JP2005309009A - Ferrule for multicore/multistep optical connector and multicore/multistep optical connector using same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve such a problem that it is difficult to insert an optical fiber into the upper step of fine pores for optical fiber insertion in a ferrule for multicore/multistep optical connector in which a plurality of fine pores for optical fiber insertion are constituted so as to be arranged laterally in a line and are laminated in a plurality of steps. <P>SOLUTION: When the angle between the line connecting the center on (j)th fine pore for optical fiber insertion of the guide groove side for optical fiber insertion, numbered from the lower side and the upper part of inlet of optical fiber insertion port and the axial line of fine pore for optical fiber insertion is α(j) and the length of guide groove for optical fiber insertion of (j)th numbered from the lower side is L(j), the following relation is satisfied: L(j)≥k×α(j)<SP>-0.5</SP>(k=1) and 0.3mm≤L(j)≤1.0mm. Thereby, even when optical fiber insertion angle α is reduced, the length L(j) of guide groove for optical fiber insertion increases and, therefore, the optical fiber can be easily inserted into the fine pore for optical fiber insertion. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a ferrule for a multi-core multi-stage optical connector and a multi-core multi-stage optical connector using the same.

  As a multi-fiber optical connector for connecting a plurality of optical fibers in a lump, a plurality of optical fiber insertion micro holes are arranged in one horizontal row at one end and one optical fiber communicated with each of the optical fiber insertion micro holes at the other end A multi-core optical fiber connector in which an insertion port is formed has been put into practical use. In recent years, as a higher-density multi-fiber optical connector, a structure in which a plurality of micro-insertion hole groups in which the plurality of optical fiber insertion micro-holes are arranged in a horizontal row is stacked in a plurality of stages has been proposed. (For example, Patent Document 1)

  10 and 11 show a ferrule for a multi-core multi-stage MT (Mechanically Transferable) optical connector disclosed in Patent Document 1, FIG. 10 is a sectional view, and FIG. 11 is a perspective view. . That is, in FIG. 10 and FIG. 11, the one end 11 of the multi-core multi-stage optical connector ferrule 10 is formed with a group of micro insertion holes 13 formed by arranging a plurality of optical fiber insertion micro holes 12 in a horizontal row, The fine insertion hole group 13 is formed in a plurality of stages. At the other end 16 of the ferrule 10 for a multi-core multi-stage optical connector, one optical fiber insertion port 17 communicating with each optical fiber insertion microhole 12 is formed. Further, in order to facilitate the insertion of the optical fiber 20 between each optical fiber insertion hole 12 and the optical fiber insertion port 17 of each micro insertion hole group 13, light communicated with each optical fiber insertion microhole 12. A fiber insertion guide groove 18 is formed.

  Further, an adhesive injection hole 19 communicating with the optical fiber insertion port 17 and the optical fiber insertion guide groove 18 is formed on the upper side of the ferrule 10 for the multi-fiber multi-stage optical connector. In the figure, reference numeral 15 denotes a shaft coupling hole for optical fiber insertion fine holes, which are formed on both sides of the multi-fiber multi-stage optical connector ferrule 10 respectively, and the connection end faces of the pair of multi-fiber multi-stage optical connector ferrules 10 are mutually connected. At the time of abutment, fitting pins (not shown) are inserted into each other to align the optical fiber insertion microholes 12 between the ferrules 10 for the multi-core multi-stage optical connector.

  The length of the optical fiber insertion guide groove 18 is generally selected from 0.3 mm to 1.0 mm, and is selected to be the same length in all stages. When inserting the optical fiber 20 into each of the optical fiber insertion micro-holes 12, as shown in FIG. 5, first, the optical fiber 20 is inclined obliquely with respect to the optical fiber insertion guide groove 18 to insert the optical fiber. Insert while pressing against the guide groove 18 in the P direction. In the present invention, the optical fiber insertion angle α at this time is called an optical fiber insertion angle. This optical fiber insertion angle α is, as shown in FIG. 3, a straight line connecting the center of the optical fiber insertion microhole on the optical fiber insertion guide groove side and the upper part of the entrance of the optical fiber insertion port, and the optical fiber insertion micro It is defined as the angle formed with the hole axis.

