JPH11109151A - Optical wavelength composing and dividing equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the manufacture of a wavelength composing and dividing equipment and solve the deterioration of its optical characteristic resulted from the discordance between the thickness of a filter and width of a groove by dispensing with a wavelength composing and dividing filter set within the groove. SOLUTION: This optical wavelength composing and dividing equipment is provided with an optical fiber having a wavelength composing and dividing filter membrane 81 for transmitting a first wavelength light and reflecting a second wavelength light formed on one end part thereof, and an optical waveguide 32 having one end surface opposed to the end surface of the optical fiber having the wavelength composing and dividing filter membrane 81 formed thereon, and crossing thereto in the end surface. Otherwise, this optical wavelength composing and dividing equipment is provided with an optical fiber having one end surface formed obliquely to the axial direction and a wavelength combining and dividing filter membrane 81 formed on this end surface, and an optical waveguide set so that its end surface is opposed to the side surface of one end part of the optical fiber, and its axis is symmetric to the axis of the optical fiber to the normal line of the wavelength composing and dividing filter membrane 81.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical wavelength multiplexer / demultiplexer for multiplexing or demultiplexing light of a plurality of wavelengths.

[0002]

2. Description of the Related Art In optical communication, an optical wavelength multiplexing system for transmitting light of a plurality of wavelengths through one transmission line has been proposed in order to transmit a large amount of information and simultaneously enable bidirectional information transmission. Used. The optical wavelength division multiplexing system includes a wavelength multiplexer that combines light of a plurality of wavelengths coming from different transmission paths into one, and a wavelength multiplexer / demultiplexer that separates light of a plurality of wavelengths included in one transmission path. is necessary. By using a wavelength multiplexer / demultiplexer that functions both as a wavelength multiplexer and a wavelength demultiplexer, an optical wavelength division multiplexing system can be efficiently configured.

FIG. 8 shows a conventional optical wavelength multiplexer / demultiplexer. A narrow groove 11 is formed in a substrate 10, and a multiplexing / demultiplexing filter 2 that transmits a first wavelength and reflects light of a second wavelength is formed in the narrow groove 11.
0 is set. The multiplexing / demultiplexing filter 20 is typically formed of a dielectric multilayer film in which, for example, SiO ₂ and TiO ₂ are alternately laminated on a transparent substrate. Also, substrate 1
0 has one end on its end face and the other end is a narrow groove 11.
And optical waveguides 31A and 31B are formed at locations where the multiplexing / demultiplexing filter 20 is installed, the optical waveguides 31A and 31B intersecting each other so that the directions of the axes are symmetric with respect to the surface normal of the multiplexing / demultiplexing filter 20. ing. Further, the optical waveguide 31
A, the optical waveguide 31B has an end face facing the end face where the optical waveguide 31B intersects, and the optical waveguide 32 is formed on the extension of the optical waveguide 31A. The optical waveguide 32 is Y-branched, and opposes the light-emitting end 51 and the light-receiving end 61 such that the ends of the branches are optically coupled to the light-emitting element 50 and the light-receiving element 60 of the first wavelength, respectively. doing. An optical fiber 70A and an optical fiber 70B are respectively installed facing the end faces of the optical waveguide 31A and the optical waveguide 31B.

[0004] Light in which light of the first wavelength and light of the second wavelength are mixed is injected into the optical waveguide 31A through the optical fiber 70A. The light that has passed through the optical waveguide 31A enters the multiplex / demultiplex filter 20 from the other end face. The light of the first wavelength passes through the multiplexing / demultiplexing filter 20, enters the optical waveguide 32, and reaches the light receiving element 60. The light of the second wavelength is coupled to the multiplexing / demultiplexing filter 2.
Since it is reflected by 0, it passes through the optical waveguide 31B and enters the optical fiber 70B. In this way, the mixed light of the first wavelength and the second wavelength is split.
The first light emitted from the light emitting element 50 is
2. The light passes through the multiplexing / demultiplexing filter 20, is injected into the optical waveguide 31A, and enters the optical fiber 70A from the end face of the optical waveguide 31A. In this way, bidirectional optical communication with light of the first wavelength and unidirectional optical communication with light of the second wavelength are performed by the optical wavelength demultiplexer.

