JP2000241657A - Optical waveguide unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide inexpensive optical waveguide unit capable of coupling easily a multiple optical fiber with an optical element array at a high density and a low loss. SOLUTION: This optical waveguide unit is provided with an optical waveguide member 31 having a core part 32 carrying out light transmission and a clad part 33 surrounding the core part 32 with a refrative index lower than that of the core part 32, a connecting block 40 forming a fiber attaching hole 41 into which an optical fiber coupled to the waveguide member 31 is inserted from its one end, and a presser glass 44 for connecting a base end part of the waveguide 31 to the other end part of the block 40 to make the center of the core part 32 of the waveguide 31 coincident with the center of the hole 41. The fiber attaching hole 41 has a straight line part of a fixed inner diameter corresponding to an outer diameter of the optical fiber, and a tapered part 42 tapered from the straight line part toward at least an opening end of the one end to increase its inner diameter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical waveguide unit for connecting an optical element and an optical fiber.

[0002]

2. Description of the Related Art In recent years, in the field of high-speed and large-capacity communication,
Research and development of optical interconnection technology based on parallel optical transmission has been actively conducted. In particular, a surface emitting laser (hereinafter referred to as V
In a module for optical interconnection using an optical element array in which surface-receiving photodiodes are integrated in an array, an optical interconnection module is used to connect the optical element array to an optical fiber as a transmission path. Optical components are required.

In parallel optical interconnection, a coated optical fiber core having an outer diameter of 250 μm
Since multi-core optical fibers bundled in a tape at μm intervals are used as transmission lines, this multi-core optical fiber
An important issue is how to easily connect an optical element array having functions such as light receiving, branching, multiplexing, switching, and modulation with high density and low loss and easily.

As an example of the above-mentioned optical component for connecting an optical element array and a multi-core optical fiber, a bare optical fiber whose coating has been removed is inserted into a micro ferrule,
PC using the buckling force of the optical fiber as a pressing force (P hysi
The optical connector cal C ontact) structure (Japanese Patent Application No. 6-15234
No. 9) and an optical waveguide unit (see Japanese Patent Application No. 9-198235) connectable to the plug of the optical connector.

[0005] In this specification the optical connector of the above-mentioned PC structure is referred to as BF (B are F iber) connector. FIG. 7 shows a state before connection of such a BF connector, and FIG. 8 shows a structure after connection. This BF connector has a first optical fiber 1 having an outer diameter of 125 μm with the coating removed.
1 comprises a plug 12 arranged in an aligned state and a receptacle 14 in which a micro ferrule 13 to be paired with the plug 12 is arranged in an aligned state.
The first optical fiber 11 has a fiber mounting hole 15 having an inner diameter slightly larger than the outer diameter of the first optical fiber 11.
The connection end of the second optical fiber 16 having the same outer diameter as that of the second optical fiber 16 is integrally fitted to one end of the fiber mounting hole 16. Then, by inserting the plug 12 into the receptacle 14, the first optical fiber 11 is inserted into the fiber mounting hole 16 of the micro ferrule 13, and the second optical fiber 16 fixed in the fiber mounting hole 16 is connected to the first optical fiber 11. Aligned concentrically. The buckling force generated by excessively pushing the first optical fiber 11 into the fiber mounting hole 16 is used as a pressing force, and the connection end faces 17, 18 of the optical fibers 11, 16 are brought into the PC state with a slight load. Keep
These can be connected with low loss.

In this optical fiber connection structure, optical fibers can be connected at a narrow pitch of about the outer diameter of the optical fiber, and a receptacle 14 having an insertion guide mechanism such as a micro ferrule 13 is used. In addition, the arrangement pitch accuracy of the optical fibers 11, 16 and the receptacle 14 can be reduced, and a super multi-core optical connector can be easily realized. Therefore, it can be said that this is an extremely effective connection method in an optical interconnection in which many sets of optical fibers need to be connected.