  When the optical fiber 20 is inserted along the optical fiber insertion guide groove 18 while being pressed against the bottom of the optical fiber insertion guide groove 18, the optical fiber insertion microhole 12 (or the optical fiber insertion microhole) is inserted. 12 and the optical fiber insertion guide groove 18) so that the optical fiber 20 can be inserted into the optical fiber insertion microhole 12 formed to have substantially the same diameter as the optical fiber 20. It has become. When the optical fiber 20 is inserted into the optical fiber insertion micro-hole 12, as shown in FIG. After inserting one stage, the optical fiber 20 is inserted into the next upper stage as shown in FIG. Thus, as shown in FIG. 8, the optical fiber 20 is inserted into the optical fiber insertion microholes 12 in all stages. Thereafter, an adhesive (not shown) is injected from the adhesive injection hole 19 into the ferrule 10 for the multi-fiber multi-stage optical connector and cured to mechanically fix the optical fiber 20 and the ferrule 10 for the multi-core multi-stage optical connector. .

  The assembly process of the optical connector includes the above-described adhesive curing process, and the adhesive is contracted by curing. Since the shrinkage causes distortion in the ferrule 10 for a multi-fiber multi-stage optical connector, it is not desirable to inject a large amount of adhesive. Therefore, the window of the adhesive injection hole 19 for injecting the adhesive of the optical connector needs to be configured not to be so large. The optical connector is formed by incorporating the multi-core multi-stage optical connector ferrule 10 assembled as described above into a frame housing.

  Although the length of the optical fiber insertion guide groove varies from 0.3 mm to 1.0 mm depending on the ferrule, the window shape of the adhesive injection hole 19 should not be so large as described above. In the case of one-stage multi-core, the optical fiber insertion guide groove 18 is 1.0 mm, in the case of two-stage multi-core, 0.5 mm, and in the case of multi-stage, the number of stages is 0.3 mm. As the number increases, the length of the optical fiber insertion guide groove 18 is set shorter.

JP 2003-241023 A

  In the multi-core multi-stage MT ferrule, an optical fiber is inserted from the group of the fine insertion holes at the bottom, and when the optical fiber has been inserted into the stage, the optical fiber is inserted into the optical fiber insertion hole of the next higher stage. As shown in FIG. 4, when the optical fiber is inserted into the lowest stage, the diameter of the optical fiber insertion port 17 is initially D as shown in FIG. The gap is reduced to D1. As the gap becomes smaller, the optical fiber insertion angle α for tilting the optical fiber becomes smaller, making it difficult to press the optical fiber against the optical fiber insertion guide groove 18. If the optical fiber 20 cannot be pressed well against the optical fiber insertion guide groove 18, the optical fiber is lifted from the optical fiber insertion guide groove 18 and cannot be inserted along the optical fiber insertion guide groove 18. Further, in the multi-core multi-stage ferrule, the number of stages is increased, but since the outer dimensions of the ferrule for the multi-core multi-stage optical connector are determined, the length of the optical fiber insertion guide groove in each stage is inevitably shortened. For this reason, the optical fiber insertion angle α for tilting the optical fiber cannot be made large, and it is difficult to press the optical fiber against the optical fiber insertion guide groove, and the optical fiber must be pressed against the short optical fiber insertion guide groove. It was difficult to insert an optical fiber.

  As an example, a case where an optical fiber is inserted with a four-stage ferrule will be described. When an optical fiber is inserted into the first stage or the second stage, the optical fiber insertion angle α is sufficient, and the insertion of the optical fiber is relatively easy. When the third stage is inserted, the optical fiber is already inserted in the lower two stages, and the gap D of the optical fiber insertion port is reduced. Therefore, it is difficult to insert the optical fiber at the third stage as shown in FIG.

  Further, as shown in FIG. 8, when the optical fiber is already inserted into the lower third stage when the optical fiber is inserted into the fourth stage, the gap between the optical fiber insertion ports is further smaller than when the optical fiber is inserted into the third stage. Thus, the optical fiber insertion angle α is further reduced. As a result, it is very difficult to insert the optical fiber because the optical fiber is caused to be along the optical fiber insertion guide groove in a state where the optical fiber insertion angle α cannot be secured large.

  If the work is performed in a state where the insertion of the optical fiber is difficult, it takes time to work and the cost of the connector is increased. Further, when inserting the optical fiber in the fourth stage, the operation is performed while touching the already inserted lower third stage optical fiber. The longer the working time, the longer the time for touching the optical fiber that has already been inserted. Further, even if the optical fiber is placed in the optical fiber insertion microhole 12, there is a possibility that the optical fiber may come out of the optical fiber insertion microhole 12 or the optical fiber may be disconnected. Increases, and the yield of the connector decreases.

