GB2058396A

GB2058396A - Terminating Optic Fibers

Info

Publication number: GB2058396A
Application number: GB8027946A
Authority: GB
Original assignee: Bunker Ramo Corp
Current assignee: Bunker Ramo Corp
Priority date: 1979-09-04
Filing date: 1980-08-29
Publication date: 1981-04-08
Also published as: JPS5659215A

Abstract

The present invention is directed to an apparatus for termination of at least one cable and, more particularly, for use in distributive couplers for optical fibers in a fashion providing stress relief. While prior art optical fiber connectors are available for coupling individual optical fibers together, there is a need for distributive couplers and termination apparatus for distributing light among fiber optical transmission lines so that fiber optic transmission lines so that one or more optical fibers and a set of optical fibers without excessive loss of light carried by the optical fibers. The disclosed termination device includes a funnel member providing stress relief and the distributive members include a termination device in optical communication with an optical mixer for directing light from one or more optical fibers to a set of optical fibers with substantial uniform illumination thereof.

Description

SPECIFICATION Stress Relief for Termination Apparatus Technical Field This invention relates to an apparatus for termination of at least one cable and, more particularly to an apparatus of the type described for use with optical fibers.

Background of the Prior Art In recent years, fiber optic transmission lines made up of one or more optically conductive fibers arranged to form a flexible cable for conveying light from one location to another have come into increasing use. The Applications have varied although one particularly significant application has been conveying data from one location to another by modulating a light source with data to be transmitted at one end of the cable and recovering the data at the other end of the cable by a photosensitive detector. Since the data is conveyed by a medium not subject to ratio frequency interference or detection, fiber optic transmission lines are particularly well adapted for applications requiring a high degree of security like those found in the data processing field.

With the increasing use of fiber optic transmission lines, the need developed for connectors capable of joining segments of cables with minimum detriment to the optical transmission path. It has been found that precise axial angular and lateral alignment between a pair of fiber optic cables can be achieved by terminating the optical fibers of the cables in connector pin assemblies in such a way as to provide concentric alignment with respect to the outer dimensions of the connector pins. Once a pair of connector pins are cencentrically and accurately aligned, the ultimate result is that the optical fibers will likewise be axially, angularly and laterally aligned for efficient light transfer.

While the connector art is still developing, connector pin assemblies are available today for terminating the optical fibers of the cables so that they are concentrically and accurately aligned with accepted tolerances. More recently, there has been a growing interest in, and recognition of the need for, developing suitable distributive couplers and termination apparatus for distributing light among fiber optic transmission lines so that one or two way communication is possible from any one or more optical fibers of a set of optical fibers to all of the optical fibers of the same or a different set of optical fibers. This interest has been spawned primarily by the need to distribute an optical signal to a plurality of locations.More particularly, distributive couplers and termination apparatus have been sought which operate in the manner described while producing substantially uniform illumination of an entire set of optical fibers utilizing the light transmitted through any one or more optical fibers without excessive loss of light or excessive distortion of light signal pulses. Additionally, termination apparatus has been needed, generally, for termination of at least one cable of any type and, more particularly, for termination of at least one optical fiber, preferably, for termination of a plurality of optical fibers in a fashion providing-stress relief for the cable, optical fiber, or optical fibers.

Of course, the distributive coupler is one of many potential applications where the interconnection of many interactive terminals is required in a fiber optic communications system.

In such applications, it is necessary to terminate a given number of optical fibers and, for many applications, the geometric configuration of the termination may not be circular. Prior termination apparatus has not successfully solved the problem of terminating optical fibers particularly in non-circular configurations.

Summary of the Invention Accordingly, the present invention is directed to an apparatus for termination of at least one cable in a broad respect. The apparatus includes a terminating member having an opening extending therethrough. The terminating member has a forward end and a rearward end. The cable extends into the opening in the terminating member from the rearward end. The apparatus further includes a funnnel means associated with the rearward end of the terminating member. The funnel means communicates with the opening in the terminating member such that the cable extends through the funnel means. The funnel means provides stress relief for the cable. With these features of construction, the apparatus is well suited for terminating at least one optical fiber in various applications such as distributive couplers.