The above-mentioned receptacle 14 of the BF connector
FIG. 9 shows an external view of an optical waveguide unit disclosed in Japanese Patent Application No. 9-198235, which is an alternative to Japanese Patent Application No. Hei 9-198235.
Shown in In other words, this optical waveguide unit is an optical element 1
An optical waveguide member 22 having a reflection surface 341 inclined at 45 degrees with respect to the longitudinal direction of the core portion 20 for transmitting and receiving signals to and from the optical waveguide member 9 at the distal end side, and a base end of the optical waveguide member 22 A connection block 24 integrally joined through a fixing holding plate 23, and a V-groove (not shown) is formed in the connection block 24 at an equal interval to the optical fiber 11 on the plug 12 side. Here, micro ferrules 13 each having a fiber mounting hole 15 having an inner diameter slightly larger than the outer diameter of the optical fiber 11 are mounted. On one end side (on the optical waveguide member 22 side) of these micro ferrules 13, a connection optical fiber 25 abutting on the base end surface of the optical waveguide member 22 is mounted in advance, and the plug 12 is inserted from the other end side of these micro ferrules 13. By inserting the optical fiber 11, the optical waveguide unit can be connected to the plug 12 of the BF connector.

[0008]

The conventional BF connector as shown in FIGS. 7 and 8, and the conventional optical waveguide unit as shown in FIGS.
It is necessary to use a connection part whose inside diameter dimension is processed with high precision, such as the micro ferrule 13 for guiding the micro ferrule, and the same number of optical fibers 11 as the micro ferrule 13 to be connected must be prepared. In addition, there is a problem that the number of parts increases and the assembly process becomes complicated.

In addition, the manufacturing cost of the micro ferrule 13 itself is high, and the manufacturing cost of the entire optical waveguide unit is increased.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide an inexpensive optical waveguide unit capable of easily connecting a multi-core optical fiber and an optical element array with high density and low loss.

[0011]

SUMMARY OF THE INVENTION An optical waveguide unit according to the present invention comprises an optical waveguide member having a core for transmitting light and a cladding surrounding the core and having a lower refractive index than the core. A connection block formed with a fiber mounting hole into which an optical fiber to be connected to the optical waveguide member is inserted from one end side; and fixing means for connecting the base end of the optical waveguide member to the other end side of the connection block. Wherein the fiber mounting hole has a linear portion with a constant inner diameter corresponding to the outer diameter of the optical fiber, and the inner diameter increases from the linear portion toward at least the open end on one end side. And the fixing means connects the optical waveguide member to the connection block such that the center of the core portion of the optical waveguide member coincides with the center of the fiber mounting hole. And it is characterized in that it is.

According to the present invention, when inserting the tip of the optical fiber into the fiber mounting hole formed in the connecting block,
Even if these positions are slightly displaced, they are securely inserted by the tapered portion formed on one end side of the fiber mounting hole, so that they are connected to the core portion of the optical waveguide member. In this case, the center of the core portion of the optical waveguide member coincides with the center of the fiber mounting hole, and the optical signal between the core portion of the optical waveguide member and the optical fiber is kept in a state where the connection loss is minimized. The exchange is performed.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION In the optical waveguide unit according to the present invention, it is possible to further provide an optical transmission member which is housed at the other end side of the fiber mounting hole and abuts on the base end surface of the optical waveguide member. The optical transmission member may be an optical fiber or a rod lens. It is also possible to further provide a plate-shaped optical transmission member interposed between the opening end face on the other end side of the fiber mounting hole and the base end face of the optical waveguide member and abutting against them. The transmission member may have a rod lens. In any case, the tip of the optical fiber inserted into the fiber mounting hole does not directly contact the optical waveguide member, and an optical signal is transmitted and received via the optical transmission member.

The optical waveguide member may have a plurality of core portions and a plurality of fiber mounting holes. In this case, the optical waveguide member has
It may have a plate shape with a constant thickness. Further, the fixing means may have an attachment reference surface formed on the other end side of the connection block and on which the base end of the optical waveguide member is overlapped.

The connecting block may be a resin molded part made of a thermosetting epoxy resin or a liquid crystal polymer.

