WO2009016396A2

WO2009016396A2 - Improvements in or relating to optical fibre management

Info

Publication number: WO2009016396A2
Application number: PCT/GB2008/050566
Authority: WO
Inventors: Jan Watte; Valere Buekers; Freddy Vanwinkel; Walter Mattheus
Original assignee: Tyco Electronics Raychem Nv; Tyco Electronics Uk Ltd
Priority date: 2007-07-27
Filing date: 2008-07-14
Publication date: 2009-02-05
Also published as: WO2009016396A3; GB0714629D0

Abstract

An optical fibre connector for forming a mechanical splice between first and second optical fibres the connector comprising a base part (1) and a lid part (2) arranged to clamp the optical fibres therebetween, and wherein the base and lid are resiliently biased towards each other by biasing means (4) at least partly incorporated in the lid and/or the base.

Description

IMPROVEMENTS IN OR RELATING TO OPTICAL FIBRE MANAGEMENT

The present invention relates to optical fibre connectors. In particular, the invention relates to optical fibre connectors for forming mechanical splices between optical fibres.

Optical fibre joints in which fibres are spliced together by mechanical means are well known. In order to ensure the production of a satisfactory mechanical splice, having low optical losses, the end faces of the fibres may be prepared for splicing. Such preparations may simply be the production of an angled end face on each of the fibres, which has the advantage of minimising undesirable back reflections. Splicing two fibres having such angled faces, those faces being optimally aligned and orientated such that the end faces are in intimate contact with one another, will generally produce a mechanical splice having low optical losses and minimal back reflections.

A number of optical fibre connectors for forming mechanical splices are known. An example of one type of known mechanical splice connector is disclosed in US Patent No. 4,946,249. The connectors disclosed in that document each comprise a pair of housing halves which, when assembled together, provide a housing having a bore extending therethrough to accommodate the fibres being spliced. Optical fibres generally have coatings which need to be stripped away from the end sections of the fibres before those stripped sections are butted together to form the splice. The bore in the connector housing is generally wider at the ends of the housing to accommodate the coated sections of the fibres, and narrower in the middle of the housing to accommodate the bare stripped fibres. Because there is more than one typical thickness of an optical fibre coating, some of the connector housings have differing bore diameters at opposite ends of the housing, so that dissimilar sizes of fibres can be spliced together. There is also a respective connector housing for splicing together each size of optical fibre.

US Patent No. 5,963,699 discloses optical fibre mechanical splice connectors comprising a base and a lid between which the spliced fibres are clamped by means of an external spring clamp that holds the base and the lid together. The lid is formed from three separate sections, i.e. a single middle section for clamping both stripped bare portions of the spliced fibres, and two end sections for clamping each of the two coated fibre portions. The spring clamp is divided into three sections corresponding to the three sections of the lid, so that the clamping force can be adjusted for each lid section independently of the other sections. It is an object of the present invention to provide an improved optical fibre mechanical splice connector. Accordingly, the present invention provides an optical fibre connector for forming a mechanical splice between first and second optical fibres, the connector comprising a base part and a lid part arranged to clamp the optical fibres therebetween, and wherein the base and lid are resiliently biased towards each other by biasing means at least partly incorporated in the lid and/or the base. Such an arrangement allows the production of a simple and economical optical mechanical splice connector. Integrally resiliently biasing one of the base and lid part of the connector towards the other negates the difficulty of handling a separate spring or clamping means with the other parts of the connector.

The biasing means may be incorporated by forming it as an integral continuation of the lid and/or base, for example a resilient living hinge.

The biasing means may be incorporated by adhering, rivetting, or otherwise securing part(s) of a suitably shaped spring member to a surface of the lid and/or of the base, or by embedding a suitably shaped spring member wholly or partly in one or both of the lid and base, for example by overmoulding the lid and/or the base around the relevant part(s) or whole of the spring member.

The optical fibre connector may form a splice between first and second optical fibres, a portion of those optical fibres having been stripped of coatings.