Further, if a light emitting element of the second wavelength is provided instead of the light receiving element of the second wavelength provided at the other end of the optical fiber 70B, the light of the second wavelength in this light emitting element is provided. And the first wavelength light from the light emitting element 50
The light beams can be multiplexed and sent to the optical waveguide 31A.

As described above, the conventional wavelength multiplexer / demultiplexer multiplexes and demultiplexes light of a plurality of wavelengths by the multiplexing / demultiplexing filter 20 installed in the groove. Since the multiplexing / demultiplexing filter 20 does not have a mechanism for confining light such as an optical waveguide,
When it is thick, there is a disadvantage that light loss due to light diffusion is apt to occur. In order to reduce this optical loss, it is necessary to make the thickness of the multiplexing / demultiplexing filter 20 thinner, for example, by making the transparent substrate constituting the multiplexing / demultiplexing filter 20 thinner. As a result, a filter of about 10 μm is generally used as the Z multiplexing / demultiplexing filter 20. On the other hand, the width of the groove is preferably narrow, corresponding to the thickness of the multiplexing / demultiplexing filter 20, but is limited to about 20 μm due to processing of the substrate with a dicing saw or the like. Formation is not easy. In addition, since there is a mismatch between the thickness of the multiplexing / demultiplexing filter 20 and the width of the groove, the multiplexing / demultiplexing filter 2 is manufactured when the wavelength multiplexing / demultiplexing device is manufactured or used.
0 tends to be inclined in the groove, and as a result, the optical characteristics of the wavelength multiplexer / demultiplexer often deteriorate.

[0007]

SUMMARY OF THE INVENTION In view of the above situation, the present invention eliminates the need for a multiplexing / demultiplexing filter installed in a groove, thereby facilitating the production of a wavelength multiplexing / demultiplexing device with small optical loss. Further, it is an object of the present invention to eliminate the deterioration of the optical characteristics caused by the mismatch between the thickness of the filter and the width of the groove.

[0008]

According to the present invention, there is provided an optical fiber having at one end thereof a multiplexing / demultiplexing filter film for transmitting light of a first wavelength and reflecting light of a second wavelength. An optical wavelength multiplexer / demultiplexer having an optical waveguide having an end face and an end face of an optical fiber on which a wave filter film is formed and intersecting at the end face.

Also, in the present invention, an optical fiber in which one end face is formed obliquely with respect to the axial direction and a multiplexing / demultiplexing filter film is formed on the end face, and the end face is formed on the side face of the end of the optical fiber. An optical wavelength multiplexer / demultiplexer is provided which has an optical waveguide which is opposed to the optical fiber and whose axis is symmetric with respect to the axis of the optical fiber with respect to the surface normal of the multiplexer / demultiplexer filter film.

[0010]

1 and 2 show a first embodiment of the present invention. FIG. 2 shows the light emitting element 50 and the light receiving element 6 from FIG.
0 and a state where the optical fiber with filter 80 is removed. A wide groove 12 and a wide groove 14 are formed in the substrate 10, and a V groove 16 is formed between the wide groove 12 and the wide groove 14. The optical waveguide 31 </ b> A is formed from the end face of the substrate 10 to the side face of the wide groove 12, and one end thereof faces the end face of the V-groove 16, and is in a direction coinciding with the groove direction of the V-groove 16. Here, the side surfaces of the wide groove 12 and the wide groove 14 are inclined to the axis of the optical waveguide 31A. One end of the optical waveguide 31B intersects one end of the optical waveguide 31A on the side surface of the wide groove 12, and the other end faces the end surface of the substrate 10. One end of the optical waveguide 32 on the side surface of the wide groove 14 faces the end surface of the V-groove 16, and the other end side is thereafter branched in a Y direction. An engraving 18 is formed at the Y-branched tip of the optical waveguide 32.

