JP2719353B2 - Multi-core optical terminal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an optical waveguide component which is capable of connecting a plurality of substrate-type optical waveguide components to a multi-core optical fiber at a time with low loss and detachable. -It relates to a multi-core optical terminal for optical fiber coupling.

<Prior art and its problems> Functional elements such as an optical integrated circuit and a waveguide type optical element are indispensable for enhancing the functionality of an optical transmission network. Since the input / output section of these high-density integrated elements is composed of multiple arrayed elements or multiple optical waveguides, it is desired to realize a multi-terminal collective connection technology with a multi-core optical fiber. ing.

Conventionally, as shown in FIG. 8, the connection between the optical waveguide and the multi-core optical fiber is such that the optical fiber 101 is fixed to a substrate 102 having multiple V-grooves, and the substrate 102 and the optical waveguide 103 are axially aligned. It has been performed by a method of fixing the fiber alignment substrate 102 and the optical waveguide substrate 104 with an adhesive or the like. However, in this method, the multi-core optical fiber and the optical waveguide component are aligned using a precision fine adjustment table or the like, and the alignment is maintained by fixing the multi-core optical fiber and the optical waveguide component. Absent. For this reason, there were the following problems.

In the method in which the waveguide element and the optical fiber array are fixed by directly applying an adhesive, a problem at the time of manufacturing is that when assembly or bonding at the joint fails, the ends of the waveguide element and the optical fiber array are damaged. Both become useless and cannot be regenerated due to the adhesion of the adhesive. This leads to poor manufacturing yield.

As a problem in mounting on a device or the like, there is a problem that since an optical fiber is bonded and fixed to both ends of the input and output of the element, a mounting method is limited and a mounting density cannot be increased. In an actual device, an extra length is provided to enable reconnection of input / output fibers, so that it is not easy to increase the mounting density.

As a maintenance problem, since the waveguide element and the optical fiber array are integrated, the only way to separate them is to destroy them. Therefore, (1) when the optical fiber is broken, both the element and the optical fiber become useless.
(2) Even in the event of a failure of the device, it becomes useless including the joint between the optical fiber and the device. In both (1) and (2), it is necessary to replace an element with an optical fiber and to redo wiring and the like in the apparatus, so that maintenance efficiency is low. As described above, there are problems in control yield, mounting density, and maintenance efficiency.

On the other hand, a conventional multi-fiber optical fiber connection switching method includes a multi-fiber optical fiber connector shown in FIGS. 9 (a) and 9 (b). As shown in FIG.
Is fixed to the connector plug 112 via the boot 111. The connector plug 112 is provided with a guide pin 113, and when the pair of connector plugs 112, 112 are inserted into the rectangular sleeve 114 so as to abut each other, the guide pin 113 is fitted as a guide, and both the optical fibers 110a, 110a are pivoted. Connected together. At the time of connection, it is stably held by the leaf springs 115,115. This connector can connect and disconnect multi-core single mode optical fiber with low loss of about 0.4dB on average. However, in order to couple the optical fiber and the optical waveguide component with low loss and to make it removable, it is necessary to provide a detachable fitting means on the optical waveguide component side. No proposal has been made to answer these requests.

The object of the present invention is to solve the problem that the connection between the multi-strip optical waveguide component and the multi-core optical fiber was not permanent because the connection portion was conventionally permanently connected. An object of the present invention is to realize a stable connection in which a multi-core optical fiber can be detached.

<Means for Solving the Problems> In the multi-core optical terminal of the present invention, since the guide holes and the optical fibers are arranged with high precision at both end faces, the multi-core optical terminal of the present invention is connected to the optical waveguide substrate and the shaft. It is characterized in that a multi-core optical fiber connector can be connected to the optical waveguide substrate with low loss and can be attached and detached simply by bonding and fixing.

In the prior art, the optical waveguide component and the optical fiber are directly aligned with each other and bonded and fixed.

<Embodiment> FIG. 1 is a view for explaining a first embodiment of a multicore optical terminal according to the present invention, wherein 1 is an optical fiber, 2 is a guide hole, and the material of the body 3 is quartz glass powder. Of an epoxy compound containing about 70% by weight. The positional accuracy of the arrangement of the guide hole 2 of the multi-core optical terminal and the fiber 1 is made highly accurate within 1 μm. Epoxy body material is suitable for precision molding because of its small molding shrinkage and thermal expansion coefficient.

