US20090103871A1 - Fiber optic furcation device including expansion chamber - Google Patents

Abstract

An optical fiber device with an optical fiber extending from a first outer jacket through a fiber receiving device from a first outer jacket to a second outer jacket. The first outer jacket is anchored to a side of a housing of the fiber receiving device and the second outer jacket is anchored to a side of the fiber receiving device. The housing defines an interior which received the optical fiber and provides space for accumulating excess length of optical fiber generated by differential thermal contraction of the jackets and the optical fiber.

Description

CROSS REFERENCE TO RELATED APPLICATION
• This application is a continuation of application Ser. No. 11/064,164, filed Feb. 23, 2005, which application is incorporated herein by reference.
FIELD
• The present invention generally relates to optical fiber cable construction and furcation module construction.
BACKGROUND
• Optical fiber cables are typically composed of a variety of linear elements which are terminated and constrained linearly with respect to each other. These elements may include the optical fiber itself, tubular sheathing materials, linear strength members, and outer layers for sealing the other elements from environmental damage from rain or other moisture. Each of these elements may have different thermal coefficients of expansion. At temperatures near the ambient temperature present when the cable is assembled and terminated, the differences in thermal expansion of the various elements is not significant enough to cause any attenuation or insertion loss to optical signals being transmitted by the cable.
• However, as these cables are exposed to temperatures more extreme with respect to the ambient temperature at the time of assembly and termination, the differing thermal expansion coefficients may become more significant. Optical fiber cables may be exposed to operating temperatures up to one hundred degrees Fahrenheit removed from the ambient temperature of assembly and termination. At these temperatures, the differing degrees of elongation or contraction among the elements of the cable may damage the fiber or may cause unacceptable amounts of attenuation or insertion loss of signals being transmitted over the cable. Improvements to known optical fiber cables to address temperature-induced stresses are desirable.
SUMMARY
• The present invention relates to an optical fiber device with an optical fiber extending from a first outer jacket through a fiber receiving device from a first outer jacket to a second outer jacket. The first outer jacket is anchored to a side of a housing of the fiber receiving device and the second outer jacket is anchored to a side of the fiber receiving device. The housing defines an interior which received the optical fiber and provides space for accumulating excess length of optical fiber generated by differential thermal contraction of the jackets and the optical fiber.
BRIEF DESCRIPTION OF THE DRAWINGS
• The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate several aspects of the present invention and together with the description, serve to explain the principles of the invention. A brief description of the drawings is as follows:
• FIG. 1 is a cross-sectional view of a prior art optical fiber cable segment.
• FIG. 2 is a cross-sectional view of the prior art optical fiber cable segment ofFIG. 1 at a reduced ambient temperature where the ends of the fiber and the cable jacket are not constrained with respect to each other.
• FIG. 3 is a cross-sectional view of the prior art optical fiber cable segment ofFIG. 1 at a reduced temperature where the ends of the fiber and the cable jacket are constrained with respect to each other.
• FIG. 4 is a perspective view of an optical fiber cable including a loop housing in accordance with the present invention.
• FIG. 5 is a top view of the optical fiber cable ofFIG. 4 with the top removed from the loop housing.
• FIG. 5A is a top view of a first alternative embodiment of an optical fiber cable in accordance with the present invention including a coupler within a loop housing with the top removed from the housing.
• FIG. 6 is a perspective view of an optical fiber cable and splitter in accordance with the present invention.
• FIG. 7 is a perspective view of a second alternative embodiment of an optical fiber cable including a loop housing and splitter mounted within the loop housing in accordance with the present invention, with the fiber and splitter within the housing shown in hidden lines.
• FIG. 8 is a side view with partial cross-section of a third alternative embodiment of an optical fiber cable with in accordance with the present invention including an intermediate portion of tubing to receive excess fiber length.
• FIG. 9 is a front perspective view of a prior art optical fiber module in accordance with the present invention.
• FIG. 10 is a top view of the prior art optical fiber module ofFIG. 9.
• FIG. 11 is a front view of the prior art optical fiber module ofFIG. 9.