The parts of the optical fibre connector may both be formed from a plastics material. Only one of the parts of the optical fibre connector may be formed from a plastics material. The lid and/or the base may be moulded, formed, or extruded from plastics material having suitable resilient properties. The lid and/or the base may be substantially wholly made of a suitable resilient plastics material.

One of both parts of the optical fibre connector may have a substantially U-shaped profile, and each part may, in use, retain the other part of the connector in a predetermined position in relation to itself by means of a clamping action. The two connector parts may include cooperating portions to aid alignment. The lid and/or the base of the optical fibre connector may further include a suitably shaped spring member. That spring member may be a resilient metal portion. That resilient metal portion may provide reinforcement to the clamping action of the lid and/or base. The resilient metal portion may be placed or located in the region of a weakened portion of the relevant connector part. The resilient metal portion may be a substantially planar element and may be provided in the region of a stress or hinge point of the lid and/or base.

The resilient metal portion may take the form of a substantially U-shaped spring clamp. The resilient metal portion may take the form of a substantially planar metal element. The substantially planar element or spring clamp may be shaped or thinned in a hinged region. Such shaping or thinning allows for increased resilience, reduces metal fatigue and also allows for increased flexibility in relation to the clamping strength applied to the optical fibres.

Provision of a hinge point allows for controllable hinge and clamping function of the connector.

The resilient metal portion may be overmoulded with a plastics material. Plastics material may be "riveted" to the resilient metal portion to form a base and a lid part. Overmoulding and riveting both allow a secure bond to be formed between the resilient metal portion and the lid and/or base. Suitable metals for the resilient metal portion include, for example, a CrNi stainless steel alloy. That metal may be overmoulded by suitable plastics materials, including polyphenylene sulphide (PPS) and liquid crystal polymers (LCP)

The resilient metal portion may serve to provide all of the resilient bias of the lid and/or base part, alternatively the lid and/or base may be formed from a material which is itself resilient, in which case the biasing means is incorporated by forming it as an integral continuation of the lid and/or base, for example, as a resilient living hinge.

The connector may include at least two clamping sections, those clamping sections may be arranged to clamp directly onto the portion of stripped optical fibre, and such that the first optical fibre may be clamped by a clamping section of the connector independently of the second optical fibre. Such an arrangement allows a first optical fibre to be installed in the mechanical splice connector independently of a second optical fibre. The second optical fibre may be spliced with the first fibre at a later time, the first fibre being securely clamped with respect to the connector so as to be substantially undisturbed by the addition of the second optical fibre.

The base part or the lid part of an optical fibre connector according to the present invention may be configured to form a plurality of clamping sections. The connector may include both clamping section for clamping the bare fibres as described above and may further include additional independent clamping sections arranged to clamp the coated portions of the fibres.

Some of the clamping sections may be arranged such that a first optical fibre may be clamped by at least one of the clamping sections independently of the second optical fibre. Such an arrangement allows clamping of the first fibre against rotational and axial movement with respect to the connector when subsequent clamping or unclamping of the second fibre occurs.

The connector may include at least three primary, bare fibre clamping sections. One of those clamping sections may clamp both first and second bare fibres. A second of those clamping sections may be arranged to clamp only the first bare fibre, a third of those clamping sections may be arranged to clamp only the second bare fibre.

At least one of the base part and lid part of the connector may include a bore configured to receive the optical fibres. The bore may be of varying diameter along the connector body. The bore may, for example, be of reduced diameter in the region intended to clamp the bare fibre. The bore may also be of increased diameter in the region intended to clamp the coated fibre.

The bore may also act as an alignment means. The optical fibres may be sufficiently aligned by the alignment means to form a splice in which optical losses are reduced to an acceptable level. In particular, the bore may be dimensioned such that in the clamping sections for the stripped bare fibres, the fibres form a tight fit within the bore. The bore may take the form of a groove in one or other of the base part or the lid part. The bore may be a V-groove or a U-groove.