In one embodiment of the invention, the funnel means communicates with the opening in the terminating member through a neck of smaller diameter than the diameter of the funnel means rearwardly of the neck. The terminating member preferably includes a neck receiving bore communicating with the opening from the rearward end of the terminating member. The neck of the funnel means is adapted to fit within the neck receiving bore so as to be integral with the terminating member and preferably is integrally secured within the neck receiving bore by means of epoxy. Additionally, the funnel means includes an outwardly diverging conical portion rearwardly of the neck which is preferably filled with epoxy to provide stress relief for the optical fiber.

Additional features of this embodiment of the invention include the terminating member being formed of two identical blocks. The blocks preferably each include a non-planar surface defined by two parallel surface portions. The parallel surface portions of each of the blocks are joined by a non-orthogonal surface portion. The opening in the terminating member is defined by suitable juxtaposition of the parallel surface portions of each of the blocks. With this arrangement, the opening in the terminating member is non-circular in shape.

In another embodiment of the invention, the apparatus is well suited for non-circular termination of a plurality of optical fibers. It is characterized by a terminating member having a non-circular opening extending therethrough and stress relief means associated with the rearward end of the terminating member communicating with the opening in the terminating member with the optical fibers extending through the stress relief means. With these features of construction, the apparatus is highly effective for applications in which the geometric configuration of termination of optical fibers is non-circular.

Additional details of the embodiment for noncircular termination include the non-circular opening in the terminating member being polygon such as a parallelogram. The optical fibers preferably are disposed within the non-circular opening in the terminating member in two rows such that the optical fibers in one row are offset relative to the optical fibers in the other row. The stress relief means suitably includes a funnel associated with the rearward end of the terminating member which communicates with the opening of the terminating member such that the optical fibers extend through the funnel. The optical fibers preferably each include a protective jacket rearwardly of the terminating member.

With these features of construction, the funnel is preferably at least partially filled with epoxy rearwardly of theterminating member to provide stress relief for the optical fibers.

In a particular application of the invention, a distributive coupler for use with at least one set of optical fibers is provided. The coupler includes an optical mixer for directing light transmitted through any one or more of the optical fibers onto an entire set of optical fibers such that the entire set of optical fibers is uniformly illuminated. The coupler further includes a terminating member having a non-circular opening extending therethrough and having a forward end in optical communication with the optical mixer and a rearward end where the entire set of optical fibers extends into the opening in the terminating member from the rearward end.The coupler further includes funnel means associated with the rearward end of the terminating member which communicates with the non-circular opening in the terminating member such that the entire set of optical fibers extends through the funnel means. With these features of construction, a distributive coupler includes the inventive funnel means which provides stress relief for the entire set of optical fibers.

Other features of the distributive coupler may include the optical mixer being a rectangular waveguide block. The non-circular opening in the terminating member may again be a polygon such as a parallelogram. The funnel means preferably communicates with the opening in the terminating member through a neck and the terminating member includes a neck-receiving bore in the rearward end thereof which communicates with the opening in the terminating member. The funnel means further includes an outwardly diverging conical portion rearwardly of the neck with the funnel means being at least partially filled with epoxy to provide stress relief for the entire set of optical fibers. The terminating member is preferably formed of two identical blocks each including a non-planar surface defined by two parallel surface portions.

The parallel surface portions of each of the blocks are juxtapositionable to define the opening in the terminating member. Moreover, the parallel surface portions of each of the blocks are joined by a non-orthogonal surface portion and the entire set of optical fibers is disposed within the opening in the terminating member in two rows offset relative to one another.

In a more detailed embodiment of the invention, the distributive coupler includes a coupler chassis having at least one fiber optic connector communicating through a wall thereof.

It further includes an environmentally sealed housing disposed within the chassis. The optical mixer and the terminating member of the coupler are both disposed within the housing. It further includes funnel means disposed within the housing. Moreover, the housing has an opening therein for the entire set of optical fibers, the entire set of optical fibers extending from the terminating member through the opening in the housing to the fiber optic connector, the opening in the housing being environmentally sealed.

Additional details of the more specific embodiment of distributive coupler include suitability for use with two sets of optical fibers.

