Multicore optical connector

Abstract: A multicore optical connector includes a connector body (20) having a pair of alignment pin holes (21) and a plurality of optical fiber holes (22) formed therebetween and optical fibers inserted in the optical fiber holes (22) such that the end faces of the optical fibers are exposed through the optical fiber holes (23). In the multicore optical connector, the optical fiber holes (22) are divided into optical fiber hole groups (23) of a number which coincides with the number of the groups of the optical fibers, and the optical fiber hole groups (23) are separated from one another.

Description: The present invention relates to a multicore optical connector for use in connecting multicore optical fiber. A conventional multicore optical connector has a structure such as is shown in Fig. 1. Referring to Fig. 1, numerals 10 and 11 denote multicore optical connectors. End faces 10a and 11a of the multicore optical connectors 10 and 11 have a pair of alignment pin holes 13 and optical fiber holes 12 formed therebetween. Optical fibers of a multicore optical fiber tape 16 are inserted in the optical fiber holes 12 so that the end faces thereof are exposed. A pair of alignment pins 14 are inserted in the alignment pin holes 13 of the multicore optical connectors 10 and 11. More specifically, one end portion of the pair of alignment pins is inserted in the alignment pin holes 13 of the connector 10, and the other end portion is inserted in the alignment pin holes 13 of the connector 11. In this manner, the connection end faces 10a and 11a of the connectors 10 and 11 are brought into contact with each other. Thereafter, the connectors 10 and 11 are held together by an elastic clip 15. As described above, the conventional multicore optical connector has a plurality of optical fiber holes arranged in a row and interposed between a pair of alignment pin holes 13. With this structure, only two to nineteen optical fibers can be connected at a time by using conventional multicore optical connectors. In recent years, with the expansion of optical communication networks to transmit a greater amount of information, demand has arisen for a more compact optical connector for connecting a greater number of optical fibers than is possible using conventional optical connectors. If the pitch of the optical fiber holes is reduced to increase the number of optical fiber holes, it becomes difficult to determine which optical fiber should be inserted in which optical fiber hole. As a result, the efficiency with which multicore optical connectors are manufactured is greatly reduced. Further, the number of optical fibers contained in one multicore optical fiber tape cannot be changed. Therefore, to manufacture a multicore optical connector for connecting a greater number of optical fibers, it is necessary to use a plurality of multicore optical fiber tapes. Thus, if the optical fiber holes are arranged at regular pitches, the side end portions of adjacent optical fiber tapes will overlap each other when optical fibers are inserted in the optical fiber holes. As a result, optical fibers near the end portion of an optical fiber tape may be bent. This bent or the like is undesirable since it may cause the increase of connection loss. JP-A-60135911 describes an optical cable connector for use with a vertical array of flat optical multi-core cables. A mould is used to set the cables into resin. After removal from the mould the front surface of the connector is cut and polished to expose the cut faces of each fibre. Dummy connecting pins are located in the mould which are subsequently removed from the moulded part and replaced with final ones which are secured by adhesive. JP-A-59-49510 describes a multi-core connector for optical cable. The connector consists of a block attached to the ferrule base plate, said block having through-holes for the individual fibres. In the surface of the ferrule there is a tapered guide hole for the flat optical cable. Abutting the block grooves are provided in the surface of the ferrule base for location of the individual fibres. The fibres and the flat optical cable are set into the grooves with adhesive. An object of the present invention is to provide a compact multicore optical connector which can connect a greater number of optical fibers than a conventional optical connector, while reducing the possibility of connector loss. The object of the invention can be attained by a multicable optical fiber connector comprising a connector body having a pair of holes for receiving alignment pins, a passageway through the body an end of which comprises a plurality of optical fiber holes formed between the alignment pin holes, a plurality of optical fiber cables inserted into the passageway with their constituent optical fibers passing through the fiber holes such that the end faces of the optical fibers are exposed at the outer ends of the optical fiber holes, wherein the optical fiber holes are divided into a number of fiber hole groups which coincides with the number of optical cables, said optical fiber hole groups being distanced from one another, characterized in that said optical fiber hole groups are arranged in and extending along a plane parallel to a line joining said alignment pin holes, in that an opening is formed in a major surface of the connector body which communicates with the passageway, and in that the bottom of the passageway comprises a plurality of partitioning portions projecting from and arranged along said passageway, for guiding and separating the groups of fibers belonging to each cable. This invention can be more fully understood from the following detailed description when taken in conjunction with the accompanying drawings, in which: Fig. 1 is a perspective view showing a conventional multicore optical connector; Fig. 2 is a diagram showing a multicore optical connector according to an embodiment of the present invention; Fig. 3 is a plan view of the multicore optical connector shown in Fig. 2; Fig. 4 is a cross-sectional view of the multicore optical connector taken along the line A-A in Fig. 3; and Fig. 5 is a diagram showing a multicore optical connector according to another embodiment of the present invention. Embodiments of the multicore optical connector of the present invention will now be described, with reference to the accompanying drawings. Figs. 2 to 4 show an embodiment of the present invention. The connection end face of the multicore optical connector 20 has a pair of alignment pin holes 21. Optical fiber holes 22 are formed between the alignment pin holes 21. The optical fiber holes 22 are divided into a plurality of optical fiber hole groups 23, each constituted by a plurality of optical fiber holes arranged at a pitch of about 180 to 250 µm. It is desirable that the distance D between the optical fiber hole groups should be 300 to 1500 µm. If the distance D is smaller than 300 µm, distance D is indistinguishable from the pitch of optical fiber hole, and if it is greater than 1500 µm, the size of the optical connector is to be large. Although the number of the optical fiber holes 22 constituting one optical fiber hole group 23 is set to 16 in the embodiment shown in Fig. 2, it can be changed in accordance with the number of optical fibers contained in an optical fiber tape. It is desirable that the number of the optical fiber holes 22 should coincide with the number of the optical fibers included in the optical fiber tape. Although the number of the optical fiber hole groups 23 is three in the embodiment shown in Fig. 2, it may be two or more than three so that number of the optical fiber hole groups matchs the number of the optical fiber tape. As shown in Figs. 3 and 4, an opening 25 is formed in the central portion of a main surface 24 of the multicore optical connector 20 so as to reach to the optical fiber holes 22. Guide portions 26, on which optical fiber tapes are placed, are formed at the bottom of the opening 25 and partitioned by partitioning portions 27. The number of the guide portions 26 coincides with the number of the optical fiber hole groups 23 (e.g., three, in this embodiment). Optical fiber tape inserting holes 28 are formed in the end face on the opposite side of the multicore optical connector from the connection end face. The optical fiber tape inserting holes 28 communicate with the opening 25. The partitioning portions 27 reaches the end face of the optical connector 20 having the optical fiber tape inserting holes 28. Thus, the mechanical strength of the optical connector 20 is improved, thereby preventing the optical connector from cracking. The cross section of the partitioning portions 27 may be semicircular as shown in Fig. 4, or rectangular. When optical fibers are to be loaded in the above-described multicore optical connector, for example, three 16-core optical fiber tapes and boots are inserted through the optical fiber tape inserting holes 28. The optical fiber tapes are guided by the guide portions 26 and the optical fibers are inserted in the corresponding optical fiber holes 22. At this time, the optical fiber tapes do not overlap or interrupt each other by virtue of the partitioning portions 27. Since the opening 25 is formed in the multicore optical connector, the optical fiber tapes can be inserted very easily. Further, since the optical fiber holes 22 are divided into three optical fiber hole groups 23, the optical fibers can be inserted to the corresponding optical fiber holes without failure. Moreover, since the optical fiber hole groups 23 are separated at the distance D from one another, the optical fiber tapes do not overlap when inserted. As a result, the optical fibers are prevented from being bent, thereby reducing the connection loss. Fig. 5 shows another embodiment of the multicore optical connector according to the present invention. A multicore optical connector 20 has a pair of alignment pin holes 21 and six optical fiber hole groups 23 arranged in two rows and three columns between the alignment pin holes 21, each group consisting of 8 optical fiber holes 22. With this arrangement, a more highly integrated multicore optical connector can be obtained. As has been described above, the multicore optical connector of the present invention is more compact and capable of connecting a greater number of optical fibers with less connection loss as compared to a conventional connector. Thus, it is well suited for application to an optical communication network for transmitting a large amount of information.