Some preferred embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings in which: Figure 1 illustrates, in cross-section, the components of an optical fibre connector according to a first embodiment of the present invention;

Figure 2 illustrates various alternative forms of the hinge region of the biasing means of the connector shown in Figure 1 ; Figure 3(a) shows, in cross-section, the assembled components of an optical fibre connector similar to that of Figure 1;

Figure 3(b) is a perspective view of an assembled connector similar to that shown in Figure 1;

Figure 4 illustrates, in cross-section, the components of an optical fibre connector according to a second embodiment of the present invention; Figure 5 is an enlarged view, in cross-section, of the region marked "A" in Figure 4;

Figure 6(a) illustrates, in cross-section, the components of an optical fibre connector according to a third embodiment of the present invention;

Figure 6(b) is a perspective view of an assembled connector in accordance with the third aspect of the present invention; Figures 7(a) and (b) illustrate schematically a means of joining elements to form a connector in accordance with a fourth embodiment of the present invention; and

Figure 7(c) is a perspective view of an assembled connector in accordance with the fourth embodiment of the present invention.

Figure 1 illustrates, in cross section, the components of an optical fibre connector according to a first embodiment of the present invention. The connector comprises a base part 1 and a lid part 2 arranged to clamp optical fibres therebetween. The base part 1 and lid part 2 are resiliently biased towards each other by biasing means 4 partly incorporated in the lid part . The lid part 2 is placed over and around the base part to form an assembled connector, divided in two along its length. The base part 1 includes a longitudinal V-shaped channel 3. When the connector is assembled, that longitudinal channel defines a bore that extends though the connector body. The bore is suitable, in use, for accommodating first and second optical fibres spliced in the connector. The lid part 2 takes the form of an element resiliently biased towards the base part. The biasing means is, in this embodiment, a substantially U-shaped metal spring clamp 4 the spring clamp has an overmoulded plastics portion 5. The spring clamp 4 has a shaped portion 6. That shaped portion acts as a hinge.

The base part 1 and lid part 2 include cooperating portions 7, 8 to aid alignment and retain, in use, the two parts of the connector in a predetermined position in relation to one another. Figure 2 illustrates various alternative forms of the hinge region of the connector of Figure 1. Figure 2(a) and 2(b) show hinge regions in which the metal is shaped to protrude outwards. Figure 2(c) and 2(d) show hinge regions in which the metal is shaped to protrude inwards. Figure 2(e) shows a hinge region in which the metal is thinned.

Figure 3(a) shows, in cross-section, the assembled components of an optical fibre connector similar to that of Figure 1. Figure 3(b) is a perspective view of an assembled connector similar to that shown in Figure 1. It can be seen that the base part 1 is retained in position within the lid part 2 as a result of the nature of the lid part being resiliently biased towards the base part and a retaining portion 7 provided on the lid part 2 of the connector. In this embodiment, the resilient bias of the lid part 2 is provided by a substantially U-shaped metal spring clamp 4. That spring clamp 4 has an overmoulded plastics portion 5. The base part 1 includes a longitudinal V-shaped channel 3. When the connector is assembled, as shown that longitudinal channel defines a bore 9 that extends though the connector body. The bore is suitable, in use, for accommodating first and second optical fibres spliced in the connector.

The base part and lid part of the optical fibre connector are configured to form a plurality of clamping sections 10 (a)-(e). In the embodiment shown the lid part is divided into five clamping sections. The connector includes both clamping sections for clamping the bare fibres and additional independent clamping sections arranged to clamp the coated portions of the fibres.

The clamping sections are arranged such that a first optical fibre may be clamped by at least one of the clamping sections independently of the second optical fibre. Such an arrangement allows clamping of the first fibre against rotational and axial movement with respect to the connector when subsequent clamping or unclamping of the second fibre occurs.

