JPS626207A - Optical demultiplexer - Google Patents

Abstract

PURPOSE:To constitute an optical demultiplexer in an extremely simple shape by using a plane curved diffraction grating. CONSTITUTION:Curved diffraction grooves are formed in the surface of the plane transmission plate of a dielectric 1 where the plane curved diffraction grating is formed so as to have light converging effect. An end part of an optical fiber 3 is inserted into a recessed part formed in one end surface of the dielectric 1 where the plane curved diffraction grating is formed. End parts of optical fibers 4, 5, 6, 7, and 8, on the other hand, are inserted into recessed parts formed in one end surface of a transparent prismatic dielectric 2 and the dielectrics 1 and 2 are jointed together by using a material whose refractive index is nearly equal to that of the optical fibers. Light having five different wavelengths is made incident on the plane curved diffraction grating from the input optical fiber 3 through the dielectric, and than this 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 mutually different wavelengths are photodetected by the output 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 division multiplexing transmission in optical fiber communication. An example of the above-mentioned conventional optical demultiplexer will be described with reference to the subzero drawing, which is used as a means of increasing transmission capacity by effectively utilizing optical fibers in fiber transmission.

FIG. 2 shows a conventional optical demultiplexer. In FIG. 2, 11 is a concave diffraction grating, 12 is a transparent dielectric material, and 13 is a concave diffraction grating.
14, 15 and 16 are input optical fibers, and the optical fibers 13, 14, 15, 16 are placed in contact with the transparent dielectric 12 and are constructed as shown in FIG. The operation of the optical demultiplexer will be explained below.

By inputting light consisting of three different wavelengths from the input optical fiber 13 into the concave opening/grating 11 through the dielectric 12, the light undergoes wavelength dispersion, and the light is distributed at different angles for each wavelength. The light beams that are reflected and converged by the concave surface, each having a different wavelength, are sent to output optical fibers 14, 15 .
The light is received at 16. (For example, "1986 Institute of Electronics and Communication Engineers National Conference on Optical and Radio Division JSs-2424 pages ~ 4
(Page 25) Problems to be Solved by the Invention However, with the above configuration, it is very difficult to create a concave diffraction grating, and it is difficult to bond the transparent dielectric material to the concave diffraction grating. , it is necessary to process it into a convex shape, which has the problem of requiring a very complicated number of man-hours.

The present invention takes the above-mentioned problems into consideration and provides an optical demultiplexer that is easy to manufacture using a transmission type plane curved diffraction grating that is planar and has a light focusing effect.

Means for Solving the Problems In order to solve the above problems, the optical demultiplexer of the present invention combines a dielectric material forming a plane curved diffraction grating and a transparent prismatic dielectric hole to form a plane curved diffraction grating. and a plurality of optical fibers arranged in a space in front of the diffraction grating so as to input light into the planar curved diffraction grating and to receive light from the diffraction grating, the diffraction grating and the optical fibers being arranged in a space in front of the diffraction grating. and a transparent dielectric material filling the space between the two optical fibers, and a plurality of wavelengths are incident on the diffraction grating from one optical fiber through the dielectric material, and each of the other optical fibers is diffracted by the planar curved diffraction grating. The device is configured to receive light of different wavelengths.

Effect of the Invention The present invention has the above-described configuration, and by using a planar curved diffraction grating that focuses light, the shape of the transparent dielectric material that propagates the light from the optical fiber can also be a planar shape, and has a simple structure. This makes it possible to realize an optical demultiplexer that is easy to fabricate.

EXAMPLE Hereinafter, an optical demultiplexer according to an example of the present invention will be described with reference to the drawings.

FIG. 1 shows an optical demultiplexer in an embodiment of the present invention. In Fig. 1, numeral 1 indicates a dielectric material on which a planar curved diffraction grating is formed, and numeral 02 indicates a transparent prismatic dielectric material on which curved grating grooves are formed so as to have a light focusing effect on the surface of the planar transmission plate. Show your body.

Reference numeral 3 indicates an input optical fiber, and reference numerals 4, 5, 6, and 7.8 indicate output optical fibers, and the end of the optical fiber 3 is provided on one end surface of the dielectric 1 forming the plane curved diffraction grating. inserted into the recess. On the other hand, the optical fibers 4, 6,
The ends of 6, 7 and 8 are provided on one end face of the transparent prismatic dielectric 2 and inserted into the recess, and are connected to the dielectric 1 forming the plane curved diffraction grating, the optical fiber 3, and the optical fiber 3. Transparent prismatic dielectric 2 and optical fiber j, 6, 7, 8°9
and are joined together with a material having substantially the same refractive index as the optical fiber. - Furthermore, the refractive index of the prismatic dielectric body 2 has approximately the same value as the refractive index of the optical fiber.

On the other hand, the dielectric material 1 in which a plane curved diffraction grating is formed also has the following characteristics.
The optical fiber is made of a material having almost the same refractive index as the optical fiber and is bonded to a transparent dielectric material 2.

In the above-mentioned configuration, by inputting the light consisting of six different wavelengths from the input optical fiber 3 into the plane curve diffraction grating via the dielectric, the light consisting of the six different wavelengths undergoes wavelength dispersion. Each wavelength is reflected at a different angle and is focused by the plane curved diffraction grating 1, and the light having different wavelengths is received by the output optical fiber 4°5.6, 7.8 through the dielectric 2. .

As described above, according to this embodiment, by using a curved diffraction grating as a wavelength dispersion element, the substrate for forming the diffraction grating can be made flat, and by using a flat curved diffraction grating, the substrate can be made flat. The shape of the transparent dielectric material that serves as a light propagation path can be made into a prismatic shape that is very easy to process, which facilitates its manufacture.

Further, in this embodiment, a recess is provided in one end face of the two prismatic dielectric bodies and an optical fiber is inserted into the concave portion, thereby facilitating coupling of the optical fiber to the dielectric body.

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 approximately 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 allows an optical demultiplexer to be constructed from optical members having a very simple shape by using a plane curved diffraction grating, making it extremely easy to manufacture an optical demultiplexer. It can be done.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an optical demultiplexer according to an embodiment of the present invention, and FIG. 2 is a perspective view of a conventional optical demultiplexer. 1...Dielectric material forming a plane curved diffraction grating, 2
. . . Transparent prismatic dielectric, 3 . . . Input optical fiber, 4.5, 6, 7.8 . . . Output optical fiber.

Claims (1)

[Claims] a dielectric material forming a planar curved diffraction grating and a transparent prismatic dielectric material are joined together, and one optical fiber is arranged in a space in front of the diffraction grating so as to input light into the planar curved diffraction grating; a plurality of optical fibers arranged in a space behind the diffraction grating so as to receive light from the diffraction grating;
A plurality of wavelengths are incident on the diffraction grating from the single optical fiber, and a plurality of optical fibers arranged in a space behind the diffraction grating receive light of different wavelengths diffracted by the diffraction grating. Characteristic optical demultiplexer.