In the V-groove 16, an optical fiber 80 with a filter is provided.
The light emitting element 50 and the light receiving element 60 are respectively installed on the two engravings 18. As the optical fiber with filter 80, either a single mode fiber or a multimode fiber can be used in some cases. If a multimode fiber is used, the alignment with the optical waveguides 31A and 32 becomes easy. It should be noted that TEC (Th) in which the core diameter of the single mode fiber is enlarged as a whole instead of the multimode fiber
thermally-Diffused Expanded
Core) fiber may be used. The optical fiber with filter 80 has an end face at both ends thereof having a wide groove 12.
And is formed obliquely with respect to its axis so as to be parallel to the wide groove 14. A multiplexing / demultiplexing filter film 81 that transmits light of the first wavelength and reflects light of the second wavelength is provided on both end surfaces of the optical fiber 80 with a filter. Are formed respectively. The direction of the axis of the optical waveguide 31A and the direction of the axis of the optical waveguide 31B are symmetric with respect to the surface normal of the multiplexing / demultiplexing filter film 81. In FIG. 1, the surface of the cut filter film 82 is substantially parallel to the surface of the multiplexing / demultiplexing filter film 81 for the sake of clarity, but this is not necessarily the case. In addition, as the cut filter film 82, the same filter as the multiplexing / demultiplexing filter film 81 can be used as described later.

The material of the substrate 10 does not need to be particularly limited. However, when silicon is used, the V-groove 16 can be formed very precisely by anisotropic etching, which is convenient. For the wide groove 12 and the wide groove 14, blade processing by a dicing saw can be applied. Here, the wide groove 12 and the wide groove 14 do not need to be reduced in width as in the conventional narrow groove 11, so that the processing is extremely easy. Various methods can be used for forming the optical waveguide. For example, a flame deposition method can be applied. here,
When the optical waveguide is a polymer waveguide formed of an organic material such as a polymer, the compatibility is good when the substrate 10 is made of silicon. This is because the polymer waveguide does not require a high temperature to induce a crystal defect inside silicon in its manufacturing process, so that it is easy to form the V-groove 16 with high precision after the polymer waveguide is manufactured.

The optical fiber with filter 80 is placed on the V-groove 16 after the formation of the multiplexing / demultiplexing filter film 81 and the cut filter film 82. The multiplexing / demultiplexing filter film 81 and the cut filter film 82 are, for example, dielectric multilayer films, and are formed by alternately laminating SiO ₂ and TiO ₂ films on the optical fiber with filter 80 by a film forming method such as a vacuum evaporation method. You can do that. If the multiplexing / demultiplexing filter film 81 and the cut filter film 82 are inclined at the same angle with respect to the axis of the optical fiber 80 with a filter, the multiplexing / demultiplexing filter film 81 and the cut filter film 82 can be formed under exactly the same conditions. No problem. here,
When the multiplexing / demultiplexing filter film 81 and the cut filter film 82 are formed on the optical fiber with filter 80, the material constituting the multiplexing / demultiplexing filter film 81 and the cut filter film 82 is partially applied to the side surface of the optical fiber with filter 80. Can also adhere and wrap around. The wide groove 12 and the wide groove 14 are
To form an escape against this wraparound,
There is an advantage that the installation of the optical fiber with filter 80 is not affected. The optical fiber with filter 80 can be appropriately fixed to the V groove 16 with an adhesive or the like. Further, in some cases, it can be fixed by pressing with a pressing plate from above in FIG.