  Since the outer shape of the MT ferrule is standardized, the size of the optical fiber insertion port is naturally limited. In a four-stage or five-stage multi-core ferrule, the optical fiber insertion port is already widened to the limit as long as the ferrule strength is maintained, so that the gap for inserting the optical fiber cannot be increased. Therefore, it is not easy to change the size of the gap of the optical fiber insertion port for inserting the optical fiber.

  Further, as shown in FIG. 9, it is conceivable that the optical fiber insertion angle is increased by bringing the optical fiber insertion guide groove 18 closer to the optical fiber insertion port 17. However, as disclosed in Patent Document 1, when the distance between the optical fiber insertion guide groove and the tape optical fiber is reduced, the bending of the optical fiber in the ferrule increases, leading to deterioration of characteristics (Patent Document 1). FIG. 13). Therefore, it is not preferable to bring the optical fiber insertion guide groove close to the optical fiber insertion port.

The present invention has been made in view of such points, and has focused on the relationship between the length of the optical fiber insertion guide groove and the optical fiber insertion angle. If the optical fiber insertion angle is small, the optical fiber insertion guide groove is better when the optical fiber insertion guide groove is long. FIG. 2 shows the experimental results regarding the relationship between the optical fiber insertion angle α and the length of the optical fiber insertion guide groove. The X-axis indicates the optical fiber insertion angle α, and the Y-axis indicates the length L of the optical fiber insertion guide groove. Plotted by square points are the experimental results, and show the relationship with respect to the optical fiber insertion angle α that is easy to insert with respect to the length L of the specific optical fiber insertion guide groove. The definition of the ease of insertion of an optical fiber is defined as the time spent for inserting a single tape optical fiber into one stage within one minute.
The approximate expression of the characteristic obtained from this experimental result is expressed by the following expression.
When the length of the optical fiber insertion guide groove is L and the optical fiber insertion angle is α, L = k · α ^−0.5 (k = constant 1).

  The length L of the optical fiber insertion guide groove is conventionally 0.3 mm to 1.0 mm, and if it is 0.3 mm or less, it is difficult to insert even if the optical fiber insertion angle α is large. The length L of the groove is desirably 0.3 mm or more.

  In addition, an optical fiber insertion experiment was performed with the length L of the optical fiber insertion guide groove being 1.0 mm or more. However, the insertion performance of the optical fiber was not different from that of 1.0 mm, and the optical fiber insertion guide groove was 1.0 mm or more. There is not much need to provide. In addition, if the length L of the optical fiber insertion guide groove is formed large, the adhesive injection hole becomes large in the multi-core multi-stage ferrule, so that the influence of the adhesive shrinkage described in the above problem is greatly affected. It is not desirable to provide an optical fiber insertion guide groove of 1.0 mm or more.

  The length L of the optical fiber insertion guide groove in the above approximate expression does not need to be connected with an equal sign between the left side and the right side with respect to a certain optical fiber insertion angle α, and the optical fiber insertion guide groove is calculated by an approximate expression. There is no problem if the number is larger than the number.

In consideration of these, the present invention is formed with a plurality of micro insertion hole groups each having a plurality of optical fiber insertion micro holes arranged in a horizontal row at one end, and the optical fiber insertion micro holes at the other end. One optical fiber insertion port communicating with the hole is formed, and the optical fiber communicating with each optical fiber insertion microhole between each optical fiber insertion microhole and the optical fiber insertion port of each microinsertion hole group In the ferrule for a multi-core multi-stage optical connector in which an insertion guide groove is formed, the center of the optical fiber insertion micro hole on the j-th optical fiber insertion guide groove side from the bottom is connected to the upper part of the entrance of the optical fiber insertion port. When the angle formed by the straight line and the axis of the optical fiber insertion microhole is the optical fiber insertion angle α (j), and the length of the optical fiber insertion guide groove at the j-th stage from the bottom is L (j),
L (j) ≧ k · α (j) ^−0.5 (k = 1) and
0.3mm ≦ L (j) ≦ 1.0mm
The multi-fiber multi-stage optical connector ferrule is characterized in that the optical fiber insertion angle α (j) and the length L (j) of the optical fiber insertion guide groove are formed to satisfy the relationship.

  In the present invention, the angle α (j) formed by each step and the length L (j) of the optical fiber insertion guide groove are configured so as to satisfy the above formula, so that the optical fiber insertion angle α can be reduced. Since the length L (j) of the optical fiber insertion guide groove is increased, the optical fiber can be easily pressed against the optical fiber insertion guide groove, and the optical fiber insertion property can be improved.

