GB2176907A

GB2176907A - Optical fibre apparatus

Info

Publication number: GB2176907A
Application number: GB08615142A
Authority: GB
Inventors: Raymond Sidney Walter Assinder
Original assignee: General Electric Co PLC
Current assignee: General Electric Co PLC
Priority date: 1985-06-21
Filing date: 1986-06-20
Publication date: 1987-01-07
Also published as: GB8515779D0; GB8615142D0; GB2176907B

Abstract

In optical fibre apparatus in which an optical fibre is initially left longer than actually required to allow for recutting on re-connection, a surplus fibre storage housing (1) is provided with three or more upstanding walls (6, 7, 8) defining storage regions for fibre loops of at least two different lengths and one or more compartments to accommodate and locate components such as attenuators associated with the optical fibre path. The fibre loops are stored with one or more pre-set diameters of loop. <IMAGE>

Description

SPECIFICATION Optical fibre apparatus The present invention relates to optical fibre apparatus.

In particular the invention is concerned with apparatus in which an optical fibre forming part of an optical signal transmission path terminates in or is connected in the apparatus.

When a signal transmission is set up it is normally expected to remain viable for a number of years before wholesale replacement becomes necessary, although during this period repairs to or replacements of different parts of the system may be required from timeto time.

In the case of a line transmission system at least some of these repairs or replacements will involve disconnection and reconnection ofthetransmission line or path. While this may be quite readily carried outwith a conventional conductive transmission line, in a system utilising an optical fibre as the transmission path there is a risk of the end face of a length offibre becoming unsuitablefor reconnection due to abrasion or other damage. It is therefore preferable in an optical fibre system to re-cut the fibre to provide a fresh end face each time a connection is to be made. Such a procedure reduces the length of the fibre each time by a few centimetres.

Thus when an optical fibre transmission line is installed it is desirable to leave the line longer than the point-to-point distance requires for subsequent re-cutting at each point at which disconnection and reconnection may be required. For example each fibre may be made upto one metre longer two allow for, say, twenty or thirty reconnections. The extra length of fibre has to be protected from accidental damage, and from being coiled with too small a radius of curvature.

According to the present invention in optical fibre apparatus in which an optical fibre forming an optical signal transmission path terminating in or connected in said apparatus is initially ieft longer than is required to effect the initial termination or connection ofthetransmission path in orderto allowfor re-cutting ofthe end-face of the fibre to be carried out on re-terminating or re-connecting the fibre in said apparatus during the lifetime of the apparatus, 3 housing forthe surplus length ofthe optical fibre comprises a substantially planar base member and at leastthree upstanding wall members secured to or formed integrally with said base member, said wall members defining an outer boundary and at leasttwo inner boundaries between which outer and inner boundaries the surplus length of said optical fibre is retained as a loop having a radius of curvature of at least a predetermined minimum value.

Preferably said outer boundary and said two inner boundaries, with said base member, define storage regions in which said surplus length offibre may be retained selectively in loops of at least two different lengths. One or more ofthe upstanding wall members may be provided with one or more apertures for entry and/or exit of the optical fibre. The housing may be provided with a detachable lid such that the surplus length of said optical fibre may be substantially competely enclosed.

Optical fibre apparatus in accordance with the present invention will now be described with reference to the accompanying drawings, of which: of Figure 1 shows a plan view of a part of the apparatus, Figure2 shows a sectional view on the line Il-Il in Figure 1, Figure3 shows a plan view of another part ofthe apparatus, and Figure 4shows a sectional view on the line IV-IV in Figure 3.

Referring to the drawings the apparatus comprises a two-part protective housing for an optical fibre, comprising a tray or base 1 shown in Figures 1 and 2 and a cover or lid 2 shown in Figures 3 and 4.

Referring to Figures 1 and 2, the base 1 comprises a substantially planar member3 34.8 cms long, 1 lcms wide and 0.2cm thick having generally semicircular ends, with circular apertures 4of diameter 6.6 cms adjacent each end and a centrally disposed 12.4 cms by 5.8cms rectangular aperture 5. Around the edges of the apertures 4 and 5 and around the outer edge of the member3there are provided up-standing wall members 6,7 and 8 respectively, these wall members being, say, 0.2cm thick and extending perpendicularly to the planar member3 to a height of, say, 0.7cm from the planar member 3.Additional upstanding wall members 9,10 and 1 of substantially the same height and thickness as the wall members 7 and 8 are provided between the wall members 7 and 8, the additional wall members 9 and 10, over the major part of their lengths, extending generally parallel to the wall members 7 and 8.