The coupler then includes a second terminating member and a second funnel means associated with the second terminating member. The second terminating member is disposed within the housing and has an opening extending therethrough. The second terminating member also has a forward end in optical communication with the optical mixer opposite the first terminating member and further has a rearward end. One of the sets of optical fibers extends into the opening in each of the terminating members from the rearward end thereof. The second funnel means is disposed within the housing in association with the rearward end of the second terminating member. The second funnel means also communicates with the opening in the second terminating member such that one of the sets of optical fibers extends through each of the funnel means. The distributive coupler advantageously utilizes the funnnel means to provide stress relief for both of the sets of optical fibers. Moreover, the housing has a pair of openings therein for the sets of optical fibers, one of the sets of optical fibers extending from each of the terminating members through one of the openings in the housing to the fiber optic connector, the openings in the housing being environmentally sealed.

The present invention is therefore directed to an apparatus for termination of a cable. It is more specifically an object of the present invention to provide such an apparatus suitable for terminating at least one optical fiber and, more particularly, suitable for non-circular termination of a plurality of fibers wherein the invention is particularly adapted for use with distributive couplers. Other objects and advantages of the present invention will be appreciated from a consideration of the details of construction set forth in the accompanying specification, claims, and drawing.

Brief Description of the Drawings The novel features of the present invention are set forth with particularity in the appended claims.

The invention, together with the further objects and advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying drawings. In the drawings, like reference numerals identify like elements in the several figures, in which: Figure 1 is a schematic illustration of an optical communication system with reflective star coupler; Figure 2 is a schematic illustration of an optical communication system with a transmissive star coupler; Figure 3 is an end view illustrating an arrangement of optical fibers for utilization with a rectangular lightguide; Figure 4 is a perspective view of a rectangular lightguide; Figure 5 is a perspective view of an optical fiber-rectangular lightguide assembly; Figure 6 is a top view of a transmissive star coupler with a housing portion removed in accordance with the present invention;; Figure 7 is a top view of a transmissive star coupler similar to Figure 6 illustrating optical fiber leads extending from the housing; Figure 8 is a schematic illustration of a sixteen channel single fiber transmissive start coupler; Figure 9 is a cross-sectional view of a portion of a distributive coupler in accordance with the present invention; Figure 10 is a cross-sectional view of a terminating member taken on the line 1 0-10 of Figure 9; Figure 11 is an enlarged cross-sectional view of a terminating member taken on the line 1 - 11 of Figure 9; Figure 12 is a schematic illustration of an optical fiber.

Detailed Description of the Invention Data links which employ optical fibers are being considered for many applications. In some applications, the need will exist for data links where many terminals are inter-connected. The distributive (star) coupler is a device which interconnects many terminals in a communication systems. In such systems, the design commonly requires the signals from each source to reach each detector. Referring to Figures 1 and 2, the distributive coupler systems illustrated utilize, respectively, reflective and transmissive star couplers.

More particularly, referring to Figure 1, a reflective start coupler 20 is schematically illustrated. It includes a plurality of terminals 22.

The reflective star coupler 20 communicates through the terminals 22 with respective optical fibers 24. It receives signals from any one or more of the sources 26. Moreover, the reflective star coupler 20 returns the signals in substantially uniform fashion to each of the detectors 28.

Referring to Figure 2, a transmissive star coupler 30 is schematically illustrated. It includes a plurality of terminals 32 on the "source" side of the system and a plurality of terminals 34 on the detector side of the system. The transmissive star coupler 30 is in optical communication through the terminals 32 with optical fibers 36 and through the terminals 34 with optical fibers 38. It receives signals from any one or more of the sources 40. Moreover, the transmissive star coupler 30 directs the signal to each of the detectors 42 in substantially uniform fashion.

Generally, a component common to all star couplers is an optical mixer for mixing and distributing light The optical mixer may be a cylindrically shaped rod of transparent material, a plurality of optical fibers which have been softened, pulled and joined with a clear optical adhesive, a combination of dioptric components of various types, or a rectangular waveguide. It has been found that an advantage of a rectangular waveguide is the uniformity of the light at the output end and another advantage of the rectangular geometry is a configuration or arrangement permitting optical fibers to be arranged in two rows. The two rows of optical fibers can be offset relative to one another by a half diameter. With this approach, the configuration or arrangement of optical fibers has a low packing fraction loss.

