GB1576459A

GB1576459A - Optical fibres connectors

Info

Publication number: GB1576459A
Application number: GB1778877A
Authority: GB
Original assignee: Standard Telephone and Cables PLC
Current assignee: STC PLC
Priority date: 1977-04-28
Filing date: 1977-04-28
Publication date: 1980-10-08
Also published as: FR2389148A1; FR2389148B1; BR7802468A

Description

(54) iMPROVEMENTS IN ORRELATING TO OPTICAL FIBRE CONNECTORS (71) We, STANDARD TELEPHONES AND CABLES LIMITED, a British Company, of 190 Strand, London W.C.2, England, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: - This invention relates to optical fibre connectors, and especially to -such connectors which are of the hermaphroditic type.

One of the techniques now current for connecting optical fibres uses ferrules to terminate each of the optical fibres to be connected. 'In such ' a ferrule the end of the fibre is accurately located at the centre of the ferrule, for instance by' the use. of a watch jewel so that when two such ferrules have their ends abutting accurate alignment of the ferrules aligns the fibres. Hence light passes from one optical fibre to the other optical fibre with low loss of light.

The alignment of the ferrules is achieved by the use of for example precision bore guides, or deformable tubes or helical springs.

The above techniques require the alignment guides to be housed in one half of the connector. However, for some applications it is desirable for the connector shells to be hermaphroditic. If an even number of fibres are to be connected using a multi-way connector shell, half the alignment guides can be housed in each cell to give hermaphrodicity. However, such an approach is not suitable for use where each connector element carries an odd number of fibres.

An object of the invention is to provide a connector arrangement for optical fibres which is truly hermaphroditic.

According to the invention there is provided a connector element for optical fibres, which includes a ferrule with a substantially flat end face in which the fibre is terminated, the fibre end lying in the axis of the ferrule, a block having a V-groove in which the ferrule rests in such a way that the V-groove extends beyond the end face of the ferrule, and a clamping spring on the opposite side of the element frorn,the V-groove, the arrangement being such that when two such elements are fitted together the ferrule end faces abut and the V-gtooves are on different sides of the ferrules,, só that each said ferrule is in both 'said..Vr grooves, and that each of the two clamping springs then acts on the V-groove block of the other element to retain the two con- nector elements in engagement.

An embodiment of the inventian;.:will now be described with reference to the drawing accompanying the Provisional Specification, in which Fig. 1 shows one connector element embodying the invention, Fig. 2 shows how two elements each as shown in Fig. 1 fit together, and Fig. 3 is a cross-section of the two elements when fitted together.

In Fig. 1, the fibre 1 is terminated by a ferrule 2, the fibre being centrally located therein. The coating on the fibre is removed for a short distance near its end, and the bared fibre located in the central hole of a watch jewel mounted near the right-hand end of the ferrule. The fibre is fixed in place in the ferrule with a potting medium, and the fibre end is ground fiat. The back end of the ferrule has a larger diameter shoulder 3 which is located in a recess in a support block 4, there being a compression spring 5 as shown to urge the ferrule rightwards. As will be seen later this spring serves to provide the optical equivalent of contact pressure.

The support block 4 has an extension 5 which is formed with a V-groove 6 which receives the ferrule 2, and on its outer face this extension 4 has a raised portion 7. On the block 4 but on the opposite side of the ferrule 2 from the grooved extension 5 there is a clamping spring 8.

Fig. 2 shows how two terminations each of which is as in Fig. 1 fit together, and it is felt that no description thereof is needed after the description given of Fig. 1. Fig.

3 is a cross-section of the two terminations when fitted together.

As shown each of the grooved blocks has its outer end chamfered to assist engagement; Each V-groove assembly may have a slight degree of float, to assist in ensuring accurate alignment of the ferrule.

It will be appreciated that multi-way connectors can be assembled in which each connector element has a number (odd or even) of terminations such as that shown in Fig. 1.

WHAT WE CLAIM IS: 1. A connector element for optical fibres, which includes a ferrule'with a substantially flat end face in which the fibre is terminated, the fibre end lying in the axis of the ferrule, a block having a V-groove in which' the ferrule rests in such a way that the V-groove extends beyond the face of the ferrule, and a clamping spring on ,the 'opposite side of the element from the 'V-groove, the arrangement being such that when two such.elements are fitted together the' ferrule end faces abut and the Vgrooves are on different sides of the ferrules, so that each said ferrule is in both said V-grooves, and that each of the two clamping springs then acts on the Vgroove block of the other element to retain the two connector elements in engagement.

2. An element as claimed in claim 1, in which said ferrule has a shoulder at its nonengagement end which is of larger diameter than the body of the ferrule, in which said block has a cylindrical recess for the re ception of the ferrule which projects therefrom into the V-groove, and in which said recess contains a spring which urges the shoulder of the ferrule against an inner wall of the recess.

3. An element as claimed in claim 1 or 2, in which 'said clamping spring is a leafspring having one of its ends secured at one end to the block, the other end thereof being biased towards the ,element's Vgroove; and in which 'on the outer surface groove, and in which on the'outer surface of the V-groove there is a raised portion for co-opera,tion with a said clamping spring.

4. A' connector element for optical fibres, súbstantially as described with reference to the drawing accompanying the Provisional Specification.

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. As shown each of the grooved blocks has its outer end chamfered to assist engagement; Each V-groove assembly may have a slight degree of float, to assist in ensuring accurate alignment of the ferrule. It will be appreciated that multi-way connectors can be assembled in which each connector element has a number (odd or even) of terminations such as that shown in Fig. 1. WHAT WE CLAIM IS:

1. A connector element for optical fibres, which includes a ferrule'with a substantially flat end face in which the fibre is terminated, the fibre end lying in the axis of the ferrule, a block having a V-groove in which' the ferrule rests in such a way that the V-groove extends beyond the face of the ferrule, and a clamping spring on ,the 'opposite side of the element from the 'V-groove, the arrangement being such that when two such.elements are fitted together the' ferrule end faces abut and the Vgrooves are on different sides of the ferrules, so that each said ferrule is in both said V-grooves, and that each of the two clamping springs then acts on the Vgroove block of the other element to retain the two connector elements in engagement.