Claims: A.multicable optical fiber connector comprising a) a connector body (20) having a pair of holes (21) for receiving alignment pins, b) a passageway through the body an end of which comprises a plurality of optical fiber holes (22) formed between the alignment pin holes (21), and c) a plurality of optical fiber cables inserted into the passageway with their constituent optical fibers passing through the fiber holes (22) such that the end faces of the optical fibers are exposed at the outer ends of the optical fiber holes (22), d) the optical fiber holes (22) being divided into a number of fiber hole groups (23) which coincides with the number of optical cables, and e) said optical fiber hole groups (23) being distanced from one another, characterized by f) said optical fiber hole groups (23) being arranged in and extending along a plane parallel to a line joining said alignment pin holes (21), g) an opening (25) formed in a major surface (24) of the connector body (20) which communicates with the passageway, and h) the bottom of the passageway comprising a plurality of partitioning portions (27) projecting from and arranged along said passageway, for guiding and separating the groups of fibers belonging to each cable. A multicable optical fiber connector according to claim 1, characterized in that each of the optical fiber hole groups (23) is constituted by two to nineteen optical fiber holes (22). A multicable optical fiber connector according to claim 1, characterized in that the plurality of optical fiber hole groups (23) are constituted by a plurality of columns.

Inventors: HAIBARA TADASHI, MATSUMOTO MICHITO, OOTA TOSHIHIKO, SAITO MASAMI, YAMADA HIROYUKI, YAMAKAWA JUN, HAIBARA, TADASHI, MATSUMOTO, MICHITO, OOTA, TOSHIHIKO, SAITO, MASAMI, YAMADA, HIROYUKI, YAMAKAWA, JUN, Oota, Toshihiko, c/o THE FURUKAWA ELECTRIC CO.,LTD, Saito, Masami, c/o THE FURUKAWA ELECTRIC CO., LTD., Yamada, Hiroyuki, c/o THE FURUKAWA ELECTRIC CO.LTD, YAMAKAWA, JUN, C/O THE FURUKAWA ELECTRIC CO., LTD.
Applicants: FURUKAWA ELECTRIC CO LTD, NIPPON TELEGRAPH & TELEPHONE, NIPPON TELEGRAPH AND TELEPHONE CORPORATION, THE FURUKAWA ELECTRIC CO., LTD.
Application year: 1992
Main classification: G02B6
IPC codes: G02B6