JPS62153906A - Optical branching and coupling device - Google Patents

Abstract

PURPOSE:To easily constitute an optical branching and coupling device with small loss by bundling plural optical fiber cables formed by adhering clads of plastic to outer peripheries of cores after removing clads at their intermediate parts, and welding them in one body. CONSTITUTION:A clad 4b is removed at the coupling part 5 of a branch path optical fiber cable 4 and remaining cores 4a are bundled in one, drawn while heated, and welded into one core 4a'. In this case, the sectional area of the core 4a is made smaller that the total sectional area of respective branch path optical fiber cables 4. Each branch path optical fiber cable 4 has its clad 4b removed nearby its coupling part 5, no light leaks to the clad, and light guided out to the fiber cable 4 is prevented from having loss. Further, there is no join part between the branch path optical fiber cable 4 and coupling part 5, so the loss further decreases. When the coupling part 5 is formed, the clad 4b of the branch optical fiber cable 4 is removed and cables are only welded in one, thereby easily forming the device.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an optical branching/coupling device that branches or couples light in a communication transmission path of, for example, optical fiber communication.

[Technical background of the invention and its problems] In recent years, in the field of communication technology, the use of communication has become more frequent and large capacity communication transmission paths are required, and ultra-high-speed data, video, etc. As the demand for new communications increases, optical fiber communications that can easily realize these requirements are being developed.

By the way, when this optical fiber communication is used as a communication transmission line in a network system such as a LAN, it is necessary to branch this communication transmission line into multiple ports and connect them.

Generally, the branching and coupling of communication transmission lines in optical fiber communication is as shown in FIG.
・Two are combined and performed.

As shown in FIG. 6, the branch optical fiber cable 2 is
A cladding 2b made of quartz is similarly applied to the outer periphery of the core 2a made of quartz. Each end of these branch optical fiber cables 2 is bundled into a bundle, and this part is heated, stretched, and fused to form a large number of cores inside one cladding 2b', as shown in FIG. 2a is formed as a light branching/coupling section 3.3.

Then, the optical branching/coupling portions 3 of these branch optical fiber cables 2 are joined to both ends of the mixing rod 1 to perform branching and coupling.

However, there are problems in that there are two joints between the optical branching/coupling section 3 of the branch optical fiber cable 2 and the mixing rod 1, which increases the loss factor and takes time and effort for the joints.

Furthermore, on the branching side of the optical branching/coupling section 3, the light emitted from the mixing rod 1 not only enters each core 2a of the optical branching/coupling section 3, but also enters the cladding 2b'. The loss will be large.

[Object of the Invention] The present invention has been made in response to such circumstances, and an object of the present invention is to provide an optical branching/coupling device that can be easily manufactured with low loss.

[Summary of the Invention] That is, the optical branching/coupling device of the present invention converges a plurality of optical fiber cables each having a plastic cladding on the outer periphery of the core by removing the cladding in the intermediate portion of each optical fiber cable, and integrates them into one. By being fused to the material, it can be manufactured easily with low loss.

[Embodiments of the Invention] Hereinafter, details of embodiments of the present invention will be described based on the drawings.

FIG. 1 is a schematic diagram showing an optical branching/coupling device according to an embodiment of the present invention.

As shown in the figure, branch optical fiber cables 4, 4, . reference).

At the joints 5 of these branch optical fiber cables 4, the cladding 4b is immersed in sulfuric acid, washed with water, and removed, and the remaining cladding 4a is collected into a bundle, stretched with heating, and fused. One core 4a'
(See Figure 3).

When forming the core 48' by fusion bonding as described above, the cross-sectional area of the core 4a' that enters the joint portion 5 is made smaller than the sum of the cross-sectional areas of the respective branch optical fiber cables 4. .

Therefore, as shown in the cross-sectional view in FIG. 4, the cladding 4b of each branch optical fiber cable 4 is removed near the coupling portion 5, so that no light escapes to the cladding, and the light emitted to the fiber cable 4 is , the occurrence of loss is prevented.

Furthermore, since this optical branching/coupling device does not have a joint between the branch optical fiber cable 4 and the coupling section 5, the loss is significantly reduced.

Further, when forming the coupling portion 5, the cladding 4b of the branch optical fiber cable 4 is removed and the cladding 4b is simply fused into a single bundle, making it easy to manufacture and improving mass productivity.

[Effects of the Invention] As explained above, according to the optical branching/coupling device of the present invention, the plastic cladding in the intermediate portions of each is removed, focused, and fused together, resulting in low loss and It can be easily manufactured.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an optical branching/coupling device according to an embodiment of the present invention, FIG. 2 is a longitudinal cross-sectional side view of a branch optical fiber cable of this optical branching/coupling device, and FIG. 3 is a schematic diagram showing this optical branching/coupling device.・A vertical side view of the coupling part of the coupling device, FIG. 4 is a schematic longitudinal sectional front view of this optical branching/coupling device, FIG. 5 is a schematic diagram showing a conventional optical branching/coupling device, and FIG. FIG. 7 is a longitudinal sectional side view of the branch optical fiber cable of the optical branching/coupling device. FIG. 7 is a longitudinal sectional side view of the optical branching/coupling section of the optical branching/coupling device.

Claims (1)

[Claims] An optical branching/coupling device characterized in that a plurality of optical fiber cables each having a plastic cladding on the outer periphery of the core are bundled by removing the cladding in the middle of each, and fused together. .