Referring to Figure 3, two rows of optical fibers 44 having cladding 46 are illustrated. The two tows are offset by a half diameter and the low packing fraction loss is apparent. The rectangular waveguide 48 with cladding 50 is illustrated in Figure 4. The two rows of optical fibers 44 can be placed in optical communication with an end 52 of the rectangular waveguide 48. Similarly, two additonal rows of optical fibers may be placed in optical communication with the opposite end 54 of the rectangular waveguide 48 as illustrated in Figure 5.

Referring again to Figures 3 and 5, the two rows or layers of optical fibers 44 have been combined such that one row or layer is displaced by one half fiber diameter relative to the other row or layer. This forms a parallelogram type array. The two rows or layers each include eight optical fibers in the illustration. This has been chosen merely by way of example. As will be appreciated, the precise number of optical fibers in each row will depend upon design requirements.

In the illustrations given and with reference now to Figure 6, the reference numeral 56 designates generally an apparatus for termination of at least one cable. The apparatus 56 includes a terminating member 58 (as shown in Figure 9) having an opening 60 extending therethrough.

The terminating member 58 has a forward end 62 and a rearward end 64. The cable extends into the opening 60 in the terminating member 58 from the rearward end 64. The apparatus 56 further includes funnel means 66 associated with rearward end 64 of the terminating member 58.

The funnel means 66 communicates with the opening 60 in terminating member 58 such that the cable extends through the funnel means 66.

The funnel means 66 provides stress relief for the cable. With these features of construction, the apparatus 56 is well suited for termination of at least one optical fiber 44.

Referring to Figure 10, it will be appreciated that the opening 60 in the terminating member 58 can be non-circular. The terminating member 58 can also be formed of two identical blocks 58' and 58". It will be appreciated that the optical fibers 44 are then disposed between the two identical blocks 58' and 58" in the opening 60 defined thereby. The optical fibers 44 may be secured within the opening 60 by means of epoxy. By utilizing epoxy, the optical fibers 44 can be secured in the opening 60 in a fashion preventing any relative movement.

Considering the funnel means 66 illustrated in figure 9, it includes a neck portion 70 and a funnel portion 72. The neck portion 70 communicates with the opening 60 in the terminating member 58 and is of smaller diameter than the diameter of the funnel portion 72 rearwardly of the neck 70.

By filling at least the funnel portion 72 of the funnel means 66 with epoxy (as at 74), the optical fibers 44 are provided with highly effective stress relief.

Referring again to Figure 10, the blocks 58' and 58" each include a non-planar surface defined by two parallel surface portions 76 and 78. The parallel surface portions 76 and 78 of each of the blocks 58' and 58" are juxtapositionable to define the opening 60 in the terminating member 58. The parallel surface portions 76 and 78 of each of the blocks 58' and 58" are also joined by non-orthogonal surface portion 80. By constructing the terminating member 58 in this fashion, the opening 60 in the termination member 58 is non-circular in shape as previously described.

As shown in Figure 9, the optical fibers 44 preferably extend to the forward end 62 of the terminating member 58. It will be appreciated by those skilled in the art that the optical fibers 44 may be polished to an optical finish at the forward end or front face 62 of the terminating member 58. The rearward end or rear face 64 of the terminating member 58 includes a neck receiving bore 82 therein which is preferably generally cylindrical in shape. The neck receiving bore 82 communicates with the opening 60 in the terminating member 58 and the neck 70 is adapted to fit within the neck receiving bore 82 so as to be integral with the terminating member 58. The neck 70 is preferably integrally secured within the neck receiving bore 82 with epoxy (as at 84).It will be appreciated that the funnel portion 72 is an outwardly diverging conical portion of the funnel means 66 rearwardly of the neck 70. As previously described, the funnel means 66 rearwardly of the neck 70 is suitably filled with epoxy to provide stress relief for the optical fibers 44.

