OPTICAL FIBER CONNECTION

Abstract: An optical fiber connection comprising at least one optical fiber (2) to which a pair of coated optical fibers (1) is connected and at least one additional optical fiber (1) which can cope with urgent repair of a broken optical fiber in the connection.

Description: The present invention relates to an optical fiber connector, and to the use of the connector. EP-A-0 109 648 discloses an optical connector comprising: two connector bodies joined together at corresponding matching faces, each connector body comprising a plurality of holes extending between its matching face and an opposite face, each hole supporting an end portion of an optical fibre, said end portion extending to and being unsheathed in the proximity of the matching face where it is connected to the end portion of another optical fibre supported in a corresponding position in the respective other connector body. A typical conventional single core assembled type optical connector is shown in Figs. 1A and 1B of the accompanying drawings, which are respectively a longitudinal section and a side elevation of the connector. In these Figs. numeral 1 represents a sheathed (coated) optical fiber, numeral 2 represents an unsheathed optical fiber portion, numeral 3 represents a ferule in which the optical fiber portion 2 is positioned and fixed, and numeral 4 represents a guide hole receiving pin for positioning the connected ferule 2. As shown in the Figs., the number of the optical fibers to be connected and that of the sheathed optical fibers installed in the connector are the same. Therefore, once one of the fibers in the connector should be damaged or broken in the assembling field, the connector has to be re-brazed in place, or the whole connector has to be replaced, or all the fibers have to be reconnected by means of sheathed optical connector fibers. Fig. 2 is a longitudinal section of a generally fusion-spliced connection of three single core sheathed optical fibers 1 reinforced by a heat-shrinkable tube 5. In this Fig., numeral 2 represents a fusion spliced optical fiber, numeral 6 represents a reinforcement steel wire, and numeral 7 represents a hot melt adhesive filling the gap between the fibers. With such fusionspliced connection, if one fiber is broken, all three fibers should be reconnected. One object of the present invention is to provide an optical fiber connection which can overcome at least some drawbacks associated with the conventional optical fiber connections. Another object of the present invention is to provide an optical fiber connection which can cope with urgent repair of a broken optical fiber in the connection. According to one aspect of the invention, there is provided an optical connector comprising: two connector bodies joined together at corresponding matching faces, each connector body comprising a plurality of holes extending between its matching face and an opposite face, each hole supporting an end portion of an optical fibre, said end portion extending to and being unsheathed in the proximity of the matching face where it is connected to the end portion of another optical fibre supported in a corresponding position in the respective other connector body, the connector body being characterized in that each connector body comprises at least one additional hole extending between said matching and opposite faces, each additional hole supporting one end portion of a piece of optical fibre, the other end portion of which protrudes from said opposite face and is of a relatively short length compared with the other fibres, the pieces supported in corresponding positions in the two connector bodies being connected together, the resulting connection being arranged to be substituted for the connection between two other fibres when the latter connection breaks. According to another aspect of the invention, there is provided an optical connector comprising a first and a second plurality of optical fibres, each fibre of one plurality having an unsheathed end portion which is coaxially aligned with and connected to an unsheathed end portion of a fibre of the other plurality, the connected end portions being embedded in a hot-melt adhesive enclosed in a heat-shrink tube, characterized in that said hot-melt adhesive also supports at least one piece of sheathed optical fibre whose opposite end portions protrude from the adhesive and are of a relatively short length compared with the fibres of said first and second plurality. For a better understanding of the invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:- Figs. 1A & 1B are a longitudinal section and a side elevation respectively of a conventional single core assembled type optical connector; Fig. 2 is a longitudinal section of a generally fusion-spliced connection of three pairs of single core sheathed optical fibers which connection is reinforced by a heat-shrinkable tube; Figs. 3A & 3B are a longitudinal section and a side elevation respectively of one embodiment of the optical fiber connection according to the present invention; Fig. 4 is a longitudinal section of a generally fusion-spliced connection of three pairs of single core sheathed optical fibers according to a further embodiment of the present invention, which connection is reinforced by a heat-shrinkable tube; and Figures 5A and 5B show repaired connections. Figures 3A and 3B show one embodiment of optical fiber connection according to the present invention, in which the same numerals represent the same elements as in Figures 1A and 1B. In this type of the connection, although the connector is to be used for connecting three optical fibers 1, it includes an additional sheathed optical fiber 11, which is cut at a predetermined length from the connector, for example, one meter. The connector is supplied in a form including such additional optical fiber 11 and used in place. Three optical fibers 1 of the connector are connected to three sheathed optical fibers while the additional optical fiber 11 is left unconnected. As shown in Figure 5A, if one pair 1a of the connected optical fibers gives trouble, each side of the fiber 1a is cut at the positions A and reconnected to the additional optical fiber 11 at the positions B. Figure 4 shows a generally fusion-spliced connection of three single core optical fibers 1 which connection is reinforced by a heat-shrinkable tube 5. This connection also includes an additional optical fiber 11, which is reinforced by the tube 5 in the same manner as the other optical fibers being reinforced. If one pair 1a of the connected optical fibers gives trouble, the fiber 1a is cut at the positions A and reconnected to the additional optical fiber 11 at the positions B as shown in Figure 5B. In the above description, one additional optical fiber is used, although two or more additional optical fibers may be included in the connection within the scope of the present invention. When five optical fibers are connected by means of an optical connector similar to that shown in Figure 1, and one of them is broken, it takes 2 or 3 hours to reconnect all five fibers with a new connector, or it takes at least one hour to replace the troubled connector with a Pigral type connector, since the fibers should be fusion-spliced. In contrast, when the connector including the additional optical fiber according to the present invention is used, only the broken fiber is to be reconnected to both ends of the additional fiber. This takes less than 30 minutes, which is one fourth to one sixth of that required in case of the conventional optical connector, and a half of that required with use of the Pigral type connector. While the repair of the fusion-spliced connection of five optical fibers takes about one hour by the conventional method, it takes less than 30 minutes according to the present invention.