• FIG. 12 is a top view of the prior art optical fiber module ofFIG. 9, with the top of the module removed to permit visibility of the interior of the module.
• FIG. 13 is a top view of a generalized layout of the optical fibers within the prior art optical module ofFIG. 9.
• FIG. 14 is a rear perspective view one of the optical fiber up-jacket mounting blocks from the front of the prior art optical module ofFIG. 9, with a single up-jacket tubing assembly mounted within one of the mounting openings for sheathing one of the plurality of fibers extending from splitter.
• FIG. 15 is a side view of the optical fiber up-jacket tubing assembly fromFIG. 13.
• FIG. 16 is an exploded view of the optical fiber up-jacket tubing assembly ofFIG. 15.
• FIG. 17 is a side view of an optical fiber up-jacket assembly for sheathing the single input fiber to the splitter.
• FIG. 18 is a rear exploded perspective view of the single input fiber extending through the front of the prior art optical module ofFIG. 9.
• FIG. 19 is a perspective view of a fiber optic device in accordance with the present invention.
• FIG. 20 is a top view of the fiber optic device ofFIG. 19.
• FIG. 21 is an end view of the fiber optic device ofFIG. 19.
• FIG. 22 is a cross-sectional view of the fiber optic device ofFIG. 19, taken along line22-22 inFIG. 21.
• FIG. 23 is a perspective view of a first alternative fiber optic device including an expansion chamber according to the present invention.
• FIG. 24 is a top view of the fiber optic device ofFIG. 23.
• FIG. 25 is an end view of the fiber optic device ofFIG. 23.
• FIG. 26 is a view of an interior of the fiber optic device ofFIG. 23, with the cover removed.
• FIG. 27 is an exploded perspective view of the fiber optic device ofFIG. 23.
• FIG. 28 is a perspective view of a second alternative embodiment of a fiber optic device with expansion chamber according to the present invention.
• FIG. 29 is a top view of the fiber optic device ofFIG. 28.
• FIG. 30 is an end view of the fiber optic device ofFIG. 28.
• FIG. 31 is a cross-sectional view of the fiber optic device ofFIG. 28, taken along line31-31 inFIG. 30.
DETAILED DESCRIPTION
• Reference will now be made in detail to the exemplary aspects of the present invention that are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
• Optical fiber cables may be installed within telecommunications networks and exposed to the extremes of outside air temperatures. These optical fiber cables are made of a variety of materials, including but not limited to the optical fiber itself, jacketing and cladding, and strength members. Each of these constituent materials may have a different thermal coefficient of expansion, meaning that the materials will expand or contract at different rates due to temperature changes. The prior art optical fiber cables inFIGS. 1 to 3 show the effect of reduced temperature on anoptical fiber cable10 including anouter jacket12 and anoptical fiber14. Fiber14 is slidably held within ahollow opening16 defined byjacket12.Jacket12 includes afirst end18 and an opposingsecond end20 andfiber14 includes corresponding first andsecond ends22 and24.
• InFIG. 1,cable10 is exposed to a first temperature such that the ends offiber14 andjacket12 are aligned with each other. Iffiber14 andjacket12 were originally the same length at the time of their assembly, this indicates that the first temperature is approximately equal to the ambient temperature at whichcable10 was assembled.Cable10 may be an optical fiber drop cable wherefiber14 is freely slidable within opening16 ofjacket14. The first ends18 and22 and the second ends20 and24 are not fixed or constrained with respect to each incable10.
• InFIG. 2,cable10 has now been exposed to a second temperature below the first temperature.Fiber14 has a thermal coefficient of expansion which is relatively smaller than a thermal coefficient of expansion ofjacket12. At the second temperature,jacket12 has contracted much more thanfiber14. Ends22 and24 offiber14 extend beyond ends18 and20, respectively, ofjacket12. Ends22 and24 offiber14 are unconstrained at ends18 and20, respectively, and are free to move beyond ends18 and20, as shown. Ends22 and24 extend beyond ends18 and20 to define anexcess length15 offiber14.
• Alternatively, one of the first or second ends offiber14 andjacket12 might be constrained with respect to each other provided the opposite ends are unconstrained andfiber14 is freely movable within opening16 ofjacket12.