As will be appreciated from a consideration of Figures 9, 10 and 11, the apparatus 56 is particularly well suited for non-circular termination of a plurality of optical fibers 44. It has been found that non-circular termination presents peculiar problems requiring stress relief means (such as 66) associated with the rearward end 64 of the terminating member 58. The preferred form of stress relief means is the unique funnel means 66 cooperable with terminating member 58 in the fashion described. It has been found that a funnel having circular cross-section at every point along its length is highly effective for providing stress relief for optical fibers terminated in a non-circular opening in a terminating member.By referring to Figures 9 and 11, it will be appreciated how the circular neck 70 disposed within the circular opening 82 leads to and communicates with the non-circular opening 60 in the terminating member 58.

Moreover, the non-circular opening 60 in the terminating member 58 is preferably polygonal. It has been found particularly advantageous for the polygonal opening 60 to be parallelogram. This basically follows from the fact that a parallelogram configuration or arrangement of optical fibers (as shown in Figure 3) results in a low packing fraction loss. It will also be appreciated that the parallelogram arrangement lines up well with a rectangular waveguide. As a result, a parallelogram opening 60 in the terminating member 58 is particularly well suited for use with a rectangular waveguide 48 in a distributive coupler (such as 86).

Referring to the distributive coupler 86 illustrated in Figure 7, the principles of the coupler are adapted for use with at least one set 88 of optical fibers (such as 44). The distributive coupler 86 includes an optical mixer or waveguide (such as 48) for directing light transmitted through any one or more of the optical fibers (such as 44) onto an entire set of optical fibers 88 such that the entire set of optical fibers is uniformly illuminated. The distributive coupler 86 also includes a terminating member (such as 58) having a non-circular opening (such as 60) extending therethrough. The terminating member 58 has a forward end (such as 62) in optical communication with the optical mixer or waveguide 48 and a rearward end (such as 64).

The entire set of optical fibers 88 extend into the opening 60 in the terminating member 58 from the rearward end 64 thereof. The distributive coupler 58 further includes funnel means (such as 66) associated with the rearward end 64 of the terminating member 58. The funnel means 66 communicates with the non-circular opening 60 in the terminating member 58 such that the entire set of optical fibers 88 extends through the funnel means 66. The funnel means 66 provides stress relief for the entire set of optical fibers 88.

Accordingly, the priciples of the invention are broadly applicable to distributive couplers of a wide variety.

More particularly, the principles of the invention are applicable to either reflective mode couplers (such as 20 illustrated in Figure 1 or transmissive mode couplers (such as 30 illustrated in Figure 2). It will be appreciated that a transmissive mode coupler comprises the distributive coupler 86 illustrated in Figures 6, 7 and 8. The principal difference between a reflective mode coupler and a transmissive mode coupler is, in the latter case, the elimination of one of the two sets of terminating members 58, funnel means 66, and entire sets of optical fibers 88. It will be appreciated that the reflective mode coupler will also differ in that the optical mixer or waveguide 48 will have a reflective surface at the end thereof remote from the remaining terminating member 58.Otherewise, the principal of the invention as it applies to the remaining terminating member 58, funnel means 66, and entire set of optical fibers 88 will remain the same.

In either a reflective mode coupler or a transmissive mode coupler, the optical mixer or waveguide 48 is still suitably a rectangular waveguide block. The non-circular opening 60 in the terminating member 58 is still polygonal and preferably a parallelogram. The funnel means 66 still communicates with the opening 60 in the terminating member 58 through a neck 70. The terminating member 58 still includes a neck receiving bore 82 in the rearward end 64 thereof.

Additionally, the neck receiving bore 82 still communicates with the opening 60 in the terminating member 58.

Other details of construction of the distributive coupler 86 (whether reflective mode coupler or transmissive mode coupler illustrated) include the funnel means 66 still having an outwardly diverging conical portion 72 rearwardly of the neck 70. The funnel means 66 is still at least particaliy filled with epoxy 74 to provide stress relief for the entire set of optical fibers 88. The terminating member 58 is still formed of two identical blocks 58' and 58" each including a non-planar surface defined by two parallel surface portions 76 and 78. The parallel surface portions 76 and 78 of each of the blocks 58' and 58" are still juxtapositionable to define the opening 60 in the terminating member 58. The parallel surface portions 76 and 78 of each of the blocks 58' and 58" are still joined by a non-orthogonal surface portion 80.Still additionally, the entire set of optical fibers 88 is still disposed within the opening 60 in the terminating member 58 in two rows offset relative to one another.