FIG. 2 is a perspective view for explaining an application example of the first embodiment of the present invention, wherein 4 is a multi-layer waveguide substrate, 5 is an optical waveguide embedded in the multi-layer optical waveguide substrate 4, and 6 is The base is a transparent quartz plate, 7 is a guide pin, 8 is a multi-core optical terminal according to the present invention, 9 is an adhesive, and the multi-strip optical waveguide substrate 4 is a base 6
Is bonded and fixed with a transparent thermosetting epoxy adhesive (not shown). After the optical axes of both the optical fiber 1 and the optical waveguide 5 included in the multi-core optical terminal 8 are aligned, the multi-core optical terminal 8 is connected to both the base 6 and the multi-strip optical waveguide substrate 4. Temporarily fixed with UV-curable transparent epoxy adhesive,
Permanently fixed with thermosetting epoxy adhesive. The multi-core optical fiber connector 10 and the multi-core optical terminal 8 are connected via a guide pin 7. Since the guide pin 7 can be freely inserted and removed, the connecting portion can be repeatedly attached and detached easily. Since the positional accuracy of the arrangement of the guide pins 7 at both ends of the multi-core optical terminal 8 and the optical fiber 1 is made within 1 μm, it can be connected to the multi-core optical fiber connector 10 via the guide pins 7 at one end with low loss. The other end face can also be coupled to the multiple optical waveguides 5 arranged with high precision with low loss.

As a multi-core optical fiber, a 10-core ribbon core coated with 10 single-mode fibers having a mode field diameter of about 10 μm at a wavelength of 1.3 μm is used. The core of the waveguide is a silica-based material with a core cross-section of 10 μm. The coupling loss between the two was measured using an optical waveguide having a rectangular shape of × 10 μm and a relative refractive index difference of about 2.5%. The coupling loss measurement was performed on eight cores of the ten optical fibers excluding the two cores at both ends. as a result,
The coupling loss value in the form of a waveguide: a multi-core optical terminal: a multi-core optical fiber connector was about 1 dB on average for eight cores. Of these, the coupling loss of a multi-core optical terminal: a multi-core optical connector was approximately 0.2dB
Met. Further, when the connection and detachment of the connection portion of the multi-core optical terminal ... multi-core optical connector were repeated, the variation of the coupling loss was about 0.1 dB in 10 repetitions. The distance between the pin centers of the multi-core optical fiber connector 10 shown in FIG. 2 was 4.6 mm.
The width x thickness x length of the multi-core optical fiber connector 10 is 6.
4mm × 2.5mm × 8mm, multi-core optical terminal 8 is 6.4mm × 2.5mm × 4mm
It was made small. The reason for the miniaturization is that the structure of the coupling portion between the multi-core optical terminal 8 and the multi-core optical fiber connector 10 using the guide pins 7 is simple, and the multi-core optical terminal 8 and the optical waveguide 5
This is due to the simplicity of the axis alignment method.

In FIGS. 3, 4 and 5 described below,
Although the number of fiber cores, the fiber fixing V-groove, and the fiber insertion hole are illustrated as four cores for simplicity, the actual number is eight.

Next, a method for manufacturing the multi-core optical terminal 8 of the present invention will be described.
The first method is to insert-mold the fiber directly into plastic. FIG. 3 shows a plastic molding die 13 provided with a plurality of V-shaped grooves 12 on both sides for aligning and positioning the guide pin molding die pin 11 and the optical fiber 1, and a lid of the die 13. 14 is shown. To mold the multi-core optical terminal 8, the mold pin 11 and the optical fiber 1 are sandwiched between a mold 13 having a multi-strip V-groove and its lid 15, and transfer molding is performed through a hole 15 on the lid 14. The epoxy compound as a raw material is filled in the cavity 16 by insert molding, and the mold pin 11 and the optical fiber 1 are insert-molded.
After the molded product is removed from the mold and the mold pin 11 is removed, it becomes a multi-core optical terminal as shown in FIG. 1 and is completed by polishing the end face of the optical fiber 1.

In a second manufacturing method, a hole-formed part 23 shown in FIG. 4 having a small-diameter optical fiber insertion hole 17 for inserting a fiber and fixing with an adhesive is formed in advance, and then the optical fiber is connected to the optical fiber. It is manufactured by inserting it into the insertion hole 17 and bonding and fixing it. This part 23 has a fiber insertion hole
17 and the guide hole 2 are arranged with high precision at both ends, a hollow 18 is provided at the center, and a groove 19 having a semi-circular cross section is provided following the hole fiber insertion hole 17. This hollow 18
By injecting the adhesive into the optical fiber insertion hole 17, the adhesive can be penetrated into the optical fiber insertion hole 17 and the optical fiber can be inserted into the optical fiber insertion hole 17 without entrapping air bubbles at the interface between the optical fiber and the optical fiber insertion hole 17. Can be fixed firmly.

FIG. 5 shows a mold 20 for molding a multi-core optical terminal having an optical fiber insertion hole. Reference numeral 21 denotes a pin for forming a fiber insertion hole. The optical fiber insertion hole 17 of the perforated part is
21 is formed by extracting. The pin 21 for forming the optical fiber insertion hole has a small outer diameter of 0.127 mm and is easily bent, so it is difficult to maintain the straightness only by supporting the multiple V-shaped grooves 12 on both sides. By adding 22, the bending of the pin is suppressed and the straightness of the pin 21 for forming the optical fiber insertion hole is increased. The support V-groove 22 forms a hollow 18 of the part 23 shown in FIG.

