURPOSE:To easily unite optical fibers with a dielectric and to form an optical demultiplexer in a simple shape by using a ceramic capillary atop the optical fibers and also using a curved diffraction grating which is plane and converges light. CONSTITUTION:The fiber core 15 of an optical fiber 3 is fitted to a ceramic capillary 9 at its end, and optical fibers 4, 5, 6, 7, and 8 are the same and inserted into recesses parts formed in one end surface of the transparent prismatic dielectric 2, which is united with the optical fibers 3, 4, 5, 6, and 7 by using a material which ha a refractive index almost equal to that of the optical fibers. Light having five different wavelengths is made incident on the plane curved refraction grating 1 from the input light optical fiber 3 through the dielectric 2 and then the light is wavelength-dispersed and reflected at different angles corresponding to the wavelengths, and also converged by the plane curved diffraction grating 1, so that light beams having the respective wavelengths are photodetected by the optical fibers 4, 5, 6, 7, and 8.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an optical demultiplexer used for optical wavelength multiplexing transmission in optical fiber communications.

BACKGROUND OF THE INVENTION In recent years, optical wavelength division multiplexing transmission technology has been used as a means for increasing transmission capacity by effectively utilizing optical fibers in optical fiber transmission.

An example of the conventional optical demultiplexer mentioned above will be described below with reference to the drawings.

FIG. 2 shows a conventional optical demultiplexer. In FIG. 2, 21 is a concave diffraction grating, 22 is a transparent dielectric material, and 23 is a concave diffraction grating.
24, 25 and 26 indicate input optical fibers, and output optical fibers 23, 24, 25, 26 are placed in contact with the transparent dielectric 22. The operation of the optical demultiplexer configured as described above will be explained below.

By inputting light having three different wavelengths from the input optical fiber 23 to the concave diffraction grating 21 via the dielectric 22, the light undergoes wavelength dispersion and is reflected at different angles for each wavelength. and converged on the concave surface, and the lights with different wavelengths are sent to the output optical fiber 24.25.2.
The light is received at 6. (For example, "1986 Institute of Electronics and Communication Engineers Hikari.

(National Conference on Radio Waves, Pages 33-2424 to 426) Problems to be Solved by the Invention However, with the above configuration, it is difficult to join the optical fiber and the dielectric material, and the fiber core wire is thin and easily breaks. Problematic and concave mll
It is said that it is very difficult to make an origami, and that the transparent dielectric material also needs to be processed into a convex shape in order to be bonded to the concave diffraction grating, which requires a very complicated man-hour. I had a problem.

The present invention takes the above-mentioned problems into consideration and provides an optical demultiplexer that is easy to fabricate by using a planar curved diffraction grating that facilitates the joining of a dielectric material and an optical fiber and has a planar and light focusing effect. It is something.

Means for Solving the Problems In order to solve the above problems, the optical demultiplexer of the present invention includes a planar curved diffraction grating in which curved grating grooves are formed on the surface of a planar reflection plate, and the planar curved diffraction grating. a plurality of optical fibers arranged in a space in front of the diffraction grating so as to input light to the diffraction grating and receive light from the diffraction grating; a dielectric, a recess is provided on one end surface of the dielectric, and a ceramic capillary (
A plurality of optical fibers each having a core attached thereto are inserted, and a plurality of wavelengths are incident on the diffraction grating from the one optical fiber through the dielectric, and each of the other optical fibers is connected to the plane curved diffraction grating. This device is configured to receive diffracted light having different wavelengths.

Function The present invention uses a ceramic capillary at the tip of an optical fiber to facilitate and strengthen the joining of optical fibers, and also uses a planar curved diffraction grating that focuses light. As a result, the shape of the transparent outer dielectric that propagates the light from the optical fiber can be flat, and an optical demultiplexer with a simple structure and easy to manufacture can be realized.

Embodiment An optical demultiplexer according to an embodiment of the present invention will be described below with reference to the drawings.