• InFIG. 3,cable10 is now terminated at each of the first and second ends with anoptical fiber connector26. Such optical fiber connectors are well known in the art. To terminatecable10 atconnector26,jacket12 andfiber14 are constrained with respect to each other. Whileoptical fiber connector26 may provide some degree of movement in compression offiber14,connector26 does not permitfiber14 to extend beyondconnector26. As shown inFIG. 3,cable10 is exposed to the second, lower temperature andjacket12 has contracted to the same extent shown inFIG. 2. InFIG. 3, however, ends22 and24 offiber14 are now constrained at ends18 and20 ofjacket12 byconnectors26. Thus, the contraction ofjacket12compresses fiber14 into the same length asjacket12. Known materials suitable for makingoptical fiber12 are essentially incompressible.Excess length15 offiber14 is forced to fit within a shorter length ofjacket12 and is forced into a series ofmicrobends28 withinopening16. Thesemicrobends28 may cause excess signal loss withincable10. Whilecable10 is shown as a single fiber cable andconnectors26 are described as fiber connectors, it is anticipated that a cable including multiple optical fibers could be substituted forcable10 and a cable breakout at the end of such a multifiber cable could be substituted forconnector26 within the present invention.
• Referring now toFIGS. 4 and 5, acable30 in accordance with the present invention includes afirst jacket segment32, asecond jacket segment34,fiber14 andconnectors26 at each end. As discussed above, bothfiber14 andjackets segments32 and34 are constrained with respect to each other atconnectors26. Mounted betweenjacket segments32 and34 is afiber receiving device36. As shown, the fiber receiving device is afiber loop box36.Fiber14 extends from afirst connector26 throughjacket segment32 intobox36, forms aloop38 and then extends throughjacket segment34 to asecond connector26.
• Whencable30 is exposed to a range of temperatures andjacket segments32 and34 extend and contract in response, any excess length offiber14 is gathered withinbox36.Loop38 offiber14 is sized to fit withinbox36 offset from the inner surfaces40. This will allowloop38 to grow in size without being limited byinner surfaces40 asexcess length15 is incorporated withinloop38.Box36 should be sized to permit the formation of a loop that is greater in diameter than the minimum bend radius offiber14.
• FIG. 5A shows anoptical fiber cable80 similar tocable30, with the addition of anoptical device84 such as a coupler mounted withinbox36.Fiber14 extends throughfirst cable segment32 fromconnector26 intobox36 forming aloop38 to receive excess fiber length and is constrained atoptical device84. Withindevice84, a portion of the signal transmitted byfiber14 is tapped or split into a second fiber such as afiber82. Anextension15 offiber14 is constrained atdevice84 and extends out of box35 throughsecond jacket segment34 toconnector26.Fiber82 extends fromdevice84 out ofbox36. Bothfibers15 and82form loops38 withinbox36 to receive excess fiber length withinbox36.
• FIG. 6 shows an alternative embodiment of anoptical fiber cable46 in accordance with the present invention.Cable46 includesfiber segments32 and34 andfiber loop box36. Optical fiber14 (shown withinbox36 in hidden lines) withincable46 is a single strand of fiber carrying a plurality of optical signals simultaneously.Segment32 andfiber14 withinsegment32 are constrained at one end atconnector26. At a second end ofsegment34 ofcable46, asplitter42 is included.Fiber14 andjacket segment34 are constrained with respect to each other at one end ofsplitter42. Withinbox36,fiber14 forms aloop38 to receive any excess fiber that might be formed whenjacket segments32 and/or34 contract more thanfiber14. At an opposite end ofsplitter42 are a plurality ofoptical fibers44. Each of thesefibers44 may carry one of the plurality of optical signals from fiber33 which has been separated from the other optical signals bysplitter42. As shown, eightoptical fibers44 extend fromsplitter42. Alternatively,individual fibers44 could be combined into a single ribbon fiber extending fromsplitter42 and theindividual fibers44 broken out from the ribbon cable at a point removed fromsplitter42. (Such an arrangement is shown inFIG. 12, below.)
