GB2162838A - Method of making fibre endfaces - Google Patents

Abstract

Various methods of making fibre endfaces which are perpendicular to the longitudinal axis of an optical fibre are disclosed. According to one method, the fibre (1) is chucked in such a way in two holders 2, 3 and 4, 5 that the fibre section (7) between the holders, is free from torsional stress, or is freed from torsional stress by being locally heated up to the melting point after having been chucked in any suitable way. Thereafter, the fibre is scratched and torn apart by the action of an axial tensile force (9). <IMAGE>

Description

SPECIFICATION Method of making fibre endfaces This invention relates to a method of making fibre endfaces which are perpendicular to the longitudinal axis of an optical fibre, of the kind in which a fibre is cut by being scratched and subjected to an axial tensile stress, in which the fibre endface is produced in that particular section of the fibre lying between two holding devices in which the fibre is non-positively chucked.

A device for carrying out such a method is disclosed in DE-GM 82 13 866. In this device, the fibre is chucked in two holders and is scratched at one point between the two holders with the aid of a scratching tool. When subjected to a tensile stress, the fibre is torn apart at the scratched point. Only a small number of all fibre endfaces produced in this way is perpendicular to the fibre axis.

It is an object of the invention to provide a method which can be relied upon to produce fibre endfaces which are perpendicular to the fibre axis.

According to the invention in its broadest aspect, a method of making fibre endfaces of the kind referred to is characterised in that the fibre is chucked free from torsion, or is freed from torsional stresss prior to being cut, in the section between the holding devices.

The methods according to the invention only involve a slight additional investment compared with conventional methods. They are of particular advantage in cases where several fibre endfaces have to be produced simultaneously for establishing multiple spliced connections.

Embodiments of the invention will now be described by way of example with reference to Figures 1 and 2 of the accompanying drawings, in which: Figure 1 shows the steps of the method according to a first embodiment, and Figure 2 shows the steps of the method according to a second embodiment.

In the method according to Figure 1 a fibre 1 at whose end a fibre endface is to be produced which is perpendicular to the fibre axis, is chucked in a first holder 2, 3. This holder, for example, contains a plate 2 with a groove into which the fibre is placed, and a hold-down device 3 by'which the fibre is chucked. A fibre section 6 is chucked in a second holder 4, 5. The holders are disposed in such a way that the longitudinal axes of the fibre section 6 and of the fibre 1 are in a straight line (Figure 1a). The fibre section 6 as well as the fibre 1 in its section 7 are completely free from torsional stress, because each of them is only chucked in one holder. In a next step, both the fibre 1 and the fibre section 6 are fused to form the fibre 10 which is free from torsion within a section 8 (Figure 1b).

In the following step, this fibre 10 is scratched with the aid of a scratching tool 9 between the fused joint and the holder 2, 3 (Figure inc). In the last step, the holders 2, 3 and 4, 5 are pulled apart in such a way that only axial tensile stresses occur within the fibre, causing the fibre 10 to be torn at the scratched point (Figure 1d). In this way, fibre endfaces 11 are obtained which are exactly perpendicular to the longitudinal axis of the fibre, and a fibre section 6' which can be further used instead of the fibre section 6 in the course of producing further fibre endfaces.

The individual steps of a further method are shown in Figure 2. In referring to Figure 1, identical parts are indicated by the same reference numerals. The fibre 1 is chucked in the two holders 2, 3 and 4, 5 (Figure 2a), and is thereafter momentarily heated up to the melting point somewhere between the two holders (Figure 2b). This eliminates any torsional stresses within the section 8 of the fibre. The following steps, namely the scratching and the tearing of the fibre are carried out as described hereinbefore (Figure 2c, d).

According to a third method, the fibre is chucked a few centimeters away from its end in a suitable way in a first holder. After that, the end of the fibre is placed into a liquid, such as tin solder or an adhesive which solidifies thereafter. Owing to this kind of chucking, torsional stresses, from the beginning, are prevented from occuring within the section between the holders, because owing to the solidification of the liquid, neither axial nor tangential forces are exerted upon the fibre. The scratching and tearing of the fibre is effected thereafter, in a manner known per se.

1. A method of making fibre endfaces which are perpendicular to the longitudinal axis of an optical fibre, of the kind in which a fibre is cut by being scratched and subjected to an axial tensile stress, in which the fibre endface is produced in that particular section of the fibre lying between two holding devices in which the fibre is non-positively chucked, characterised in that the fibre is chucked free from torsion, or is freed from torsional stress prior to being cut, in the section between the holding devices.

2. A method as claimed in claim 1, characterised in that the fibre is chucked in a first holding device, and one fibre section is chucked in a second holding device, and that thereafter both the fibre and the fibre section are fused to one another.

3. A method as claimed in claim 1, characterised in that the fibre, in a first step, is chucked in the holding devices and that, in a second step, the fibre is momentarily heated up to the melting point at a point lying between the two holding devices.