FIG. 6 shows a second embodiment of the present invention, in which a bent multi-core optical terminal 24 is shown. The optical fiber 1 is insert-molded in a resin while being bent at a right angle. When one end face is coupled with the waveguide, the other vertical terminal
The multi-fiber optical fiber connector can be raised vertically from the waveguide.

FIG. 7 shows a third embodiment of the present invention, in which a multi-core terminal 25 of a fiber arrangement pitch conversion type is shown. In the end face A in the figure, the arrangement pitch of the optical fibers 1 is 250 μm, and the optical fiber 1 is connected to the multi-core optical fiber connector 10 in FIG. At the end face B, the optical fibers 1 are closely arranged at a pitch of 125 μm and are coupled to the waveguide. The optical fiber in the core coating has a mechanical stability against external force such as bending since the coating serving as a buffer layer surrounds the optical fiber, but the pitch of the optical fiber is wide. on the other hand,
Since the optical waveguide tends to increase the loss at the bent portion, a sharp bend cannot be provided, and the substrate tends to be large. Since the cross-sectional dimension of the waveguide is as small as 10 μm in width and 10 μm in thickness, the pitch can be narrowed to reduce the size of the array pattern on the substrate in order to reduce the size of the substrate.

<Effects of the Invention> As described above, by using the multi-core optical terminal according to the present invention, the multi-strand optical waveguide substrate and the multi-core optical fiber connector can be connected with low loss, and the attachment / detachment characteristics thereof become stable. Since the waveguide can be handled as a module, the manufacturing yield, the mounting density of the waveguide substrate in the optical transmission device, and the efficiency of maintenance can be increased. Further, since the output of the waveguide substrate can be directed to a direction other than the plane parallel to the substrate, the degree of freedom of wiring of the waveguide element can be increased. As described above, by applying the multi-core optical terminal of the present invention to the connection between the waveguide and the multi-core fiber, an excellent effect that has not been achieved in the past can be obtained, which contributes to the practical use of the optical communication system. is there.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a multi-core optical terminal according to a first embodiment of the present invention, FIG. 2 is a perspective view showing an application example of the first embodiment,
FIG. 3 is a perspective view showing a mold for molding a multi-core optical terminal, and FIG.
FIG. 5 is a perspective view showing a perforated part for assembling a multi-core optical terminal, FIG. 5 is a perspective view showing a mold for molding the perforated part, and FIG. 6 is a bend according to a second embodiment of the present invention. FIG. 7 is a perspective view showing a multi-core optical terminal of a fiber arrangement pitch conversion type according to a third embodiment of the present invention, and FIG.
FIGS. 9A and 9B are perspective views showing a conventional connecting portion for coupling a waveguide and a multi-core optical fiber, and FIGS. 9A and 9B are perspective views showing a conventional technique for connecting multi-core optical fibers. In the drawings, 1 ... optical fiber, 2 ... guide hole, 3 ... body, 4 ... multi-strip optical waveguide substrate, 5 ... optical waveguide, 6 ... base, 7 ... guide pin, 8 ... multiple Core optical terminal, 9 ... Adhesive, 10 ... Multi-core optical fiber connector, 11 ... Mold pin, 12 ... V groove, 13 ... Mold, 14 ... Lid, 15 ... Hole, 16 ... ... cavity, 17 ... optical fiber insertion hole, 18 ... hollow, 19 ... groove, 21 ... pin, 22 ... support V groove, 24, 25 ... multi-core optical terminal, 101 ... optical fiber, 102 …… Substrate, 103 …… Optical waveguide, 104 …… Optical waveguide board, 110 …… Optical fiber tape, 111 …… Boot, 112 …… Connector plug, 113 …… Guide pin, 114 …… Rectangular sleeve, 115… Leaf spring.

Continuation of the front page (56) References JP-A-58-11109 (JP, A) JP-A-60-200210 (JP, A) JP-A-55-9959 (JP, A) JP-A-55-100514 (JP, A) , A)

Claims (1)

(57) [Claims] 1. A multi-core optical terminal which is inserted between a multi-strand optical waveguide substrate and a multi-core optical fiber connector to enable simultaneous connection and detachment of the multi-core optical fiber connector. An epoxy compound containing powder, a multi-core optical terminal is embedded in the multi-core optical terminal, and two guide holes for inserting guide pins are formed in the multi-core optical terminal. The position arrangement of the multi-core optical fiber and the two guide holes on the output end face coincides with the position arrangement of the optical waveguide or the optical fiber and the guide pin on the end face of the multi-strand optical waveguide substrate and the end face of the multi-core optical fiber connector, respectively. A multi-core optical terminal, wherein one of the multi-core optical terminals is permanently fixed to the multi-strip optical waveguide substrate with an epoxy adhesive.