• FIG. 7 shows a further alternative embodiment of anoptical fiber cable48 includingfirst jacket segment32 withconnector26 at one end.Segment32 andfiber14 withinsegment32 are constrained atconnector26. Within a fiber loop box50 asplitter42 is mounted so thatfibers44 extend frombox50.Fiber14 is constrained withinbox50 atsplitter42. First jacket segment is constrained atbox50 opposite fromconnector26.Cable48 does not include asecond jacket segment34 within which fiber33 extends. Aloop38 of optical fiber withinbox50 betweenjacket segment32 andsplitter42 permits anyexcess cable length15 due to contraction ofjacket segment32 to be absorbed without creating microbends which might create undesirable signal loss. As above,fibers44 could be combined into a single ribbon cable and broken out into individual fibers at a point removed frombox50.
• FIG. 8 illustrates a still further alternative embodiment of anoptical fiber cable52 including awider portion56 of acable jacket54. Withinportion56 is defined anenlarged segment58 of opening16 through whichfiber14 extends. As described above, ends18 and20 ofjacket54 and ends22 and24 offiber14 are constrained with respect to each other, respectively. Asjacket54 contracts linearly when exposed to low ambient temperatures,excess fiber length15 is collected within acurve60 withinenlarged segment58.Segment58 is sized to allow accumulation of the anticipated amount ofexcess fiber length15 based on the overall length ofcable52 and the percentage of shrinkage calculated at the lowest ambient temperature for which cable53 is likely to be subjected. This accumulation ofexcess fiber length15 withcurve60 will avoid the problem of forcing microbending within opening16 as shown above inFIG. 3. Alternatively,wide portion56 andsegment58 could be created in one or more standard sizes and the appropriate size incorporated intocable52 depending of the length ofcable52 and a standardized lowest expected ambient temperature.
• Referring now toFIGS. 9 to 11, atelecommunications module100 is shown with an inputoptical fiber cable102 and a plurality of outputoptical fiber holders104 mounted to afront106.Module100 includes a housing with a top108, a pair of opposingsides110, a bottom112 (shown inFIG. 12, below), and aback114. The housing defines an interior116 (also shown inFIG. 12, below). As shown,module100 is an optical fiber splitter module, capable of separating an incoming optical fiber signal fromcable102 into up to thirty-two output optical fiber signals, each signal transmitted through an outputoptical fiber cable118 terminated at anoptical fiber connector119. Onecable118 is shown inFIG. 10. Each of theoptical fiber holders104 is adapted to hold up to eightoutput cables118.
• On each of thesides110 is a mountingrail120, adapted for mountingmodule100 to a telecommunications equipment rack or similar structure.Adjacent sides110,face106 includes a pair offlanges122 with one ormore fastener openings124.Flanges122 andopenings124 aid with the mounting and secure fastening ofmodule100 to such a rack or structure. Each of theholders104 includes eightopenings126, each opening126 adapted to receive one of theoutput fibers118. Onfront106 is aspace128 for receivingindicia identifying module100 or the cables extending to or frommodule100. On top108 is a space for receiving alabel130. As shown,front106 is angled with respect to back114 to aid access tofront106 orcables102 and118 and to improve the cable management of these cables extending to and frommodule100.
• FIG. 12shows module100 with top108 removed to show routing of optical fibers withininterior116.Flanges134 are included alongsides110 for receiving fasteners holding top108 tomodule100. Mounted withininterior116 along one of thesides110 issplitter42. Anoptical fiber136 fromcable102 extends intointerior116 throughfront106.Fiber136 is formed into aloop138 withininterior116 before being directed to a first end ofsplitter42. An outer jacket ofcable102 is terminated at and constrained to aboot140 attached tofront106.Fiber136 extends throughloop138 tosplitter42 aboutinterior116 to ensure that minimum bend radius requirements to avoid excessive signal loss are maintained. One ormore cable clips142 are mounted tobottom112 to aid in the layout ofcable136 withininterior116.
• Any contraction of the jacket ofcable102 might result in the formation ofexcess length15 offiber136.Loop138 provides a place to accumulate any suchexcess length15 and avoid the creation of undesirably tight bends offiber136 withinmodule100 orcable102.