In a more specific embodiment of distributive coupler, the coupler 86 includes a coupler chassis 90 having at least one fiber optic connector 92 communicating through a wall 94 thereof (as shown in Figure 8). It also has an environmentally sealed housing 96 disposed within the chassis 90. The optical mixer or waveguide 48, the terminating member 58 and the funnel means 66 are disposed within the housing 96. It will be seen from Figure 6 that the housing 96 has an opening 98 therein for the entire set of optical fibers 88.

Moreover, the entire set of optical fibers 88 extend from the terminating member 58 through the opening 98 in the housing 96 to the fiber optic connector or connectors 92 with the opening 98 in the housing 96 being environmentally sealed.

As will be appreciated, the distributive coupler 86 illustrated in Figures 6, 7 and 8 is adapted for use with two sets of optical fibers 88 in a transmissive mode coupler. The coupler 86 then includes a second terminating member 58 and a second funnel means 66 associated with the second terminating member 58. The second terminating member 58 is similarly disposed within the housing 96 and similarly has an opening 60 extending therethrough. The second terminating member 58 similarly has a forward end 62 in optical communication with the optical mixer or waveguide 48 and further has a rearward end 64. The opening 60 in each of the terminating members 58 similarly has one of the sets of optical fibers 88 extending into the rearward end thereon.The second funnel means 66 is similarly disposed within the housing 96 in association with the rearward end 64 of the second terminating member 58. The second funnel means 66 similarly communicates with the opening 60 in the second terminating member 58 such that one of the sets of optical fibers 88 extends through each of the funnel means 66.

The funnel means 66 similarly provides stress relief for both of the sets of optical fibers 88.

Moreover, the housing 96 for a transmissive coupler 86 has a pair of openings 98 therein for the sets of optical fibers 88, one of the sets of optical fibers 88 extending from each of the terminating members 58 through one of the openings 98 in the housing 96 to at least one fiber optic connector 92, the openings 98 in the housing 96 being environmentally sealed.

Referring to Figure 12, a typical fiber optic cable 100 is illustrated. The fiber optic cable 100 includes an outer jacket 102, a strength member 104, and inner jacket 106, a fiber with buffer 108, and a fiber without buffer 110. As will be appreciated, the fiber optic cable 100 is merely illustrative of fiber optic cables capable of advantageously utilizing the invention.

Referring to Figure 9, the entire set of optical fibers 88 can generally be comprised of a plurality of fiber optic cables (such as 100 illustrated in Figure 12). The optical fibers 44 of Figure 9 will then correspond directly to the fiber with buffer 108. It will also be appreciated that at least the inner jacket portions 106 of the fiber optic cables 100 extend into the funnel portion 72 of the funnel means 66 such that the inner jack portions 106 end at or about the end of a generally cylindrical portion 112 of the funnel means 66 rearwardly of the outwardly diverging conical portion 72. The outer jacket portions 102 of the fiber optic cables 100 end rearwardly of the generally cylindrical portion 112 of the funnel means 66.As shown in Figure 9, the epoxy 74 can be applied within the generally cylindrical portion 112 of the funnel means 66 and rearwardly of the generally cylindrical portion 112 of the funnel means 66 to cooperate with the innerjacket portions 106 and the outer jacket portions 102 of the fiber optic cables 100.

Other details of construction can be appreciated from consideration of Figure 9. It will be noted, for instance that the entrance to the opening 60 nearest the rearward end 64 of the terminating member 58 is machined so as to reduce the possibility of sharp edges abrading the optical fibers 44. It will also be noted, for instance, that the generally cylindrical portion 112 of the funnel means 66 has a diameter which is sufficiently large to receive the inner jacket portions 106 of all of the fiber optic cables 100. It will further be noted, for instance, that the generally cylindrical portion 112 of the funnel means 66 is sufficiently elongated so that the fiber optic cables 100 can be secured with epoxy.

Moreover, the design features of the present invention provide stress for the cables, whether fiber optic, electrical, coaxial, or otherwise, in a highly effective fashion.