The materials constituting the optical waveguide include:
Organic substances such as inorganic glass (quartz, multi-component glass, etc.), semiconductors, and polymers can be used. For example,
Representative polymers include deuterated polymethyl methacrylate and ultraviolet (UV) curable epoxy resins, but are not limited to these materials.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the optical waveguide unit according to the present invention will be described in detail with reference to FIGS. 1 to 6, but the present invention is not limited to such an embodiment, and these may be further combined or similar. It can also be applied to technologies in other fields that include issues.

FIG. 1 shows an exploded structure of a first embodiment of the present invention, and FIG. 2 shows a sectional structure thereof. That is, the optical waveguide member 31 in the present embodiment has a rectangular plate shape, for example, deuterated polymethyl methacrylate (refractive index: 1.49).
0) and a plurality of (in the illustrated example, 24) core portions 32 and a cladding portion 33 made of an ultraviolet-curable epoxy resin (refractive index: 1.475) surrounding these core portions 32. And Naturally, the refractive index of the core portion 32 is higher than that of the clad portion 33, and the length of the optical waveguide member 31 in the present embodiment along the longitudinal direction of the core portion 32 is 13 mm. At the tip of the optical waveguide member 31, a reflection surface 34 inclined at 45 degrees with respect to the longitudinal direction of the core portion 32 is formed, and such an optical waveguide member 31 is formed, for example, by forming an inclined end face of a planar optical waveguide. It can be manufactured by a method (see Japanese Patent Application No. 8-202275). The cross-sectional dimension of the core portion 32 in this embodiment is 42 μm × 42 μm, and the bottom surface 3 of the optical waveguide member 31
The height from 5 to the center of the core 32 is 75 μm. The spacing between the adjacent core portions 32 is set to 250 μm in accordance with the spacing between individual VCSEL elements constituting two surface emitting lasers (hereinafter referred to as VCSELs) array 36 arranged to face the reflecting surface 34. Set to pitch. 12-channel VCSEL in this embodiment
The arrays 36 are spaced apart such that their center spacing is 10 mm.

The mounting reference surface 37 on which the base end of the optical waveguide member 31 is superimposed, and the base end surface 3 of the optical waveguide member 31
The connection block 40 formed with the joint end face 39 against which the abutment 8 is formed has a structure capable of connecting to a plug of a BF connector (not shown) in which two groups of 24 optical fibers are arranged at a pitch of 250 μm. In this embodiment, since two VCSEL arrays 36 of 12 channels are used,
Since it is necessary to match the arrangement pitch of the optical fibers of the F connector, 12 core portions 32 of the optical waveguide member 31 are provided.
The waveguide structure is divided into two sets, and is arranged so that they are bent so as to be further apart on the reflection surface 34 side.

The connection block 40 in this embodiment is a precision injection molded product of a resin such as a thermosetting epoxy resin or a liquid crystal polymer, and has an inner diameter of 126 μm slightly larger than 125 μm, which is the outer diameter of the optical fiber of the BF connector. Fiber mounting holes with a pitch of 250 μm
A total of 24 pairs are formed. The length of the fiber mounting hole 41 along the longitudinal direction is 4 mm, and one end of the fiber mounting hole 41 on the side into which the connector of the BF fiber is inserted is a tapered portion 42 whose inner diameter increases toward the opening end. ing. On the other end side (the optical waveguide member 31 side) of the fiber mounting hole 41, a protective optical fiber 43 as an optical transmission member of the present invention is accommodated. The protective optical fiber 43 has an outer dimension of 125 μm and 2 mm. Having a length of By mounting the protective optical fiber 43 in the fiber mounting hole 41, the tip of the optical fiber of the BF fiber inserted into the fiber mounting hole 41 does not directly contact the base end surface 38 of the optical waveguide member 31. Damage to the base end surface 38 of the member 31 can be prevented beforehand. The height from the mounting reference plane 37 formed in the connection block 40 to the center of the fiber mounting hole 41 is the same as the height of the core 32 of the optical waveguide member 31, ie, 75 μm.
m is set.

