JPH02281208A - Variable light branching/coupling device - Google Patents

Abstract

PURPOSE:To optionally vary the branching ratio of light by melting and splicing one part of the outside circumferential surfaces of two or more optical fibers each other, mechanically drawing the spliced part in the optical axis direction of the optical fiber and pressurizing and shaping around the center of the spliced part in a vertical direction to the optical axis. CONSTITUTION:After one part of the outside circumferential surfaces of the optical fibers 11 and 12 consisting of an elastic member are heated, melted and spliced each other, the drawn melted and spliced part is gradually thinned and drawn until the outside diameter of the central part of the melted and spliced part 13 becomes almost the thickness of one optical fiber. At this time, the thickness of the melted and spliced part 13 is controlled by varying the drawing length of the melted and spliced part 13 and simultaneously pressurizing it from the vertical direction to the optical axis. Thus, the quantity of the light coming through one optical fiber 11 at the melted and spliced part 13 can be varied. As the result, the branching ratio of the light is optionally varied.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an optical branching/coupling device for branching light into two or more parts, which is used for optical communication/optical measurement.

2. Description of the Related Art Conventionally, this type of optical branching coupler has had a configuration as shown in FIG. In FIG. 3, 1 and 2 are optical fibers,
Reference numeral 3 denotes a fused spliced portion formed by heating and melting a part of the outer peripheral surfaces of the optical fibers 1 and 2 to connect them and then stretching them.

The central part of the fusion splicing part 3 has an outer diameter gradually narrowed (stretched) to the thickness of one optical fiber, and the core part through which the light of the optical fibers 1 and 2 passes also becomes thin.

In the figure, light entering through the end face 4 of the optical fiber 1 becomes thinner at the fusion splice 3, so some of the light begins to wet the optical fiber 1 and is coupled to the optical fiber 2 (evanescent coupling). .

As a result, the light that has entered through the end face 4 of the optical fiber 1 is divided into the end face 5 of the optical fiber 1 and the end face 6 of the optical fiber 2 and then emitted.

As described above, an optical branching coupler has conventionally been configured.

Problems to be Solved by the Invention In such a conventional configuration, the branching ratio of light incident from the end face 4 of the optical fiber 1, that is, the end face 5 of the optical fiber 1,
The ratio of the light that is split into the end face 6 of the optical fiber 2 and emitted is determined based on the structural conditions such as the length and thickness of the fused splice 3.
This has the disadvantage that the light branching ratio cannot be arbitrarily varied because it is determined uniquely.

The present invention is intended to solve these problems, and aims to provide an optical branching coupler that can arbitrarily vary the light branching ratio by mechanical adjustment from the outside.

Means for Solving the Problems In order to solve the problems, the present invention fuses and connects parts of the outer peripheral surfaces of two or more optical fibers made of transparent elastic members to each other, and connects the fused joints to the optical fibers. The structural conditions of the fused joint, that is, the stretched length and thickness, are changed by mechanically stretching the fused joint in the direction of the optical axis and applying pressure in the direction perpendicular to the optical axis around the center of the fused joint. It is composed of

Function The present invention allows the stretching length and thickness of the fusion spliced portion to be arbitrarily changed by the above-described configuration, so the amount of light that permeates through one optical fiber of the fusion spliced portion can be varied.
As a result, it functions as an excellent optical branching coupler that can arbitrarily vary the branching ratio.

Embodiment FIG. 1 shows the configuration of a variable optical branching coupler according to an embodiment of the present invention. In the same figure, 11 and 12 are transparent elastic members 7 and optical fibers, and 13 is an optical fiber 11 and 1.
After heating and melting a part of the sides of the sag 11 of 2 and connecting them, the fused joint part 13 is stretched, and the central part of the fused joint part 13 gradually has an outer diameter approximately equal to the thickness of one optical fiber. Fine (
The core portions of the optical fibers 11 and 12 through which the light passes are also thin. 14 and 15 are holding portions fixed to both ends of the fusion splicing portion 13, respectively, and the adjusting screw 16 is rotated. This constitutes a stretching part that changes the interval between the holding parts 14 and 15. 17 and 18 are pressure parts that pressurize the vicinity of the center of the fused joint part 13 from both sides to shape the outer shape of the fused joint part 13; 19 is the holding part 14.1
5 and the operation of the pressurizing parts 17 and 18.

In the figure, the light incident from the end face 4 of the optical fiber 11 becomes thinner at the fusion splice 13, so that
Some of the light begins to get wet from the optical fiber 11, and the optical fiber 1
2 (evanescent bond). As a result, the light incident from the end face 4 of the optical fiber 11 is divided into the end face 5 of the optical fiber 11 and the end face 6 of the optical fiber 12 and output.

Here, since the optical fibers 11 and 12 are made of transparent elastic members, by rotating the adjusting screw 16 and varying the distance between the holding parts 14 and 15, the fusion splicing part 13 is moved in the optical axis direction. expand and contract. In addition, the pressurizing part 17.1
Since the fusion joint 13 is pressurized from both sides by 8,
The outer shape of the fusion joint 13 near the center is shaped to be even thinner.