• A plurality ofribbon cables144 extend fromsplitter42opposite fiber136.Splitter42 separates the optical signals carried byfiber136 into up to thirty-two individual optical signals. Eachribbon cable144 may include up to eightfibers146, each fiber carrying one of those optical signals.Ribbon cables144 extend fromsplitter42 to mountingholders104 infront106.Ribbon cables144 form aloop148 withininterior116 betweensplitter42 andholders104. Cable clips142 are provided to aid in the routing and organization ofloop148 ofcables144 andcables146 withininterior116.Loop148 is shown inribbon cables144 withfibers146 being broken out fromribbon cables144 shortly beforefibers146enter openings126 ofholders104. Alternatively,individual fibers146 could extend fromsplitter42 aboutloop148 with no ribbon cables included withininterior116.
• Fibers146 are freely slidable within jackets ofcables118 and both the jacket andfibers146 are terminated and constrained atconnector119.Cables118 are also constrained atholders104, as will be described further below.Fibers146 extend throughholder104 toribbon cables144 andribbon cables144 are constrained atsplitter42. In one alternative wherefibers146 extend fromholders104 tosplitter42,fibers146 are constrained atsplitter42. Anyexcess length15 offiber146 withincable118 created due to contraction of the jacket ofcable118 is accumulated withininterior116 byloop148.
• FIG. 13 shows a generalized top view of the elements withininterior116. Only one of theribbon cables144 is shown completely and it should be understood that theother ribbon cables144 are similarly constructed. At anend145 ofribbon cable144individual fibers146 are broken out. Only threefibers146 are shown for clarity.Fibers146 extend through anopening126 of one of theholders104 within afurcation tube assembly148.
• FIG. 14 shows aninner face105 ofholder104 with onefurcation tube assembly148 within one of theopenings126.Furcation tube assembly148 includes a hollowinner tube150 and a hollowouter tube152.Outer tube152 includes an opening within whichinner tube150 in inserted. Other elements may also be included within the opening ofouter tube152 aboutinner tube150. These elements may include but are not limited to strength members or similar elements.Inner tube150 includes an opening through whichfiber146 may be slidably inserted.
• FIGS. 15 and 16 show furcatingtube assembly148 in additional detail, including a mountingcollar154 with a front portion153 sized to be inserted within one of theopenings126 ofholder104. Front portion153 may be slightly oversized within respect to opening126 to promote a friction fit withinopening126. Alternatively, an adhesive or some mechanical means may be used to secure mountingcollar154 withinopening126. Mountingcollar154 includes a central hollow opening through whichinner tube150 extends. Arear portion155 of mountingcollar154 is sized to extend within the opening ofouter tube152 aboutinner tuber150. Astrength member158 is shown inFIG. 16 extending from betweeninner tube150 andouter tube152.Strength member158 as shown is an aramnid fiber such as Kevlar but other suitable materials may also be used. Whenrear portion155 is positioned betweeninner tube150 andouter tube152,strength member158 is overlapped ontorear portion155. Acrimp sleeve156 is fit aboutouter tube152 aboverear portion155 of mountingcollar154 and crimped to hold these elements together. An adhesive may also be applied atlocation160 whereinner tube150 extends through mountingcollar154 to ensure thatinner tube150 remains fixed withinassembly148.
• FIGS. 17 and 18 show additional details ofinput fiber102 andboot140 and their assembly tomodule100. Anopening162 infront105 receives an insert164 and a threadedportion163 of acable mount166 fromoutside module100. Within interior116 awasher168 and anut170 are placed over threadedportion163 ofmount166 andsecure mount166 tofront106. InFIG. 17, an outer jacket assembly177 forinput cable102 includes a hollowinner tube174 with an opening to receiveoptical fiber136. A hollowouter tube176 is positioned aboutinner tube174 and astrength member178 is positioned between the inner and outer tubes.
• Inner tube174 is inserted throughcable mount166 so thatstrength member178 is positioned about as crimp portion ofcable mount166. Acrimp sleeve172 is positionedouter tube176 andstrength member178 and crimped aboutcrimp portion165 to hold these elements together.Boot140 is positioned aboutcrimp sleeve172 to provide strain relief and protection tocable102 and its connection tomodule100.