Light having a mixture of light of the first wavelength and light of the second wavelength is injected from the end face of the optical waveguide 31A. This light enters the multiplex / demultiplex filter film 81 from the end face of the optical waveguide 31A on the side surface of the wide groove 12. At this time, the light of the first wavelength passes through the multiplexing / demultiplexing filter film 81, and the light of the second wavelength is reflected by the multiplexing / demultiplexing filter film 81. The light of the first wavelength passes through the core 85 of the optical fiber with a filter 80 and reaches the cut filter film 82. The cut filter film 82 removes, of the light that has passed through the core 85, a slight amount of light of the second wavelength that has not been separated by the multiplexing / demultiplexing filter film 81. That is, although the cut filter film 82 is not absolutely necessary, the addition of the cut filter film 82 reduces the mixing of the second light into the separated light of the first wavelength, and reduces the light with less error. Contribute to communication. The light of the first wavelength that has passed through the cut filter film 82 enters the optical waveguide 32 from the end and finally reaches the light receiving element 60, where it is detected. On the other hand, the second light reflected by the multiplexing / demultiplexing filter film 81 enters the optical waveguide 31B, exits from the end of the optical waveguide 31B, and appropriately enters an optical fiber or the like. The light emitting element 50 emits light of the first wavelength, and this light passes through the optical waveguide 32, the cut filter film 82, the core 85, and the multiplexing / demultiplexing filter film 81, and exits from the end of the optical waveguide 31A. In this way, transmission and reception with light of the first wavelength and transmission with light of the second wavelength are possible.

FIG. 3 shows a second embodiment of the present invention. This is a diagram of the optical multiplexer / demultiplexer viewed from the front. The optical waveguide 32 is removed, the light receiving element 60 is directly opposed to the cut filter film 82 on the end face of the optical fiber with filter 80, and the light emitting element 50A is provided at the end of the optical waveguide 31B. The points are different. The light emitting element 50A and the light receiving element 60 are appropriately aligned with the optical path by engraving or the like provided on the substrate 10, but this point is omitted. This omission is the same in the following drawings. The light of the first wavelength that enters from the optical waveguide 31A and passes through the multiplexing / demultiplexing filter 81 passes through the core 85 and directly enters the light receiving element 60 from the cut filter film 82. The light of the second wavelength emitted from the light emitting element 50A passes through the optical waveguide 31B and passes through the multiplex / demultiplex filter 81.
And is sent out from the optical waveguide 31A. As a result, reception with light of the first wavelength and transmission with light of the second wavelength are possible. In this embodiment, there is no optical waveguide after the cut filter film 82 and the light emitting element 50A is
By installing the optical wavelength multiplexing communication apparatus above, it is possible to reduce the size of the entire optical wavelength division multiplexing communication apparatus.

FIG. 4 shows a third embodiment which is a modification of the second embodiment of the present invention. Here, a multimode fiber having a particularly large NA is used for the optical fiber with filter 80. Also, the optical waveguides 31A and 31B have axial directions symmetric with respect to the surface normal of the multiplexing / demultiplexing filter film 81, respectively, as in the first and second embodiments. The surface of the cut filter film 82 is perpendicular to the axis of the optical fiber 80 with a filter. As a result, the axis of the optical fiber with filter 80 is aligned with the optical waveguide 31A.
Axis and direction are different. Optical fiber with filter 80
Is large, light emitted from the end face of the optical waveguide 31A on the side surface of the wide groove 12 efficiently enters the core 85 even if the axial direction differs from that of the optical waveguide 31A. In this embodiment, the surfaces of the multiplexing / demultiplexing filter film 81 and the cut filter film 82 are perpendicular to the axial direction of the optical fiber 80 with a filter. This does not cause a problem even if is rotated, making it easier to create an optical multiplexer / demultiplexer.