The structure of the fused joint 13 determines the light splitting ratio. When the core spacing of optical fibers is narrowed, the interaction of light between the optical fibers becomes stronger. FIG. 2 shows the relationship between the extension length of the fused splice 13 and the amount of light emitted from each optical fiber in the optical branching coupler of FIG. 1. optical fiber 11
Assuming that the amount of light emitted from the end face 5 of the optical fiber 12 is the characteristic 20 in the figure, and the amount of light emitted from the end face 6 of the optical fiber 12 is the characteristic 21, even if most of the light is emitted from the fiber 11 at the beginning, the extension length will increase. At the same time, the branching ratio of the optical fibers 11 and 12 becomes 1:1, and then the branching ratio is reversed.

Returning to Figure 1 again, we will continue the explanation. When the adjustment screw 16 is rotated to vary the distance between the holding parts 14 and 15, the fusion joint part 13 expands and contracts in the optical axis direction, so that the extension length changes. Further, by applying pressure from the direction perpendicular to the optical axis of the pressurizing parts 17 and 18, the center of the extending part 13 becomes thinner, and the core distance between the optical fibers 11 and 12 becomes narrower.

As a result, it is possible to arbitrarily vary the ratio of the amount of light that enters from the end surface 4 of the optical fiber 11 and is split into the end surface 5 of the optical fiber 11 and the end surface 6 of the optical fiber 12 and output. Ru.

Here, the control unit 19 functions to control the stretching length and the degree of pressure of the fusion joint 13 to optimal values by interlocking the interval between the holding parts 14.15 and the pressing part 17.18. .

The feature of this configuration is that parts of the outer peripheral surfaces of optical fibers made of transparent elastic members are fused and connected to each other, and this fused spliced portion 13 is stretched in the optical axis direction of the optical fiber.
The thickness of the fused joint 13 was controlled by changing the length of the fused joint 13 and applying pressure in a direction perpendicular to the optical axis in conjunction with this operation.

The variable optical branching coupler shown in Fig. 1 can obtain any optical branching ratio by adjusting it from the outside. Therefore, in a communication system using an optical fiber as a signal transmission path, the optical fiber of this variable optical branching coupler can be used. By using one end as an input/output end for optical signals and coupling the other end to a light emitting or light receiving element of an optical transmitting section or an optical receiving section, an optical transceiver can be constructed that allows easy design and modification of a communication network.

In this embodiment, an optical two-branch coupler using two optical fibers has been described, but the number of optical fibers used may be any number depending on the number of branches.

Further, although an adjustment screw is used in this embodiment as a means for stretching the fusion spliced portion, no mention will be made of any means for mechanically stretching the fusion spliced portion in the optical axis direction.

Furthermore, as a means for shaping the shape of the fusion joint, two pressurizing parts were used in this example, but if there is a means for applying pressure in a direction perpendicular to the optical axis of the fusion joint, the number, direction, This does not limit the shape of the pressurizing part, etc. In addition, a control unit for interlockingly controlling the stretching and pressurizing operations of the molten joint (e.g., electrical control or mechanical control may be used).

Effects of the Invention As described above, according to the present invention, parts of the outer circumferential surfaces of optical fibers made of transparent elastic members are fused and connected to each other, and this fused spliced portion is formed to have an arbitrary length in the optical axis direction of the optical fiber. At the same time, the outer shape can be shaped by applying pressure near the center of the fused splice in a direction perpendicular to the optical axis, so as the structure of the fused splice changes, the light that leaks out from one optical fiber in the fused splice can be adjusted. As a result, an effect can be obtained in which the optical branching ratio can be arbitrarily varied.

Furthermore, as mentioned above, any optical branching ratio can be obtained by external adjustment, so in a communication system using an optical fiber as a signal transmission path, one end of the optical fiber of this variable optical splitter coupler can be used to transmit optical signals. By using one end as an input/output end and coupling the other end to a light emitting or light receiving element of an optical transmitting section or an optical receiving section, an optical transceiver can be constructed that allows easy design and modification of a communication network.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a variable optical branching coupler according to an embodiment of the present invention, FIG. 2 is an explanatory diagram of a change in branching ratio of the variable optical branching coupler,
FIG. 3 is an explanatory diagram of the configuration of a conventional optical branching coupler. 4.5.6...End face of optical fiber, 11.12
......Optical fiber 13...Fused connection part, 14.15...Holding part, 16...Adjustment screw, 17.18 Pressure part, 19. ...control section. Name of agent: Patent attorney Shigetaka Awano and 1 other person Matometo 42-Tang゛ζnabe, Koh =--Hibori Shichiyotu 5 times

Claims (3)

[Claims] (1) two or more optical fibers made of transparent elastic members whose outer peripheral surfaces are partially fused and connected to each other, and a stretching section that mechanically stretches the fused spliced portion in the optical axis direction of the optical fiber; , comprising a shape shaping section that applies pressure in a direction substantially perpendicular to the optical axis to shape the vicinity of the center of the fusion spliced section, which enters from one end of an arbitrary one of the optical fibers, A variable optical branching coupler characterized by varying the branching ratio of light emitted from the other end of a fiber. (2) Claim (2) further comprising a control unit that interlocks the operation of the stretching unit and the operation of the shape shaping unit.
1) The variable optical branching coupler described above. (3) Claim characterized in that one end of the variable branching coupler is used as a light input/output end, and the other end is coupled to a light emitting/receiving element.
1) The optical transceiver described above.