The base end of the above-mentioned optical waveguide member 31 is a plate-like holding glass 4 which forms a part of the fixing means of the present invention.
4, and is pressed against an attachment reference surface 37 of the connection block 40. These are UV-curable adhesives (not shown) such that the center of the core portion 32 of the optical waveguide member 31 and the center of the fiber mounting hole 41 match. And are integrally fixed. In this case, the optical waveguide member 31 and the connection block 40
Can be achieved only by placing the optical waveguide member 31 on the mounting reference surface 37. The alignment of the fiber mounting holes 41 along the arrangement direction can be easily performed by aligning the center of the protective optical fiber 43 with the center of the core 32 of the optical waveguide member 31 under a microscope. .

When manufacturing the optical waveguide unit according to the present embodiment, first, 24 protective optical fibers 43 are inserted into the fiber mounting holes 41 formed in the connecting block 40 and fixed by bonding. Compared to a structure using a conventional micro ferrule, the number of components is reduced to about half since the micro ferrule is not used, and the time required for assembling can be reduced to about 1/20. In addition, since the connection block 40 is a resin injection-molded product, it is suitable for mass production and its manufacturing cost can be significantly reduced.

In order to evaluate the optical characteristics of the optical waveguide unit according to the present embodiment, a coupling loss was measured when the VCSBL array 36 and a BF connector (not shown) were connected via this optical waveguide unit. Specifically, wavelength 0.8
The signal light emitted from the 12-channel VCSBL array 36 of the 5 μm band is made incident on the core portion 32 of the optical waveguide member 31 using the reflection surface 34 of the optical waveguide member 31, and the output light intensity from the optical fiber attached to the plug of the BF connector. Was measured. As a result, 1.7 ± 0.
It was 2 dB, and it was confirmed that the optical waveguide unit of this example had sufficiently low loss and uniform optical characteristics even when compared with the conventional optical waveguide unit.

In the embodiment described above, deuterated polymethyl methacrylate is used as the core 32 of the optical waveguide member 31, but other materials can be used as long as they have a higher light refractive index than the cladding 33.

FIG. 3 shows the appearance of such another embodiment of the present invention. Members having the same functions as those of the previous embodiment are denoted by the same reference numerals, and overlapping descriptions are omitted. I do.

That is, the core 32 of the optical waveguide member 31 of this embodiment is made of a UV-curable epoxy resin (refractive index: l.
5343), and the cladding part 33 is also made of a UV-curable epoxy resin (refractive index: 1.5138). It is expected that stable characteristics will be maintained. The length of the optical waveguide member 31 along the core portion 32 is 15 mm, and the core portion 32 in this embodiment has no bent portion and is formed linearly.

As a result of evaluating the optical characteristics of this optical waveguide unit in the same manner as in the previous embodiment, the coupling loss including the BF connector was 1.0 in all the channels. 0 ± 0.2
dB, and it was confirmed that the optical waveguide unit of this example had sufficiently low loss and uniform optical characteristics even when compared with the conventional optical waveguide unit.

In the above-described embodiment, the protective optical fiber 43 is fitted into each of the fiber mounting holes 41. However, a single flat optical transmission member may be used.

FIG. 4 shows a cross-sectional structure of another embodiment of such an optical waveguide unit according to the present invention. Members having the same functions as those of the previous embodiment are denoted by the same reference numerals, and are duplicated. Description is omitted. That is, a single transparent glass plate 45 of 0.25 mm is joined to the joint end surface 39 of the connection block 40, and the base end surface 38 of the optical waveguide member 31 is pressed against this glass plate 45. The fiber mounting hole 41 is hollow, into which the optical fiber of the BF connector is inserted, and the end of which is pressed against the glass plate 45. In the present embodiment, since it is not necessary to attach a protective optical fiber to each of the fiber mounting holes 41, it is particularly effective for an optical waveguide unit having a large number of channels, thereby reducing the number of parts and simplifying the manufacturing process. It can be further promoted.

As a result of evaluating the optical characteristics of this optical waveguide unit in the same manner as in the previous embodiment, the coupling loss including the BF connector was 1.0 in all the channels. 9 ± 0.2
dB, and it was confirmed that the optical waveguide unit of this example had sufficiently low loss and uniform optical characteristics even in comparison with the conventional optical waveguide unit.

