Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND OF THE INVENTION
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This invention relates to optical fiber connectors
and splices and, in particular, to connectors and splices
in which optical fibers are held with their cores in aligned
butting relationship.
In order to achieve -the efficient transfer of light
from the end of one optical fiber into the end of another
butted against the first, it is necessary to bring the fiber
cores into substantial alignment. This may be effected by
providing the two fiber ends with reference surfaces whose
position relative to the respective fiber cores is accurately
known. Alignment of the cores is then effected by bringing
-these reference surfaces into appropriate alignment.
This invention is concerned with the use of
cylindrical reference surfaces centered on the fibe~ cores.
The reference surface that is used may be the surface of the
fiber cladding or it may be the surface of a ferrule-type ;~
termination secured to the fiber in the region of its end.
Copending Canadian application of R. J. ~odges,
Serial No. 265,557, filed November 12, 1976, assigned to
the assignee of the present application, describes a per-
manent or demountable butt joint between the ends of a
pair of optical fibers which, in the regions of their ends
to be butt jointed, are provided with cylindrical reference
surfaces of equal diameter each of which is coaxial with
its associated fiber core. The fibers are held butted
together in alignment by a close wound helix of strip
material engaged around and gripping the two reference
surfaces.
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R. E. Epwo~t~-J. S. Leach
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SUI~MARY OF THE INVENTION
According to a principal aspect of the present invention,
there is provided an optical fiber connector for butt coupling
terminated or unterminated optical fibers. The connector
comprises a plurality of spiral springs each having a loop for
receiving a pair of fibers to be coupled and at least one ;
spring mounting means. The spiral springs are secured by the
mountlng means. The mounting means and the springs are so
arranged that movement of the mounting means in different
directions relative to the spiral springs opens or closes said
loops of the spiral springs, depending upon the direction of
movement, so as to release or secure a pair of optical fibers
placed end-to-end in said loops.
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BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 shows a spiral spring connector element
according to the invention;
Fig. 2 shows the spring of Fig. 1 coupling a
pair of optical fiber ferrules;
Figs. 3a and 3b schematically show two forms of
closed loop spring connector elements;
Fig. 4 is a cross-section of a multiway optical
connector according to the invention;
Fig. 5 and 6 are cross-sections of further types
of multiway connectors; and
Fig. 7 is a cross-section of a linear multiway
optical connector.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to Fig. 1, the coupling element 10
includes a strip 11 of spring material which may be formed
from phosphor bronæe or berylium copper. One end 12 of
the strip 11 has a cut-out 13 through which a tongue 14
at the other end of the strip 12 is threaded when the strip
is rolled, e.g. around a mandrel. As shown in Fig. 2, the
loop 15 formed by the coupling element 10 receives a pair
of optical fiber carrying ferrules 21 and 22 in end butting
relationship. Tension may then be applied to the tongue 14
and end 12 of the spring strip to close the loop securely
onto the ferrules 21 and 22 so as to hold them in axial
alignment. In some applications the spring loop 15 may
be pre-set with a diameter smaller than that of the ferrules,
the spring then being opened out to receive the ferrules.
On release the spring tension closes the loop to grip the
pair of ferrules.
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Alternative types of spring coupling elements lOa
and lOb are shown in Fig. 3a and 3b, respectively, and are
formed ~rom the spring of Fig. 1 by welding the end 12 and
tongue 14 together to ~orm a closed loop 16.
Fig. 4 shows the coupling element 10 of Fig. 1 ~`~
applied to a multiway optical fiber connector 40. The
spring coupling elements 10 are arranged with their ends ~ ;
12 and 14 secursd to the teeth 41 and 42 of relatively
rotatable members 43 and 44, respectively. Relative rota-
tion of the members 43 and 44 closes the springs to clamp -
ferrules inserted therein, or opens the springs to release
the ferrules.
Fig. 5 shows a further type of connector 50
employing an array of spring members 10 with their ends 12
and 14 welded together so as to form a circle 51. The
arrangement is inserted into a taper collet 52. The spring
loops 15 are set so that, when relaxed, they grip pairs of
ferrules inserted therein. Forcing the circle 51 into the
taper collet 52 reduces the circle diameter and opens out -
the spring loops so as to release the ferrules.
Fig. 6 shows a modification 60 of the connector of
Fig. 5 in which a circle 51 of spring loop members 10 is ~;
fitted over a ring of chuck jaws 61. Insertion of a taper
pin 62 into the center of the chuck jaws forces the jaws
apart thus expanding the circle 51 and closing the spring
loops 15.
Fig. 7 shows a linear multiway connector 70.
Spring loop members lOà or lOb of the type of Fig. 3a or
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Fig. 3b are mounted between a pair of paralle~, flat plate
members 72 and 73. Pressure on the plate members opens
the ferrule receiving loops 15.
Although the coupling arrangements described
herein are primarily intended for use with ferrule
terminated fibers, in some applications the spring loops
15 may be made sufficiently small to receive the bared fiber
ends. It should also be understood that, although the
coupled fibers are described as being in butting relation-
ship, a very small gap is, in fact, provided between thefibers to prevent mutual abrasion and damage of the fiber
ends. This gap is too small to significantly affect the
transmission qualities of the coupling but avoids damage
to the fiber ends caused by abrasion
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