Referring again to Figures 6 and 7, it will be apprecaiated that the distributive coupler 86 is comprised of a housing having a base portion 114 and a top portion 11 6. The portion 114 is further characterized by two end compartments 11 8 and a center compartment 120. The center compartment 120 houses the terminating members 58 and the optical mixer or waveguide 48. These compartments are secured in place within the center compartment 120 by epoxy 122. The funnel means 66 extend from the end compartments or sections 11 8 into the center compartment or portion 120 through openings 124. The sets of optical fibers 88 extend outwardly from the funnel means 66 through the openings 98.Additionally, a protective boot 126 cooperates with each of the funnel means 66, extends rearwardly from each of the funnel means 66 through the openings 98, covers each of the entire sets of optical fibers 88, and is epoxied (as at 128) into each of the end compartments or segments 11 8 of the base portion 114 of the distributive coupler 86.

As will be appreciated, the protective boots 126 provide bend relief rearwardly of the funnel means 66, and particularly at the openings 98, for the entire sets of optical fibers 88. It will also be appreciated that the top 11 6 of the distributive coupler 86 can be secured to the base 114 thereof to protectively enclose all of the components of the distributive coupler 86.

Moreover, it will be appreciated by those skilled in the art that the housing can be environmentally sealed using suitable techniques in the art.

With the present invention, it is possible to provide stress relief for termination apparatus for any cable structure. This is accomplished in an entirely unique fashion utilizing, in a preferred embodiment, funnel means which is particularly well suited for non-circular terminations although the applications are certainly not limited to such.

The funnel means is well adapted for termination of optical fibers in a distributive coupler but, in a broader sense, is well adapted for use in any termination apparatus. This provides maximum versatility in a structure which is simple but highly effective. Accordingly, the present invention represents a significant advancement in the art of stress relief for termination apparatus.

While in the foregoing specification a detailed description of the invention concepts has been set forth for purposes of illustration, the details herein given may be varied by those skilled in the art without departing from the spirit and scope of the invention set for and defined by the appended

Claims

claims. Claims

1. An apparatus for termination of at least one cable, comprising: a terminating member having an opening extending therethrough, said terminating member having a forward end and a rearward end, said cable extending into said opening in said terminating member from said rearward end; and funnel means associated with said rearward end of said terminating member, said funnel means communicating with said opening in said terminating member such that said cable extends through said funnel means, said funnel means providing stress relief means for said cable.

2. The apparatus as claimed in Claim 1 in which said funnel means includes a neck portion and a funnel portion.

3. The apparatus as claimed in Claim 2 in which said funnel means is at least partially filled with epoxy rearwardly of said terminating member.

4. The apparatus as claimed in Claim 3 in which said funnel portion of said funnel means is filled with epoxy.

5. The apparatus as claimed in Claim 2, wherein said cable is at least one optical fiber and said funnel portion communicates with said opening through said neck, said neck portion having a smaller diameter than the diameter of said funnel portion.

6. The apparatus as claimed in Claim 5 in which said terminating member is formed of two identical blocks.

7. The apparatus as claimed in Claim 6 in which said blocks each include a non-planar surface defined by two parallel surface portions.

8. The apparatus as claimed in Claim 7 in which said parallel surface portions of each of said blocks are juxtapositionable to define said opening in said terminating member.

9. The apparatus as claimed in Claim 8 in which said parallel surface portions of each of said blocks are joined by a non-orthogonal surface portion.

10. The apparatus as claimed in Claim 5 in which said opening in said terminating member is non-circular in shape.

11. The apparatus as claimed in Claim 5 in which said optical fiber extends to said forward end of said terminating member.

12. The apparatus as claimed in Claim 5 in which said terminating member includes a neck receiving bore in the rearward end thereof.

13. The apparatus as claimed in Claim 12 in which said neck receiving bore communicates with said opening in said terminating member.

14. The apparatus as claimed in Claim 13 in which said funnel portion includes an outwardly diverging conical portion rearwardly of said neck.

15. The apparatus as claimed in Claim 14 in which said neck is adapted to fit within said neck receiving bore so as to be integral with said terminating member.

1 6. The apparatus as claimed in Claim 15 in which said neck is integrally secured within said neck receiving bore with epoxy.

