JPH03200902A - Optical fiber array - Google Patents

Abstract

PURPOSE:To eliminate the need for a grooved substrate and to inexpensively and efficiently produce the above optical fiber array by connecting and fixing the ends of plural pieces of optical fibers, from which protective coating layers are removed, by bringing the side faces into tight contact with each other or directly applying an unshaped adhesive material thereon. CONSTITUTION:Plural pieces of the glass optical fibers (bare fibers) 11 formed by removing the protective coating layers 20A of coated fibers 20 at the ends to expose the fibers are arranged in one array by bringing the side faces into tight contact with each other. These optical fibers 11... are connected and fixed at the points apart a slight distance from the end faces by the monolithic adhesive material 12 consisting of a metal plating film to constitute the optical fiber array 10. The joining strength is weak if the thickness of the metal plating film 12 is too thin. Production takes much time if the metal plating film is formed too thick and, therefore, the metal plating film is preferably formed in a 0.2 to 0.8mm, more preferably 0.3 to 0.5mm thickness. The need for the substrate having the fiber guide grooves precisely formed for each of the optical fiber array bodies is eliminated in this way and the mass production of the array at a low cost is possible. In addition, the drastic reduction of the size of the fiber fixing parts is possible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical fiber array in which a plurality of optical fibers are arranged and fixed in a row.

[Conventional technology]

When manufacturing an optical fiber array in which a plurality of optical fibers are arranged and fixed at predetermined intervals, a structure as shown in FIG. 8 is generally used. That is, on one side of the substrate 2,
Guide grooves 3 are formed at predetermined intervals by mechanical cutting, chemical etching, etc., optical fibers are placed in each of these guide grooves 3, and the optical fibers 1 are pressed against the wall surface of the guide grooves 3 using a presser plate 4. In this state, the gap is filled with resin adhesive 5 and fixed. As a result, optical fiber group 1.
... are fixed at an arrangement pitch according to the interval between the guide grooves 3 of the substrate 2.

[Problem that the invention seeks to solve]

The conventional optical fiber array structure described above requires a substrate with guide grooves for each component, and in order to maintain high precision in the depth and spacing of the guide grooves between grooves on a single substrate and between components, it is necessary to There were problems in that it required extremely expensive processing equipment and long hours of work, which were the bottlenecks in reducing prices.

In addition, in order to obtain the optical surface of the optical fiber end face after it is sandwiched and fixed between the substrate and the holding plate, a process of polishing the end face of the fiber array processor was necessary. [Means for solving the problem] The ends of a plurality of optical fibers from which the protective coating layer has been removed are brought into close contact between their sides or arranged at regular intervals, and an amorphous adhesive is applied directly to the ends to connect and fix them.

Low-melting point metal solder, metal plating material, organic resin, etc. can be used as the above-mentioned amorphous adhesive, but if the material of the optical fiber is glass or quartz, metal plating is recommended in terms of bonding strength and durability. Alternatively, it is desirable to use a low melting point metal solder. When using a metal knob material, it can be applied directly to the surface of the glass or quartz fiber.

When using metal solder, it is desirable to coat the peripheral surface of the fiber on the side where the fiber is to be joined with a base metal film in advance in order to ensure more secure adhesion.

In addition to placing the fibers in close contact with each other, the fiber arrangement
7. Dummy rod material should be made from the same material as the optical fiber of appropriate diameter.
A structure in which it is interposed between the eyes μ may also be adopted.

Alternatively, adjacent fibers may be connected and fixed with an adhesive with a fixed gap between them.

[For production]

According to the above structure, the conventional grooved substrate is not required, and the optical fiber array can be manufactured efficiently at low cost.

Further, after the optical fibers are arranged and fixed, cutting is performed at once so that the mirror surface portion of the optical fiber end face extends over almost the entire end face, thereby making it possible to omit the end face polishing step that was conventionally necessary.

〔Example〕

FIG. 1 is a perspective view showing an example of an optical fiber array according to the present invention, in which a glass optical fiber (bare wire) 11 is exposed by removing the protective coating Jii 2OA of the core wire 20 at the end.
A plurality of optical fibers (four in the illustrated example) are arranged in a line with their sides in close contact with each other, and these optical fibers 11 are attached at a certain distance from the end face using an amorphous adhesive 12 made of a metal plating film. are connected and fixed to form an optical fiber array 10.

If the thickness of the metal plating film 12 is too thin, the bonding strength will be weak, and if it is too thick, it will take time to manufacture.
The thickness is preferably within the range of 3 m to 0.5 m.

Although there is no particular restriction on the material of the plating film 12, a nickel plating material to which a small amount of phosphorus (P) is added is preferable because of its good adhesion to glass.

FIG. 2 shows a preferred method of making the array.

First, using an arraying jig 14 consisting of a V-grooved substrate and a holding plate similar to that shown in FIG. Leave a slight length protruding, and apply plating solution 2 to this protruding part.
Soak in 1. Prior to this immersion, the tip portion of the fiber that remains unplated is covered with a mask film 22 such as resist.

- As an example, using a fiber 11 with an outer diameter of 125μ, coat it with a resist film 22 to a position 15 mm from the tip, and then apply nickel phosphorus plating solution 2 to a position 30 mm from the tip.
1 and keep for about 1 day. As a result, a nickel phosphorus plating film 12 having a thickness of approximately 0.5 nm is obtained.

An optical surface can be easily formed on the end face of the fiber 11 by cutting it with an ordinary fiber cutter at a position approximately 15+w from the tip of the fiber, which is not coated with a plating film.

Another method for forming a non-plated part near the fiber tip is to apply hydrochloric acid after applying the plating film.