4. A method as claimed in any one of the preceding claims, characterised in that the fibre is soldered or glued to at least one of the holding devices.

5. A method of making fibre endfaces substantially as described with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Method of making fibre endfaces This invention relates to a method of making fibre endfaces which are perpendicular to the longitudinal axis of an optical fibre, of the kind in which a fibre is cut by being scratched and subjected to an axial tensile stress, in which the fibre endface is produced in that particular section of the fibre lying between two holding devices in which the fibre is non-positively chucked. A device for carrying out such a method is disclosed in DE-GM 82 13 866. In this device, the fibre is chucked in two holders and is scratched at one point between the two holders with the aid of a scratching tool. When subjected to a tensile stress, the fibre is torn apart at the scratched point. Only a small number of all fibre endfaces produced in this way is perpendicular to the fibre axis. It is an object of the invention to provide a method which can be relied upon to produce fibre endfaces which are perpendicular to the fibre axis. According to the invention in its broadest aspect, a method of making fibre endfaces of the kind referred to is characterised in that the fibre is chucked free from torsion, or is freed from torsional stresss prior to being cut, in the section between the holding devices. The methods according to the invention only involve a slight additional investment compared with conventional methods. They are of particular advantage in cases where several fibre endfaces have to be produced simultaneously for establishing multiple spliced connections. Embodiments of the invention will now be described by way of example with reference to Figures 1 and 2 of the accompanying drawings, in which: Figure 1 shows the steps of the method according to a first embodiment, and Figure 2 shows the steps of the method according to a second embodiment. In the method according to Figure 1 a fibre 1 at whose end a fibre endface is to be produced which is perpendicular to the fibre axis, is chucked in a first holder 2, 3. This holder, for example, contains a plate 2 with a groove into which the fibre is placed, and a hold-down device 3 by'which the fibre is chucked. A fibre section 6 is chucked in a second holder 4, 5. The holders are disposed in such a way that the longitudinal axes of the fibre section 6 and of the fibre 1 are in a straight line (Figure 1a). The fibre section 6 as well as the fibre 1 in its section 7 are completely free from torsional stress, because each of them is only chucked in one holder. In a next step, both the fibre 1 and the fibre section 6 are fused to form the fibre 10 which is free from torsion within a section 8 (Figure 1b). In the following step, this fibre 10 is scratched with the aid of a scratching tool 9 between the fused joint and the holder 2, 3 (Figure inc). In the last step, the holders 2, 3 and 4, 5 are pulled apart in such a way that only axial tensile stresses occur within the fibre, causing the fibre 10 to be torn at the scratched point (Figure 1d). In this way, fibre endfaces 11 are obtained which are exactly perpendicular to the longitudinal axis of the fibre, and a fibre section 6' which can be further used instead of the fibre section 6 in the course of producing further fibre endfaces. The individual steps of a further method are shown in Figure 2. In referring to Figure 1, identical parts are indicated by the same reference numerals. The fibre 1 is chucked in the two holders 2, 3 and 4, 5 (Figure 2a), and is thereafter momentarily heated up to the melting point somewhere between the two holders (Figure 2b). This eliminates any torsional stresses within the section 8 of the fibre. The following steps, namely the scratching and the tearing of the fibre are carried out as described hereinbefore (Figure 2c, d). According to a third method, the fibre is chucked a few centimeters away from its end in a suitable way in a first holder. After that, the end of the fibre is placed into a liquid, such as tin solder or an adhesive which solidifies thereafter. Owing to this kind of chucking, torsional stresses, from the beginning, are prevented from occuring within the section between the holders, because owing to the solidification of the liquid, neither axial nor tangential forces are exerted upon the fibre. The scratching and tearing of the fibre is effected thereafter, in a manner known per se. CLAIMS

1. A method of making fibre endfaces which are perpendicular to the longitudinal axis of an optical fibre, of the kind in which a fibre is cut by being scratched and subjected to an axial tensile stress, in which the fibre endface is produced in that particular section of the fibre lying between two holding devices in which the fibre is non-positively chucked, characterised in that the fibre is chucked free from torsion, or is freed from torsional stress prior to being cut, in the section between the holding devices.

2. A method as claimed in claim 1, characterised in that the fibre is chucked in a first holding device, and one fibre section is chucked in a second holding device, and that thereafter both the fibre and the fibre section are fused to one another.

3. A method as claimed in claim 1, characterised in that the fibre, in a first step, is chucked in the holding devices and that, in a second step, the fibre is momentarily heated up to the melting point at a point lying between the two holding devices.

4. A method as claimed in any one of the preceding claims, characterised in that the fibre is soldered or glued to at least one of the holding devices.

5. A method of making fibre endfaces substantially as described with reference to the accompanying drawings.