  In the following, the present invention will be described in more detail with reference to the illustrated embodiments. The embodiment shown in FIG. 1 is a ferrule for a four-stage multi-core multi-stage optical connector. The distance d between the optical fiber insertion microholes 12 in each stage is 0.25 mm, and the size of the gap D between the optical fiber insertion openings 17 is 1.80 mm. The length G between the lower optical fiber insertion micro-hole 12 on the optical fiber insertion guide groove 18 side and the entrance of the optical fiber insertion port is 4.10 mm, and the optical fiber on the optical fiber insertion guide groove side at the jth stage from the bottom. This is a case where the height difference D0 between the center position of the insertion micro hole 12 and the upper part of the entrance of the optical fiber insertion port 17 is set to 1.33 mm.

  When an optical fiber is inserted into the first-stage optical fiber insertion micro-hole 12, the optical fiber insertion angle α is 17.9 °, and L (1) = 1 / √17.9 = 0.236 mm from Equation 1 above. However, since the optical fiber insertion guide groove 18 is desirably 0.3 mm or more, the length L (1) of the optical fiber insertion guide groove is set to 0.30 mm. In the second stage, the optical fiber insertion angle α is 13.7 °, and L (2) = 1 / √13.7 = 0.270 mm. Therefore, L (2) = 0.3 mm as in the first stage. Since the optical fiber insertion angle α is 9.9 ° at the third stage, L (3) = 1 / √9.9 = 0.318 mm from Equation 1 above. Since it may be longer than this, the third place after the decimal point is moved up to L (3) = 0.32 mm. In the fourth stage, since the optical fiber insertion angle is 6.5 °, L (4) = 1 / √6.5 = 0.392 mm, and the length L (4) of the optical fiber insertion guide groove is set to 0.4 mm.

  With the ferrule for a multi-fiber multi-stage optical connector configured as described above, the optical fiber 20 can be easily inserted into the optical fiber insertion microhole 12 without causing the optical fiber to break.

  Further, the thus formed ferrule for a multi-core multi-stage optical connector is then incorporated into a frame housing as in the conventional case to constitute an optical connector.

  In the above-described embodiment of the present invention, the four-stage multi-core multi-stage optical connector ferrule has been described as an example. However, the present invention may be other multi-core multi-stage optical connector ferrules. The dimension is also an example, and any value may be used as long as it satisfies the above approximate expression.

Sectional drawing which shows one Example of this invention. The characteristic view which shows the experimental result prior to this invention. Explanatory drawing for demonstrating the dimension of an optical connector. Cross-sectional explanatory drawing which shows an example of the assembly process of optical kneaders. Sectional drawing which shows an example in the other assembly process of an optical connector. Sectional drawing which shows an example in the further another assembly process of an optical connector. Sectional drawing which shows an example in the further another assembly process of an optical connector. Sectional drawing which shows an example in the further another assembly process of an optical connector. Sectional drawing which shows the optical connector for a comparison. Sectional drawing of an example of the past. The perspective view of an example of the said conventional.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Ferrule 11 for multi-fiber multistage optical connectors One end 12 Optical fiber insertion fine hole 13 Fine insertion hole group 16 Other end 17 Optical fiber insertion port 18 Optical fiber insertion guide groove 19 Adhesive injection hole 20 Optical fiber

Claims (2)

A plurality of optical fiber insertion microholes arranged in a horizontal row at one end are formed in a plurality of stages, and one optical fiber communicating with each of the optical fiber insertion microholes at the other end An insertion port is formed, and an optical fiber insertion guide groove communicating with each optical fiber insertion microhole is formed between each optical fiber insertion microhole and the optical fiber insertion port of each of the microinsertion hole groups. In the ferrule for a multi-stage optical connector, a straight line connecting the center of the optical fiber insertion microhole on the j-th optical fiber insertion guide groove side from the bottom and the upper part of the entrance of the optical fiber insertion port, and the optical fiber insertion microhole When the angle formed with the axis is the optical fiber insertion angle α (j), and the length of the optical fiber insertion guide groove at the j-th stage from the bottom is L (j),
L (j) ≧ k · α (j) ^−0.5 (k = 1) and
0.3mm ≦ L (j) ≦ 1.0mm
The multi-fiber multi-stage optical connector ferrule is characterized in that the optical fiber insertion angle α (j) and the length L (j) of the optical fiber insertion guide groove are formed so as to satisfy the relationship. A multi-fiber optical connector comprising the ferrule for a multi-fiber optical connector according to claim 1.

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