FIGS. 1(-) and 1(b) show an optical demultiplexer in an embodiment of the present invention. In FIG. 1, reference numeral 1 indicates a planar curved diffraction grating, in which curved grating grooves are formed on the surface of a planar reflection plate so as to have a light focusing effect. 2 shows a transparent prismatic dielectric. 3 is the input optical fiber, 4, 5,
6, 7.8 indicates an output optical fiber, and the optical fiber 3
The end of the fiber core 1 is connected to the fiber core 1 as shown in FIG.
5 is attached to the ceramic capillary 9,
The optical fibers 4, 5, 6, 7.8 are similarly attached to ceramic capillaries 10, 11, 12, 13, 14, and these optical fibers are connected to one end face of the transparent prismatic dielectric body 2. It is inserted into the recess provided,
The transparent prismatic dielectric 2 and optical fibers 3, 4, 5, 6
．． The optical fiber and the optical fiber are joined with a material having substantially the same refractive index as the optical fiber.

Still, the refractive index of the prismatic dielectric material has approximately the same value as the refractive index of the optical fiber.

On the other hand, the planar curved diffraction grating 1 is also bonded to a transparent dielectric material 2 made of a material having approximately the same refractive index as the optical fiber.

In the above-mentioned configuration, by inputting the light consisting of five different wavelengths from the input optical fiber 3 into the plane curve diffraction grating 1 via the dielectric 2, the light returning from the six different wavelengths has a different wavelength. The light is dispersed and reflected at different angles for each wavelength, and is focused by the plane curved diffraction grating 1.
, 7°8.

As described above, according to this embodiment, the strength is increased by attaching an optical fiber core wire as thin as an elbow to a ceramic capillary, and the ceramic capillary is attached by providing a recess in one end face of the prismatic dielectric body. Inserting the optical fiber facilitates coupling the optical fiber to the dielectric.

Furthermore, by using a flat curved diffraction grating as a wavelength dispersion element, the substrate on which the diffraction grating is formed can be made flat, and by using a flat curved diffraction grating, it can serve as a light propagation path. The shape of the transparent dielectric material can be made into a prismatic shape that is very easy to process, which facilitates its manufacture.

Furthermore, by making the refractive index of the prismatic dielectric material and the material for joining the optical fiber and the dielectric material and the planar curved diffraction grating and the dielectric material almost the same as the refractive index of the optical fiber, the refractive index of each portion can be adjusted. By minimizing optical loss, it is possible to realize an optical demultiplexer with low loss.

Effects of the Invention As described above, the present invention facilitates the bonding of an optical fiber and a dielectric material by using a ceramic capillary, and by using a plane curved diffraction grating,
The optical demultiplexer can be constructed from an optical member having a very simple shape, making it extremely easy to manufacture the optical demultiplexer.

[Brief explanation of the drawing]

FIG. 1(a) is a perspective view of an optical demultiplexer according to an embodiment of the present invention, FIG. 1(a) is a diagram showing the assembly of a ceramic capillary and an optical fiber, and FIG. It is a diagram. 1... Planar curved diffraction grating, 2... Transparent prismatic dielectric, 3... Input optical fiber, 4,
5, 6, 7° 8... Output optical fiber, 9, 10
, 11.12゜13.14... Ceramic capillary, 15... Fiber core wire. Name of agent: Patent attorney Toshio Nakao and 1 other person #
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Claims (1)

[Claims] a plane curved diffraction grating in which curved grating grooves are formed on the surface of a plane reflector, and a space in front of the diffraction grating so that light is incident on the plane curved diffraction grating and light from the diffraction grating is received. a transparent dielectric filling the space between the diffraction grating and the optical fibers, a recess is provided in one end surface of the dielectric, and the optical fiber is arranged in the recess. A plurality of optical fibers each having a ceramic capillary attached to the tip thereof are inserted, and a plurality of wavelengths are incident on the diffraction grating from the one optical fiber through the dielectric, and each of the other optical fibers is connected to the plane curve diffraction. An optical demultiplexer that receives light of different wavelengths diffracted by a grating.