JPS6023324B2 - End face of optical fiber support for optical coupler and method for forming the end face - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coupling device for optical fibers, optical fiber cables, etc., and more particularly to an improved optical fiber support for use in a coupling device.

Optical transmission abbreviations used in optical communication systems, optical circuit testing, measurement, etc. each have different refractive indexes and are determined to a predetermined refractive index, and the optical glass or plastic that serves as the core and cladding layer is made of a predetermined refractive index. A thin wire with a cross-sectional dimension (hereinafter referred to as an optical fiber) is formed with a protective coating layer made of synthetic resin such as polyethylene ethylene or urethane on the outside, and an intermediate layer made of fibers such as polyimide resin (trade name: nylon) as a reinforcing material. Furthermore, there are optical fiber cables having an outer layer integrally extruded from materials such as polyethylene or vinyl, and optical fiber cords having a pongee diameter in which the optical fibers are coated with resin.

When such an optical fiber such as an optical fiber cable or cord is optically coupled to a main part of a device or other optical fiber, the end of the optical fiber is connected to an optical coupling bag.

When connecting the above-mentioned optical fibers to an optical coupling plate, since the optical fibers have a small diameter, they must be positioned correctly and connected so that there is no misalignment between the optical fibers (the axis relative to the central longitudinal direction of the optical fibers). At the same time, it is necessary to reduce reflection at the end face so that the transmitted light can be efficiently transmitted.

The structure of the optical coupling device is, for example, as shown in FIG. 1, a jack body 11 constituting a jack 1 and a plug 2 as an optical coupling device, and a plug body 21 having a cap nut 22 and a stopper 23 attached to the outside. Each fiber optic cable 6
, 6' are inserted, and optical fiber supports (cores) 3, 3' fixed with adhesive or the like are inserted.
There is one in which clampers 4 and 4' to which rubber bushings 5 and 5' are respectively attached are screwed to each other and fixed by tightening from the back surface of the large diameter outer peripheral portions 32 and 32' of the supports 3 and 3'. The reference outer peripheral part 31 of one optical fiber support 3 of this optical coupling device is iron-coupled with the inside of the reference hole 12 of the jack main body 11, and its position is determined by a stepped part 33. The protrusion of ' competes with the reference hole 12 of the jack main body 11 so that the end surfaces 34 and 34' abut each other,
The centrally located optical fiber ends of each are coupled.

In the conventional structure of the end surfaces 34 and 34', both of them are made into a plane perpendicular to the optical axis, and the ends of the optical fibers are also formed into optically smooth surfaces on the same plane so that light transmission can be carried out efficiently. ing.

Therefore, if the end faces of a pair of optical coupling devices come into contact with each other when joining, the most important optical fiber end will be scratched due to the pressing force that accompanies rotation, and optical distortion will repeatedly occur due to internal stress. There is also a risk of mechanical damage caused by attachment and detachment. In addition, since the transmitted light emitted from one optical fiber end is reflected multiple times between the end faces when entering from the other optical fiber end, a delayed minute signal is superimposed on the transmitted optical signal. Therefore, in order to eliminate the above-mentioned inconvenience, it is considered that the periphery including the end face of the optical fiber is appropriately set back to form a gap between the ends of the optical fiber. It has been proposed that a concave portion be formed by polishing a part of the spherical surface.

However, this polishing method requires a polishing disk with a specially shaped polishing surface, and since the polishing surface of the polishing disk only acts as a polishing surface in a limited area, it is difficult to obtain a good polished surface. There was a problem. In view of the above-mentioned problems, an object of the present invention is to provide a new shape and a method for forming the shape for providing a gap in the optical connection fiber portion facing the end face of the optical fiber support of an optical coupling device. In the case of an optical fiber support for an optical coupling device into which an optical fiber can be inserted, a concave groove formed of a part of a cylinder is formed on the end face of the support in a direction orthogonal to the optical ball with the optical fiber at the center. The outer diameter is D, the width of the groove is B, and B<D/ノ2.
The groove is formed by polishing the end surface of the support and the rotating surface of the cylindrical rotary polishing plate in parallel to the end surface of the support and perpendicular to the optical axis. ing.

With this concave arrangement, an appropriate gap is provided between the opposing abutting portions of the optical fibers, and polishing is not performed in concentrated areas with respect to the polishing disk, so that the end face of the optical fiber is optically preferable. It has the characteristic that it can be obtained.
Embodiments of the present invention will be described below based on the drawings. FIG. 2 shows a side view a and a front view b of an optical fiber support for an optical coupling device according to the present invention, and shows the concave grooves on the end face thereof.

In the optical fiber support 30, an optical fiber 61, which is a core wire of an optical fiber cable 6 inserted and fixed into the center from one end, is inserted and led out to the other end surface 34, and the optical fiber 61 is inserted and guided to the other end surface 34.
A concave groove 7, which is a part of the outer periphery of a cylinder (or birch or cylindrical outer surface), is formed in a direction perpendicular to the optical axis of the optical fiber with the center at the center. This concave groove 7 is formed of a groove having a radius R and a width B, centered around the optical fiber 61, and including the outer ridge D of the support body 30. For a pair of optical fiber cables and supports in the optical coupling device having the above structure, the coupling state is changed to 3 and 3' in Fig. 1, and the concave grooves on the opposing end faces are parallel to each other as shown in Fig. 3. When the optical fibers 61 and 61 are loosened, the end faces other than the concave groove 7 portion are abutted, and a gap is created between the opposing end faces of the optical fibers 61 and 61 due to the depth of the concave groove.