FIG. 5 shows a fourth embodiment of the present invention. Here, only the wide groove 12 is formed on the substrate 10. The optical fiber with filter 80 also has a multiplexing / demultiplexing filter film 81 formed only on one side. The end face of the optical waveguide 33 is opposed to the side face of one end of the optical fiber (80), and the multiplex / demultiplex filter film 8 of the optical fiber with filter 80 is provided.
It is installed symmetrically to the axis of the optical fiber with filter 80 with respect to one surface normal. The optical waveguide 32 is formed so as to face the multiplexing / demultiplexing filter film 81, and the light-emitting element 50 and the light-receiving element 60 are installed at the end of the Y branch. In this embodiment, the mixed light of the first wavelength light and the second wavelength light passes through the core 85 and enters the multiplex / demultiplex filter film 81. At this time, the light is reflected by the multiplex / demultiplex filter film 81. The light having the second wavelength passes through the optical fiber with filter 80 and enters the end face of the optical waveguide 33. The light of the first wavelength passes through the multiplexing / demultiplexing filter film 81 as it is, enters the optical waveguide 32, and reaches the light receiving element 60. The light of the first wavelength emitted from the light emitting element 50 passes through the optical waveguide 32 and the multiplexing / demultiplexing filter film 81 and enters the core 85. In this way, transmission and reception with light of the first wavelength and reception with light of the second wavelength are possible. In this embodiment, only one end face of the optical fiber with filter 80 needs to be installed on the substrate 10, and the first
Therefore, the optical waveguide 31A of the third embodiment is not required, and the optical coupling between the end of the optical waveguide 31A and the optical fiber is not required. Therefore, there is an advantage that the configuration of the optical multiplexer / demultiplexer is simplified.

FIG. 6 shows a fifth embodiment which is a modification of the fourth embodiment of the present invention. This is different from the fourth embodiment in that the optical waveguide 32 is removed, and the light emitting element 50 is placed directly opposite to the multiplexing / demultiplexing filter film 81 on the end face of the optical fiber 80 with a filter. Light receiving element 60
A is different. The light of the first wavelength emitted from the light emitting element 50 passes through the multiplexing / demultiplexing filter film 81 and enters the core 85, and the light of the second wavelength incident from the core 85 is reflected by the multiplexing / demultiplexing filter film 81. After passing through the optical waveguide 33, the light is received by the light receiving element 60A. Thus the first
, And reception with light of the second wavelength. In this embodiment, a Y-branched optical waveguide is not required, and the configuration of the optical multiplex communication device is simplified because the light receiving element 60A is provided on the substrate 10.

FIG. 7 shows a sixth embodiment which is a modification of the first embodiment of the present invention. This is different from the first embodiment in that the optical fiber with filter 80 is formed with a half mirror film 83 instead of the cut filter film 82, and the light guide 32 is removed so that the light emitting element 50 is formed on the half mirror film 83. The filter is directly opposed, and one end face is opposed to the side face of one end of the optical fiber with filter 80, and its axis is symmetric with respect to the axial direction of the core 85 and the surface normal of the half mirror film 83. A different point is that a simple optical waveguide 34 is formed, and a light receiving element 60 is provided at an end thereof. Here, the light of the first wavelength transmitted from the optical waveguide 31A through the multiplexing / demultiplexing filter film 81 and the core 85 is separated by the half mirror film 83 into transmitted light and reflected light. The reflected light is received by the light receiving element 60 through the optical waveguide 34. On the other hand, the light of the first wavelength emitted from the light emitting element 50 passes through the half mirror film 83,
The light enters the optical waveguide 34 from the core 85 and the multiplexing / demultiplexing filter film 81. That is, in this embodiment, the role of the Y-branched optical waveguide 32 in the first embodiment is replaced by the half mirror film 8.
3 is performed, and the optical multiplexer / demultiplexer is downsized while having the same function.

[0020]

As described above, the present invention eliminates the need for a multiplexing / demultiplexing filter installed in a groove, facilitates the production of a wavelength multiplexing / demultiplexing device with small optical loss, and eliminates the deterioration of optical characteristics. It has the effect that can be.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of the present invention.

FIG. 2 is a perspective view showing a state of a substrate after removing an optical fiber with a filter and an optical element from FIG. 1;

FIG. 3 is a front view showing a second embodiment of the present invention.