It is also possible to partially remove the plating film using sulfuric acid or the like.

FIG. 3 shows a second embodiment of the invention.

This example is an example of a structure in which 11 groups of optical fibers are bonded and fixed with an adhesive 12 with a certain gap between the side surfaces. For example, core wires 20 including a protective coating layer 20A are closely arranged, and exposed optical fibers are 11... The parts are connected and fixed by adhesive 12 in a natural state without converging.

The third embodiment shown in FIG. 4 is an example in which a group of optical fibers 11 are stacked in a plurality of layers in a tightly focused manner and are connected and fixed with an adhesive 12.

Various arrangement structures can be adopted outside the sides described above.

In any case, while maintaining a predetermined arrangement state using an arrangement jig consisting of a combination of a grooved substrate and a holding plate,
It can be easily manufactured by applying an amorphous adhesive to the optical fiber portion protruding from this jig and removing the jig after solidifying it.

Further, the above-described optical surface treatment of the end face of the optical fiber may be performed in advance before the connection and fixation, instead of being performed by cutting after the connection and fixation.

Further, by further plating a gold film to a thickness of about 0.5 μm on the surface of the Nisokerlin plating film 12, it becomes easy to mount the optical fiber array of the present invention on equipment by soldering.

As the plating film 12, other than nickel-phosphorus, various plating materials such as gold and chromium that have adhesive strength to glass can be used, but the nickel-phosphorus plating material has a thermal expansion coefficient of approximately 1.
30 x 10-', less than half that of epoxy resin adhesives, excellent thermal stability, and suitable for the present invention.

Furthermore, since the plating film can be formed at room temperature, there is no need to work at a high temperature of 200 to 400°C, unlike in the case of soldering, and there is also the advantage that thermal damage to the fiber can be avoided.

Next, FIGS. 5 and 6 show a fourth embodiment suitable for using low melting point metal solder as the irregularly shaped adhesive 12.
This will be explained based on the diagram.

FIG. 5 shows the pretreatment state of the optical fiber before joining with the solder 12.

As shown in the figure, a metal thin film 13 is coated by plating as a base layer for soldering on the side circumferential surface of a certain intermediate length of a bare optical fiber 11. - As an example, bare wire 1 with an outer diameter of 125 μm
1, a nickel-gold thin film 13 is uniformly plated to a thickness of 1 μm.

A predetermined number of optical fibers 11 each plated with a metal thin film 13 as described above are inserted into a groove 14A provided in an assembly jig 14 as shown in FIG. With the adjacent fibers placed and held in close contact with each other in a horizontal line, the gold-tin solder foil is reflowed on the plating film 13 to fix the fibers to each other.

After fixing the fiber, adjust the uneven length of the array tip.
In order to obtain an optical mirror surface on the end face of the fiber, a small scratch is made in the direction perpendicular to the axis of the fiber at the end of the solder-filled part using a commercially available ribbon fiber cutter. By developing these scratches, it is possible to obtain an end face with aligned cutting positions as shown in FIG.

The fiber arrangement pitch in the optical fiber array obtained by the above method is 12 times the outer diameter of the fiber and the thickness of the plating layer.
Although the diameter is 7 μm, an array with a smaller pinch can be produced by uniformly thinning the bare fiber under the plating layer by etching or the like.

FIG. 7 shows a fifth embodiment of the present invention.

This example is a structural example in which the arrangement pinch of the optical fibers is set to be equal to or larger than the fiber outer diameter, and a dummy member 15 having a predetermined outer diameter, such as a capillary, is interposed between each optical fiber 11, and these optical fibers 11 and A metal plating film 13 is previously applied to the side circumferential surface of the noble member 15 in the same manner as in the previous embodiment, and the metal plate 13 is closely bonded at this portion with a low melting point metal solder 12.

〔Effect of the invention〕

According to the structure of the present invention, there is no need for a substrate having precisely formed fiber guide grooves for each optical fiber array.
It can be mass-produced at low cost, and the size of the fiber fixing part can be significantly reduced compared to conventional structures.

Furthermore, by finishing the fiber end face only by cutting, the polishing process for parts can be reduced.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing one embodiment of the present invention, FIG. 2 is a sectional view showing one example of a method for manufacturing an optical fiber array according to the present invention, and FIG. 3 is a perspective view showing another embodiment of the present invention. A perspective view showing,
FIG. 4 is a perspective view showing another embodiment of the present invention, FIGS. 5 and 6 are perspective views showing another example of a method for manufacturing an optical fiber array according to the present invention, and FIG. 7 is a perspective view showing another embodiment of the present invention. FIG. 8 is a perspective view showing still another embodiment, and a front view showing a conventional optical fiber array structure. 10... Optical fiber array, 11... Optical fiber,
12... Irregular adhesive material, 13... Soldered metal film for base, 14... Assembly jig, 15... Dummy bar material for adjusting fiber arrangement row pitch, 20... Core wire, 20
A...Protective coating layer, 21... Plating solution, 22...
mask membrane. Figure 3 Figure 5 Figure 3 Figure 5 (Conventional example)

Claims (1)

[Claims] 1) The ends of a plurality of optical fibers from which the protective coating layer has been removed,
An optical fiber array characterized in that the sides are arranged in close contact with each other or at regular intervals, and the portions are connected and fixed with an amorphous adhesive. 2) The optical fiber array according to claim 1, wherein the optical fibers are glass or quartz fibers, and the irregular adhesive material is a metal plating film. 3) The optical fiber array according to claim 1, wherein a dummy rod for adjusting the arrangement pitch is interposed between the optical fibers.