Thewall members 6, 8,9 and 10 define what may be described as a race-track pattern of passageways comprising two parallel sections 12 and 13 on either side ofthe rectangular aperture 5 and a generally semicircular section 14 around either end. The wall members 11,withthe the end portionsofthewall memberS, define curving passageways 15 leading from the sections 1 4to notches 16 in the wall member 7 which communicate with the aperture 5.

An optical fibre (not shown) having surplus length to be protected may enterthe housing byway of one ofthe notches 16 and be laid in one or more loops aroundawall member 6, or around wall members 6 and along one or both ofthe sections 12, and exit by way of another of the notches 16.

The passageway sections 13 are each sized to hold an optical fibre attenuator, indicated in Figure 1 in dashed outline as a long rectangular-section block 17, together with its associated connector splices (not shown).

Projections 18 from the upper edges ofthe wall members 6 and 10 overhang the passageway sections 14 and 12, serving the retain in position any optical fibres laid in those sections.

Referring now to Figures 3 and 4the cover or lid 2 comprises a substantially planar member 19 of similar dimensions to the planar member 3 ofthe base 1, again with two circular and one rectangular apertures 20 and 21 respectively. A low rim 22 is provided around the periphery of the member 19 and a similar rim 23 is provided around the aperture 21.

Around each ofthe apertures 20 a somewhat higher rim 24is provided,the radiallyouterfaceofthisrim being provided with deformable ribs 25.

When the cover 2 is fitted to the base 1 the rims 24 of the cover 2 fit within the respective wall members 6 around the apertures 4 with the ribs 25 providing a friction grip on the innerfaces ofthe wall members 6.

The rim 23 ofthe cover 2 fits within the aperture 5 in the base 1,whilethe rim 22 surrounds the upper edge ofthe wall member 8 ofthe base 1. In this waythe passageways 12, 13, 14 and 15 in the base 1 become substantially completely enclosed, with access substantially only byway ofthe notches 16 in the wall member7. The regionsofthewall member7 in which the notches 16 occur may be of thicker section and lower in heightthan the rest of the wall member 7, as illustrated in Figures 1 and 2, and may be provided with tapped holes 26 by which a clamping and/or sealing member (not shown) may be secured once the optical fibre has been laid in the passageways of the base 1.

Claims

1. Optical fibre apparatus in which an optical fibre forming an optical signal transmission path terminating in orconnected in said apparatus is initiaily left longer than is required to effect the initial termination or connection of the transmission path in orderto allowfor re-cutting ofthe end-face ofthe fibre to be carried out on re-terminating or re-connecting the fibre in said apparatus during the lifetime ofthe apparatus, wherein a housing forthe surplus length ofthe optical fibre comprises a substantially planar base member and at leastthree up-standing wall members secured to orformed integrally with said base member, said wall members defining an outer boundary and at leasttwo inner boundaries between which outer and inner boundaries the surplus length of said optical fibre is retained as a loop having a radius of curvature of at least a predetermined minimum value.

2. Optical fibre apparatus in accordance with Claim 1 wherein said outer boundary and said two inner boundaries, with said base member, define storage regions in which said surplus length offibre may be retained selectively in loops of at least two different lengths.

3. Optical fibre apparatus in accordancewith Claim 1 or Claim 2 wherein one or more ofthe upstanding wail members is or are provided with one or more apertures for entry and/or exit ofthe optical fibre.

4. Optical fibre apparatus in accordance with Claim 1, Claim 2 or claim 3 wherein the housing is provided with a detachable lid such that the surplus length of said optical fibre may be substantially completely enclosed.

5. Optical fibre apparatus in accordance with any preceding claim wherein said upstanding wall members define one or more enclosures for locating one or more discrete components associated with said length of optical fibre.

6. Optical fibre apparatus substantially as hereinbefore described with reference to the accompanying drawings.