FIG. 4 is a front view showing a third embodiment of the present invention.

FIG. 5 is a front view showing a fourth embodiment of the present invention.

FIG. 6 is a front view showing a fifth embodiment of the present invention.

FIG. 7 is a front view showing a sixth embodiment of the present invention.

FIG. 8 is a perspective view showing a conventional optical multiplexer / demultiplexer.

[Explanation of symbols]

 Reference Signs List 10 substrate 11 narrow groove 12 wide groove 14 wide groove 16 V groove 18 engraving 20 multiplexing / demultiplexing filter 31A optical waveguide 31B optical waveguide 32 optical waveguide 33 optical waveguide 50 light emitting element 50A light emitting element 51 light emitting end 60 light receiving element 60A light receiving element Reference Signs List 61 light receiving end 70A optical fiber 70B optical fiber 80 optical fiber with filter 81 multiplexing / demultiplexing filter film 82 cut filter film 83 half mirror film 85 core

Claims (9)

[Claims] An optical wavelength multiplexer / demultiplexer for demultiplexing or multiplexing light of a plurality of wavelengths, wherein a light of a first wavelength is transmitted to one end and a light of a second wavelength is reflected. One end of the optical fiber (80) on which the demultiplexing filter film (81) is formed, and one end face of the optical fiber (80) on which the multiplexing / demultiplexing filter film (81) is formed and intersect at the end surface An optical wavelength multiplexer / demultiplexer comprising two optical waveguides (31A, 31B). 2. An optical wavelength multiplexer / demultiplexer for demultiplexing or multiplexing light of a plurality of wavelengths, wherein one end face is formed obliquely with respect to the axial direction, and a multiplex / demultiplex filter film (81) is formed on the end face. ) Formed optical fiber (8
0) The end face faces the side face of one end of the optical fiber (80), and its axis is symmetric with respect to the axis of the optical fiber with respect to the surface normal of the multiplexing / demultiplexing filter film (81). An optical wavelength multiplexer / demultiplexer, comprising: an optical waveguide (33) installed so as to be able to form an optical waveguide. 3. The optical wavelength multiplexer / demultiplexer according to claim 1, wherein a semi-transmission filter is provided at another end different from said one end, the end being inclined with respect to the axial direction. An optical fiber (80) on which a film (83) is formed, an end face of which faces the side surface of the other end of the optical fiber (80), and an axis of which faces the surface normal of the translucent filter film (83) An optical wavelength multiplexer / demultiplexer comprising an optical waveguide (34) installed so as to be symmetric with respect to the axis of the optical fiber. 4. The optical wavelength multiplexer / demultiplexer according to claim 2, wherein said optical waveguide (33) is a multi-mode waveguide. 5. An optical wavelength multiplexer / demultiplexer according to claim 1, wherein said optical fiber is a multimode fiber or a TEC fiber. 6. The optical wavelength multiplexer / demultiplexer according to claim 1, wherein the optical waveguides (31A, 31B, 33) and the V-groove (16) for installing the optical fiber (80) are provided. An optical wavelength multiplexer / demultiplexer having a substrate (10) integrally formed on one surface, wherein the optical fiber (80) is provided on the V-groove (16). 7. The optical wavelength multiplexer / demultiplexer according to claim 6, wherein said substrate is made of silicon, and said V-groove is formed by anisotropic etching. Optical wavelength multiplexer / demultiplexer. 8. The optical wavelength multiplexer / demultiplexer according to claim 7, wherein the optical waveguides (31A, 31B, 33) and the V-groove (1) are provided.
6. An optical wavelength multiplexer / demultiplexer, wherein grooves (12, 14) are provided at the boundary with (6). 9. An optical wavelength multiplexer / demultiplexer according to claim 7, wherein the optical waveguides (31A, 31B, 33, 34) are polymer optical waveguides.