In the above-described embodiment, the presence of the glass plate 45 causes the optical fiber and the optical waveguide member 3 on the BF connector side.
Since there is a tendency that the loss of the optical signal between the first core portion 32 and the core portion 32 tends to increase, the loss can be further reduced by incorporating a rod lens array having a light condensing function into the glass plate. .

FIG. 5 shows a cross-sectional structure of another embodiment of the present invention. Members having the same functions as those of the previous embodiment are denoted by the same reference numerals, and overlapping descriptions are omitted. Shall be. That is, a rod lens array 46 having a pitch of 250 μm and a diameter of 125 μm is integrally formed on a glass plate 45 having a thickness of 0.88 mm. The rod lens array 46 is a so-called micro selfoc lens array having a different refractive index along the radial direction, and two sets of twelve rod lens arrays are provided corresponding to the arrangement interval of the fiber mounting holes 41, for a total of 24 rod lens arrays. . Each rod lens constituting the rod lens array 46 is arranged such that its optical axis coincides with the center of the corresponding fiber mounting hole 41 and the center of the core 32 of the optical waveguide member 31, and the rod lens as a convex lens Fiber mounting hole 41 by optical function
The coupling efficiency of an optical signal between the optical fiber of the BF connector inserted into the optical waveguide member 31 and the core portion 32 of the optical waveguide member 31 can be increased.

In the same manner as in the previous embodiment, the glass plate 45 in which the rod lens array 46 is incorporated is such that the tip of the optical fiber of the BF connector contacts the core 32 of the optical waveguide member 31, and Problems such as damaging the joint end face are prevented beforehand.

As a result of evaluating the optical characteristics of this optical waveguide unit in the same manner as in the previous embodiment, the coupling loss including the BF connector is 1 l in all the channels. 8 ± 0.2
dB, and it was confirmed that the optical waveguide unit of this example had sufficiently low loss and uniform optical characteristics even in comparison with the conventional optical waveguide unit.

In each of the embodiments described above, the optical fiber of the BF connector and the base end face 38 of the optical waveguide member 31 are not directly contacted. However, the core of the optical waveguide member 31 is controlled by the optical fiber of the BF connector. If there is no risk that the coupling end face of the portion 32 will be damaged, the above-described optical transmission member can be omitted for the purpose of reducing the number of components.

FIG. 6 shows a cross-sectional structure of another embodiment of the present invention. Members having the same functions as those of the previous embodiment are denoted by the same reference numerals, and overlapping description is omitted. Shall be. That is, the base end surface 38 of the optical waveguide member 31 is directly in contact with the other end of the fiber mounting hole 41 having the tapered portion 42 whose inner diameter increases toward the open end at one end. Each core part 32 of the member 31
Is the same as the center of the fiber mounting hole 41 as in the previous embodiment.

In the optical waveguide unit of this embodiment, since the optical waveguide member 31 and the optical fiber of the BF connector can be directly connected, the transmission loss due to the use of the optical transmission member can be eliminated. It has low loss and uniform optical characteristics as in the embodiment.

[0038]

According to the optical waveguide unit of the present invention, B
A fiber mounting hole into which the optical fiber on the plug side of the F connector is directly inserted is formed in the connection block, eliminating the need to use a conventional micro ferrule, greatly reducing the number of parts and the assembly process. It can be greatly simplified.

In the case where an optical transmission member is provided in contact with the base end face of the optical waveguide member, it is possible to avoid damage to the connection end face of the optical waveguide when inserting the optical fiber. In particular, when an optical fiber or a rod lens is used as the optical transmission member, the connection loss can be minimized.

Further, in the case where an attachment reference plane for superposing the optical waveguide member on the connecting block is provided as a fixing means, the center of the core portion of the optical waveguide member and the center of the fiber mounting hole can be easily matched. And the workability can be greatly simplified. Moreover, when the connecting block is formed of a resin molded part suitable for mass production, the manufacturing unit price can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an appearance of an embodiment of an optical waveguide unit according to the present invention.

FIG. 2 is a sectional view showing a schematic structure of the embodiment shown in FIG.

FIG. 3 is a perspective view illustrating an appearance of another embodiment of the optical waveguide unit according to the present invention.

