JPS6132644B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a grooved member for fixing optical fibers used for multi-core connection of optical fibers.

When connecting optical fibers, it is necessary to precisely align the extremely thin optical fibers.
In practice, it is necessary to establish a connector and a connection method that can connect a large number of optical fibers at once with high accuracy and at low cost with high reliability.

As such a multi-fiber connection, there is a method in which optical fibers are fixed and held in multiple grooves provided on the plane of the substrate. In this method, extremely high accuracy is required for groove processing because variations in groove shape directly affect the mutual axis misalignment of the optical fiber strands to be connected. Furthermore, the difference in materials between the optical fiber and the substrate causes deterioration of connection characteristics due to a difference in coefficient of thermal expansion with respect to temperature changes. Therefore, the material of the substrate and the groove processing method are extremely important.

From the standpoint of improving reliability, which is important in practice, it is desirable to use a glass substrate made of the same material as the optical fiber (glass). FIGS. 1 and 2 are perspective views for explaining an example of a conventional fixing groove manufacturing method using glass. Figure 1 shows glass substrate 1
A method is shown in which a diamond blade 2 is placed on the plane of the groove 3 and the groove 3 is cut. FIG. 2 shows a method of constructing the groove 5 by laminating together a large number of glass pieces 4 that have been polished at appropriate angles. However, such a method requires advanced technology, is not suitable for mass production, and is expensive, so the major disadvantage is that it is impractical.

Examples of methods for manufacturing the fixing groove using materials other than glass include metal cutting methods and plastic injection molding methods. However, both methods require advanced technology for groove processing, and since the materials are different from the optical fiber, there remains an inherent problem in terms of reliability after connection.

As described above, the conventional method for manufacturing fixed grooves for multi-fiber connections cannot be said to be a practical method that satisfies all of the requirements of workability, mass production, economy, and reliability after connection.

In order to eliminate these drawbacks, the present invention arranges a plurality of glass rods having the same circular cross section in close contact with each other in the longitudinal direction, and
This method provides a highly precise, mass-producible, and economical method for manufacturing a grooved member for fixing optical fibers using an extremely simple method of stretching while heating and cutting to a desired length. will be explained in detail.

FIG. 3 shows an embodiment of the invention. First, as shown in a, the glass rod 8 has the same circular cross section.
are arranged closely together with their outer peripheries touching in the longitudinal direction. At this time, grooves of the same shape are formed between adjacent glass rods 8. Next, as shown in b, while heating the glass rod 8, tension is applied in the longitudinal direction to reduce the cross section of the stretched glass rod 8 and to fuse the glass rods together.

It is effective to cut out the glass rod 8 as a starting material from one long glass round rod, and a large number of glass rods with the same cross-sectional shape can be obtained.

In the process of stretching while heating, the heating temperature and stretching speed are adjusted to reduce the force that causes the glass rods to overlap due to surface tension as they are heated and softened.
By substantially balancing the forces that try to pull apart the glass rods at the portion where the diameter shrinks, it becomes possible to uniformly stretch a large number of glass rods arranged. Such heating and stretching conditions can be easily found if, for example, Pyrex glass is used, whose viscosity decreases slowly with respect to heating temperature.

Diameter reduction by stretching the glass rod can be uniformly achieved to a reduction rate of about 1/10, and this diameter reduction also reduces dimensional accuracy. This means that if a glass rod with a dimensional accuracy of ±10 μm is used as a starting material, an accuracy of ±1 μm will be obtained after the diameter is reduced to 1/10. Here, dimensional accuracy refers to the variation in diameter in the longitudinal direction of the same glass rod or the deviation in diameter between different glass rods, but more specifically, it refers to the variation in the diameter of the same glass rod in the longitudinal direction, and more specifically, the difference in the diameter of the optical fiber when it is fixed to the obtained member. It appears as positional accuracy. In the method of the present invention, the glass rods are fused to each other as they are stretched, so that the bottom of the fixing groove formed between the glass rods undergoes a slight change in shape. However, since the optical fiber fixed in this groove is in line contact with the glass rod forming the fixing groove at the outer periphery of each other, slight changes in the shape of the bottom of the fixing groove will affect the accuracy of the fixing position of the optical fiber. does not affect

Although the method for linearly arranging glass rods has been described above, the same applies to a method for three-dimensionally bundling a large number of glass rods. For example, by bundling seven glass round rods and stretching them while heating, six highly precise grooves of the same shape can be obtained between adjacent outer round rods.

As described above, in the method of manufacturing a grooved member for fixing optical fibers according to the present invention, a highly accurate member can be obtained from a single glass rod in an extremely simple manner, and is also extremely efficient in terms of mass production and economy. It is excellent.

As explained above, the method for manufacturing the grooved member for fixing optical fibers of the present invention does not require advanced technology such as directly machining fixing grooves with high precision as in the past, and it can be done from a single glass rod. Since high-precision fixing grooves can be mass-produced using an extremely simple method, low-loss and inexpensive connectors can be provided using the members obtained by the manufacturing method of the present invention. Furthermore, since this member is made of glass like the optical fiber, it has the advantage of providing a practical connector with excellent reliability after connection.

[Brief explanation of the drawing]

Figures 1 and 2 show an example of a conventional method for manufacturing fixed grooves for multi-core connections, and Figure 1 is an explanatory diagram of the cutting method;
FIG. 2 is an explanatory diagram of the laminating method, and FIG. 3 is a diagram showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1...Glass substrate, 2...Diamond blade for groove cutting, 3...Cut groove, 4...Glass piece for groove formation, 5...Groove formed by lamination,
8...Glass round rod, 8'...Reduced glass rod.

Claims (1)

[Claims] 1. A process of arranging a plurality of glass rods having the same circular cross section in close contact with each other in the longitudinal direction with their outer circumferences touching, and heating the glass rods,
Manufacture of a grooved member for fixing an optical fiber, comprising a step of fusing the glass rod while pulling it in the axial direction and reducing the cross section of the glass rod, and a step of cutting the fusing member to a desired length. Method.