17. The apparatus as claimed in Claim 10 in which said non-circular opening in said terminating member is polygonal.

18. The apparatus as claimed in Claim 17 in which said non-circular opening in said terminating member is a parallelogram.

19. The apparatus as claimed in Claim 10 in which said optical fibers are disposed within said non-circular opening in said terminating member in two rows.

20. The apparatus as claimed in Claim 19 in which said optical fibers in one row are offset relative to said optical fibers in the other row.

21. The apparatus as claimed in Claim 5 in which said optical fibers each include a protective jacket rearwardly of said terminating member.

22. A distributive coupler for use with at least one set of optical fibers, comprising: an optical mixer for directing light transmitted through any one or more of said optical fibers onto an entire set of optical fibers such that said entire set of optical fibers is essentially uniformly illuminated; and a terminating member having a non-circular opening extending there-through, said terminating member having a forward end in optical communication with said optical mixer and a rearward end, said entire set of optical fibers extending into said opening in said terminating member from said rearward end; and funnel means associated with said rearward end of said terminating member, said funnel means communicating with said non-circular opening in said terminating member such that the said entire set of optical fibers extends through said funnel means, said funnel means providing stress relief for said entire set of optical fibers.

23. The coupler as claimed in Claim 22 in which said optical mixer is a rectangular waveguide block.

24. The apparatus as claimed in Claim 22 in which said non-circular opening in said terminating member is polygonal.

25. The apparatus as claimed in Claim 22 in which said opening in said terminating member is a paralellogram.

26. The apparatus as claimed in Claim 22 in which said funnel means communicates with said opening in said terminating member through a neck.

27. The apparatus as claimed in Claim 26 in which said terminating member includes a neck receiving bore in the rearward end thereof.

28. The apparatus as claimed in Claim 27 in which said neck receiving bore communicates with said opening in said terminating member.

29. The apparatus as claimed in Claim 28 in which said funnel means further includes an outwardly diverging conical portion rearwardly of said neck.

30. The apparatus as claimed in Claim 22 in which said funnel means is at least partially filled with epoxy to provide stress relief for said entire set of optical fibers.

31. The apparatus as claimed in Claim 22 in which said terminating member is formed of two identical blocks each including a non-planar surface defined by two parallel surface portions.

32. The apparatus as claimed in Claim 31 in which said parallel surface portions af each of said blocks are juxtapositionable to define said opening in said terminating member.

33. The apparatus as claimed in Claim 32 in which said parallel surface portions of each of said blocks are joined by a non-orthogonal surface portion.

34. The apparatus as claimed in Claim 33 in which said entire set of optical fibers is disposed within said opening in said terminating member in two rows offset relative to one another.

35. The coupler as claimed in Claim 22 further including: a coupler chassis having said at least one fiber optic connector communicating through a wall thereof and an environmentally sealed housing disposed within said chassis, said optical mixer terminating member and funnel means being disposed within said housing and said housing having an opening therein for said entire set of optical fibers, said entire set of optical fibres extending from said terminating member through said opening in said housing to said fiber optic connector, said opening in said housing being environmentally sealed.

36. The coupler as claimed in Claim 35 in which said distributive coupler is adapted for use with two sets of optical fibers.

37. The coupler as claimed in Claim 36, including a second terminating member and a second funnel means associated with said second terminating member.

38. The coupler as claimed in Claim 37 in which said second terminating member is disposed within said housing and has an opening extending therethrough, said second terminating member having a forward end in optical communication with said optical mixer opposite said first terminating member and further having a rearward end, one of said sets of optical fibers extending into said opening in each of said terminating members from said rearward end thereof.

39. The coupler as claimed in Claim 38 in which said second funnel means is disposed within said housing in association with said rearward end of said second terminating member, said second funnel means communicating with said opening in said second terminating member such that one of said sets of optical fibers extends through each of said funnnel means, said funnel means providing stress relief means for both of said sets of optical fibers.

40. The coupler as claimed in Claim 39 in which said housing has a pair of openings therein for said sets of optical fibers, one of said sets of optical fibers extending from each of said terminating members through one of said openings in said housing to said fiber optic connector, said openings in said housing being environmentally sealed.