Claims: An optical connector comprising: two connector bodies (3) joined together at corresponding matching faces, each connector body comprising a plurality of holes extending between its matching face and an opposite face, each hole supporting an end portion (2) of an optical fibre (1), said end portion (2) extending to and being unsheathed in the proximity of the matching face where it is connected to the end portion of another optical fibre supported in a corresponding position in the respective other connector body, the connector body being characterized in that each connector body (3) comprises at least one additional hole extending between said matching and opposite faces, each additional hole supporting one end portion of a piece of optical fibre (11), the other end portion of which protrudes from said opposite face and is of a relatively short length compared with the other fibres, the pieces supported in corresponding positions in the two connector bodies being connected together, the resulting connection being arranged to be substituted for the connection between two other fibres when the latter connection breaks. An optical connector comprising a first and a second plurality of optical fibres (1), each fibre of one plurality having an unsheathed end portion (2) which is coaxially aligned with and connected to an unsheathed end portion (2) of a fibre of the other plurality, the connected end portions being embedded in a hot-melt adhesive enclosed in a heat-shrink tube, characterized in that said hot-melt adhesive (7) also supports at least one piece of sheathed optical fibre (11) whose opposite end portions protrude from the adhesive (7) and are of a relatively short length compared with the fibres (1) of said first and second plurality. A connector according to claim 1, wherein each said piece of optical fiber (11) has an unsheathed portion within the associated body (3). A connector according to claim 2 comprising at least two said pieces of optical fibre (11). A connector as claimed in claim 1 or 3 wherein each body comprises at least two said pieces of optical fiber (11). A connector according to claim 1,3 or 5, wherein said body contains hot-melt adhesive in which said fibers are embedded. The use of a connector according to any of claims 1 to 6 to enable the optical path provided by a malfunctioning fiber within said body to be replaced by an optical path provided by the spare fiber without replacing the entire connector.

Inventors: KAKII, TOSHIAKI C/O YOKOHAMA WORKS, MATSUNO, KOICHIRO C/O YOKOHAMA WORKS
Applicants: SUMITOMO ELECTRIC INDUSTRIES LIMITED
Application year: 1985
Main classification: G02B6
IPC codes: G02B6