• FIGS. 19 to 22 illustrate afiber optic device200 with a firstoptical fiber cable202 on afirst side204 of ahousing206 and a secondoptical fiber cable208 on asecond side210 ofhousing206. As shown,first side204 and second210 are opposite sides ofhousing206. Referring now toFIG. 22,housing206 defines a fiber receiving device which may include acover212 fitting to anopen body portion214 and defining an interior216.First cable202 may include an outer sheath orjacket201 and aninner opening203 for receiving at least one optical fiber.Outer jacket201 may be terminated with respect toside204 at an extension or fitting226 so that opening203 is in communication with anopening222 ofhousing206 to permit anoptical fiber230 within opening203 to pass intointerior216.Second cable208 may be similarly configured with anouter jacket207 defining aninner opening209.Outer jacket207 may be terminated to an extension or fitting228 ofside210 so thatoptical fiber230 may extend frominterior space216 intoinner opening209.
• Fittings226 and228 may be similarly constructed and formed as separate pieces which may be positioned withinopenings222 and224, respectively. Havingfittings226 and228 are separate items fromhousing206 permits attachment ofouter jackets201 and207 to the fittings and then have the combination offittings226 and228, andcables202 and208 positioned withinopen body portion214. This may aid in the accuracy and ease of assembly.Device200 may be assembled into an intermediate point of a cable assembly which is then terminated, such as by a connector, at both ends, in a similar fashion as shown inFIG. 8, above. The connection ofcables202 and208 tofittings226 and228, respectively, may be a primarily mechanical connection, such as may be shown withfittings226 and228, or may be aided or secured by an adhesive, such as may be shown in the embodiment below.
• Withininterior216,fiber230 may extend from opening222 directly to opening224 or it may extend withininterior space216 about acentral support218 creating aloop232 of excess fiber length. Ifouter jacket201 and/orouter jacket207 are exposed to temperature extremes that may result in differential shrinking of the outer jackets with respect tofiber230,loop232 may accept any additional slack and prevent microbending, as discussed above with regard toFIG. 3. Conversely, ifouter jackets201 and/or207 expand at a greater rate thanfiber230 when exposed to temperature extremes,loop232 may provide sufficient excess length to offset any differential and preventfiber230 from being placed under excess tension.
• Central structure218 is shown as including atab220 which may assist with the placement and securing offiber230 andloop232 withininterior216 during assembly ofdevice200 or during later repairs and reassembly.More tabs220 may be included incentral structure218. As shown, cover212 may be held to openbody214 by removably fasteners such as screws withinopenings234, or cover212 may be more permanently fixed tobody214.Central support218 is preferably large enough in diameter to provide minimum bend radius protection tofiber230 during any changes in temperature which may absorb some offiber230 inloop232. Anouter wall236 defines an outer limit to a cable routing path withininterior216 withcentral support218 defining an inner limit of the cable routing path. Openings235 ofhousing206 extend through the housing and allow fasteners (for example, screws or bolts, not shown) extending through openings235 to mount or attachdevice200 to another optical component, an equipment rack, or similar structure.
• Device200 may be assembled by beginning with firstoptical fiber cable202 withoptical fiber230 extending within opening203 ofouter jacket201.Optical fiber230 includes afirst end242 and asecond end244. Firstouter jacket201 includes afirst end238 and asecond end240. First ends238 and242 are constrained with respect to each other, such as at a termination or a connector.Second end244 ofoptical fiber230 is extended beyondsecond end240 of firstouter jacket201.Second end244 offiber230 is passed throughopening222 and fitting226 andsecond end240 ofjacket201 is connected to fitting226. Afirst end246 ofsecond cable jacket207 is connected to fitting228.Fiber230 is passed throughinterior216 and extended throughopening224, fitting228, and intoinner opening209 ofsecond cable208.Second end244 offiber230 may also be constrained with respect to asecond end248 ofcable jacket207.