Figure 4 illustrates, in cross-section, the components of an optical fibre connector according to a second embodiment of the present invention. Where appropriate, the numbering conventions applied to Figures 1 to 3 have been adhered to. In this embodiment, the lid part 2 is formed from a suitable resilient plastics material. The hinge region of the lid part 2 is indicated generally by the reference letter "A". Figure 5 is an enlarged view, in cross-section, of the region marked "A" in Figure 4. The plastics material is thinned in the "hinge" area to allow for movement of the lid part when engaging with the base part. Also provided in that area is a metal reinforcement plate 11. The reinforcement plate 11 acts as a biasing means and is wholly incorporated in the lid part. The metal plate 11 may be substantially planar as shown in Figures 4 and 5, but may, for example, be shaped or thinned in a manner similar to the hinge portions of the metal spring clamp 4, as shown in Figure 2.

Figure 6(a) illustrates, in cross-section, the components of an optical fibre connector according to a third embodiment of the present invention.

Figure 6(b) is a perspective view of an assembled connector according to the third aspect of the present invention. Again, where appropriate, previously established numbering conventions have been adhered to. In this embodiment, the lid part 2 is formed solely from a resiliency biased element made from a suitable plastics material. The lid part 2 thus takes the form of a U-shaped clamp made of plastics material. It is moulded or extruded and includes a thinned hinge section 6. That thinned section is an integral continuation of the lid part and can be described as a resilient living hinge. The base part also takes the form of a generally U-shaped member. As described in relation to Figure 3, the base part 1 is retained in position within the lid part 2 by a retaining portion 7 provided on the lid part 2 of the connector. The base part 1 includes a longitudinal V-shaped channel 3. When the connector is assembled that longitudinal channel defines a bore 9 that extends though the connector body. The bore is suitable, in use, for accommodating first and second optical fibres spliced in the connector.

Figures 7(a) and (b) illustrate schematically a means of joining elements in accordance with a fourth embodiment of the present invention. Figure 7(a) shows, in cross-section, the components of an optical fibre connector similar to that of Figure 1, prior to a plastics riveting process. Protrusions 12 provided on a plastics base part and lid part are located in cooperating holes 13 provided on a biasing means in the form of a substantially U-shaped spring clamp 4. In this embodiment the biasing means is at least partially incorporated in both the base part and the lid part. Both lid part and base part are attached to the resilient, substantially U-shaped, metal element 4. It will thus be understood that the lid part and the base part are integrally resiliently biased towards one another. It will also be understood that it is possible to simply attach the lid part to the metal spring 4, thereby arriving at an arrangement similar to those shown in previous Figures. Figure 7(b) shows, in cross- section, the assembled connector shown in Figure 7(a). The application of heat and pressure to the protrusions 12 causes them to deform and form a plastics material "rivet" 14 to hold the lid part and base part to the metal element 4.

In general, the lid and base parts of a connector in accordance with the present invention may be opened for the placing of optical fibres by insertion of an appropriate wedge from the rear or from the side of the connector.

Claims

1. An optical fibre connector for forming a mechanical splice between first and second optical fibres the connector comprising: a base part and a lid part arranged to clamp the optical fibres therebetween, and wherein the base and lid are resiliently biased towards each other by biasing means at least partly incorporated in the lid and/or the base.

2. An optical connector according to claim 1, wherein the biasing means is incorporated by forming it as an integral continuation of the lid and/or of the base.

3. An optical connector according to claim 2 wherein the biasing means is incorporated as a resilient living hinge.

4. An optical connector according to claim 1, wherein the biasing means is incorporated by adhering, rivetting, or otherwise securing part(s) of a suitably shaped spring member to a surface of the lid and/or of the base.

5. An optical connector according to claim 1, wherein the biasing means is incorporated by embedding a suitably shaped spring member wholly or partly in one or both of the lid and base.

6. An optical connector according to claim 5, wherein the biasing means is incorporated by overmoulding the lid and/or the base around the relevant part(s) or whole of the spring member.

7. An optical fibre connector according to any one of claims 4 to 6, in which the spring member is substantially U-shaped.

8. An optical fibre connector according to any one of claims 4 to 6, in which the spring member is substantially planar.

9. An optical fibre connector according to any preceding claim, in which the base part and lid part are configured to form a plurality of clamping sections.

10. An optical fibre connector according to any preceding claim, in which the base part and lid part include cooperating alignment portions.