This gap prevents the pressing force from acting on the end of the optical fiber during coupling, and since the end face of the optical fiber does not come into contact with any part, this part will not be damaged by rubbing. In addition, the transmitted light emitted from the end of one optical fiber enters the other optical fiber from its end face through a gap, but at this time, most of the emitted light is determined by the closure number (N According to A), the light is emitted at a predetermined oblique angle with respect to the optical axis. Therefore, most of the incident light that is not directly incident and due to multiple reflections with the end face of the optical fiber is scattered to the outside, and the amount of reflected light that enters is extremely small. Although the relationship between the groove and the end face of the optical fiber is defined by the radius R, the core diameter portion of the optical fiber 61 that is to become an optical transmission line is extremely rough, and compared to this, the optical fiber support The outer diameter of the body 30 is extremely large, so R is also large compared to the core diameter. For this reason, the depth of the groove is usually very shallow, and the gap between opposing sides is also a small gap, which reduces loss in optical transmission. From the above, it is easy to understand that the concave surface due to the radius of the end surface of the core part is very small and almost a flat surface, and it has been confirmed that the concave surface effect optically has no practical effect. ing. This is particularly important when the opposing lenses are rotated relative to each other on the optical axis. The relationship between the outer dimension D of the optical fiber support 30 and the width B of the concave groove 7 is such that B<D in order to prevent the concave portions of the end faces 34 from falling into the concave grooves of the other at a 90° rotation position. / No Pig relationship should be used.

In this way, the two flat surfaces come into contact with each other, and the distance between the opposing optical fibers is maintained stably and constant. The present invention provides guidance (for example, a key,
Alternatively, it may be specified by providing a pin, etc., and normally it can be implemented without such consideration.

For example, as shown in FIG. 4, one optical fiber support 30 has a concave groove according to the present invention on the plug side, and the other optical fiber support 30 has a conventional end face on the jack side. It is possible to implement the optical fiber support 3 in any combination. Regarding the method for forming grooves on the end face of an optical fiber support of the present invention as described above, as shown in FIG. The end face 34 of the optical fiber support 30 is polished by the polishing plate 8.
Pressing from a direction parallel to the surface and perpendicular to the optical axis (arrow A),
A concave groove 7 as described above is formed by polishing around the end face of the optical fiber.

At this time, the polishing disk 8 and the optical fiber support 30 are supported by determining the positional relationship by a support device (not shown), and are then separated. Since the polishing disc 8 has a cylindrical shape, the relative relationship with the optical fiber support 30 is moved in a direction parallel to the surface as shown by arrows B and B', and polishing is performed at a specific position on the surface of the polishing disc 8. By avoiding this, the optical finish of the optical fiber end face can be made suitable. The above polishing plate 8
By using a groove whose diameter is twice the radius R of the groove, the groove can be formed into a desired shape.

Further, the polishing disk 8 itself may be a grindstone, or may be a device that performs polishing while applying an abrasive material of an appropriate particle size, and can be selectively implemented as appropriate. The optical coupling device and optical fiber support of the present invention are not limited to the above-mentioned embodiments, but may be applied in various modified or applied forms. This refers to a part of the cylindrical outer circumference.

As described above, the end face of an optical fiber support for an optical coupling device and the method for forming the end face according to the present invention include a part of the cylindrical outer periphery centered on the optical fiber in a direction orthogonal to the optical axis on the end face of the optical fiber support. By forming the concave groove, the optical fiber at the supporting end face is protected, and unnecessary reflected light from the feeding face is also removed from entering the transmission path. Furthermore, since the polishing disk is cylindrical, it exhibits excellent effects such as being able to polish the end face of the optical fiber to an optically favorable state.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view of an example of a jack and a plug, Fig. 2 is a side view a and a front view b of an optical fiber support for an optical coupling device according to the present invention, and Fig. 3 is a support together with an optical fiber cable. Combined state diagram showing only bodies for a pair, 4th
The figure is a diagram of another combined state, and FIG. 5 is a schematic explanatory diagram of a method of forming a groove on the end face of an optical fiber support. In the figure, 1 is a jack, 2 is a plug, 3 and 3' are optical fiber supports, 6 and 6' are optical fiber cables, 61,
61' is an optical fiber, 30 is an optical fiber support, 7 is a groove, and 8 is a polishing plate. *'Figure 2 Figure 3 Figure 4 Younger brother S figure

Claims (1)

[Scope of Claims] 1. In an optical fiber support for an optical coupling device into which an optical fiber can be inserted, a portion of a cylindrical outer periphery with the optical fiber as the center in a direction perpendicular to the optical axis is provided on the end face of the support. An end face of an optical fiber support for an optical coupling device, characterized in that the groove is formed such that the outer diameter of the support is D, the width of the groove is B, and B<D/√(2). 2. A concave groove formed by a part of a cylindrical outer circumference centered on the optical fiber in a direction orthogonal to the optical axis on the end face of the support of an optical fiber support for an optical coupling device into which an optical fiber can be inserted;
An optical fiber support for an optical coupling device, characterized in that a concave groove is polished by pressing the support end face and the rotating outer peripheral surface of a cylindrical rotary polishing plate parallel to the support end face and in a direction perpendicular to the optical axis. How to form the end of the body.