FIG. 4 is a sectional view showing a schematic structure of another embodiment of the optical waveguide unit according to the present invention.

FIG. 5 is a sectional view showing a schematic structure of still another embodiment of the optical waveguide unit according to the present invention.

FIG. 6 is a sectional view showing a schematic structure of still another embodiment of the optical waveguide unit according to the present invention.

FIG. 7 is a principle diagram showing a schematic structure of a conventional BF connector together with FIG. 8, showing a state before connection.

8 is a principle diagram showing a schematic structure of a conventional BF connector together with FIG. 7, and shows a state after connection.

FIG. 9 is a perspective view illustrating an appearance of a conventional optical waveguide unit.

10 is a sectional view illustrating a schematic structure of the optical waveguide unit illustrated in FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 31 optical waveguide member 32 core portion 33 clad portion 34 reflecting surface 35 bottom surface 36 VCSEL array 37 mounting reference surface 38 base end surface 39 bonding end surface 40 connecting block 41 fiber mounting hole 42 taper portion 43 protective optical fiber 44 holding glass 45 glass plate 46 Rod lens array

Continued on the front page (72) Inventor Akira Ogi 3-192-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Inventor Nobuaki Matsuura 3- 19-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Nippon Telegraph and Telephone Telephone Co., Ltd. (72) Inventor Michiyuki Amano 3-192-2 Nishishinjuku, Shinjuku-ku, Tokyo Japan Telegraph and Telephone Co., Ltd. (72) Inventor Shunichi Higashino 3-192-2, Nishishinjuku, Shinjuku-ku, Tokyo Japan Within Telegraph and Telephone Co., Ltd. (72) Inventor Koji Enbu 3-19-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Japan Within Telegraph and Telephone Co., Ltd. (72) Makoto Hikita 3-2-1, Nishi-Shinjuku, Shinjuku-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Kosuke Katsura Inventor 3--19-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Inventor Yasuhiro Ando 3-192, Nishi-Shinjuku, Shinjuku-ku, Tokyo Nippon Telegraph and Telephone Corporation F-term (reference) 2H037 AA01 BA04 BA06 BA13 BA14 BA23 BA24 CA39 DA14

Claims (10)

[Claims] 1. An optical waveguide member having a core portion for transmitting light, a cladding portion surrounding the core portion and having a lower refractive index than the core portion, and an optical fiber connected to the optical waveguide member. An optical waveguide unit comprising: a connection block formed with a fiber mounting hole to be inserted from one end side; and fixing means for connecting a base end of the optical waveguide member to the other end side of the connection block, The fiber mounting hole has a linear portion having a constant inner diameter corresponding to the outer diameter of the optical fiber, and a tapered portion having an inner diameter that increases from the linear portion toward at least the open end on one end side. An optical waveguide unit, wherein the optical waveguide member is connected to the connection block such that the center of the core portion of the optical waveguide member coincides with the center of the fiber mounting hole. 2. The optical waveguide unit according to claim 1, further comprising an optical transmission member housed at the other end side of said fiber mounting hole and abutting on a base end surface of said optical waveguide member. 3. The optical waveguide unit according to claim 2, wherein said optical transmission member is an optical fiber. 4. The optical waveguide unit according to claim 2, wherein said optical transmission member is a rod lens. 5. The optical transmission device according to claim 1, further comprising a plate-shaped optical transmission member interposed between the opening end surface on the other end side of the fiber mounting hole and the base end surface of the optical waveguide member and abutting against them. The optical waveguide unit according to claim 1. 6. The optical waveguide unit according to claim 5, wherein said optical transmission member has a rod lens. 7. The optical waveguide member according to claim 1, further comprising a plurality of said core portions and said fiber mounting holes.
The optical waveguide unit according to any one of claims 1 to 6. 8. The optical waveguide unit according to claim 7, wherein the optical waveguide member has a plate shape with a constant thickness. 9. The fixing device according to claim 8, wherein the fixing means has an attachment reference surface formed on the other end side of the connection block and on which the base end portion of the optical waveguide member is overlapped. Optical waveguide unit. 10. The optical waveguide unit according to claim 1, wherein the connection block is a resin molded part.