• Referring now toFIGS. 23 to 27, a second embodiment of afiber optic device300 according to the present invention includeshousing306 with a firstfiber optic cable302 on afirst side304 and a plurality of secondoptical fiber cables308 on asecond side310.First cable302 may include a plurality ofoptical fibers330 within aninner opening303 surrounded by anouter jacket301. Aloop332 of thesefibers330 is shown extending into an interior316 defined acover312 and an opensided body314. Withininterior316,loops332 offibers330 may extend about aninterior support318 and be held in place by one ormore tabs320.Second cables308 may be upjackets, such as a 2 mm standard jacket, into whichfibers330 are inserted. Alternatively, other types and styles of break out jacketing forfibers330 may be used. Only onefiber330 and oneloop332 is shown for illustration purposes, but it anticipated that a plurality offibers330 may be extend withinfirst cable302 and form a plurality ofloops332 withininterior316 aboutcentral support318.
• Outer jacket301 offirst cable302 is anchored tofirst side304 at a fitting326 which terminatesouter jacket301 tohousing314.Outer jackets307 ofsecond cables308 are terminated atsecond side310 by a fitting328.Fibers330 extend frominner opening303 offirst cable302 through anopening322 intointerior316, and may extend aboutinterior support318 before being directed through anopening324 and into one of thesecond cables308. Only onefiber330 is shown as an example andother fibers330 have been removed for clarity ofFIG. 26.
• Fittings326 and328 may be formed as separate elements fromhousing306 and may be separately attached toouter jackets301 and307 ofcables302 and308, respectively. Fitting326 may be similarly configured to fitting226, shown inFIG. 22, above, for connection toouter jacket307 ofcable302. The plurality offibers332 withincable202 are then separated withinhousing306 and directed each to one of thecables308.Outer jackets307 ofcables308 may be pre-connected or mounted to fitting328 so that each of thefibers330 may be inserted within one of theouter jackets307 prior to assembly offittings326 and328 withinhousing portion314. The connection ofcables302 and308 tofittings326 and328, respectively, may be a primarily mechanical connection, such as may be shown with fitting326, or may be secured by an adhesive, such as may be shown withfitting328.
• Optical device300 provides protection tofibers330 in generally the same manner asoptical device200, allowing excess length offiber330 with respect toouter jackets301 and307 to be stored withininterior316. Anouter wall336 defines an outer limit to a cable routing path withininterior316 andcentral support318 defines an inner limit of the cable routing path.Cable302 andcables308permit fibers330 to enter and exit frominterior316 and the cable routing path on opposite sides ofhousing306.
• A third alternative embodiment of afiber optic device400, shown inFIGS. 28 to 31, includes a firstfiber optic cable402 and a plurality of secondfiber optic cables408 which are both on afirst side404 of ahousing406.Housing406 includes anopen body portion414 and acover412 defining an interior416. Acentral support418 is positioned withininterior416 and cooperates with anouter wall436 to define a cable routing path for aloop432 of afiber430 extending fromfirst cable402 to one of thesecond cables408. Asingle fiber430 forming asingle loop432 is shown to illustrate routing offiber430 withininterior418. It is anticipated that acable402 may include a plurality offibers430 and thesefibers430 may form a plurality ofloops432 withininterior416 aboutcentral support418.
• A fitting426 is provided at afirst opening422 inside404 to anchor anouter jacket401 ofcable402 tohousing406 andpermit fibers430 to pass from aninner opening403 ofcable402 intointerior416. A fitting428 is provided at asecond opening424 inside404 to anchorsecond cables408 tohousing406 andpermit fiber430 to pass from interior416 intocables408. Configuringhousing406 with first andsecond openings422 and424 on thesame side404, as opposed toopposite sides204 and210 oropposite sides304 and310, different cable routing requirements within a particular optical fiber installation may be supported. It is anticipated thatfittings426 and428 are similarly configured tofittings326 and328, respectively, as described above. It is also anticipated that a further alternative embodiment may include asingle cable408 and may direct asingle fiber430 fromcable402 to thesingle cable408, similar todevice200, shown above. In this embodiment, fitting426 may be similarly configured to fitting226, described above.
• As shown indevices300 and400,cables302 or402 may be a multiple fiber cable including, for example, twelve individualoptical fibers330 or430. For this example, up to twelvecables308 and408 may be provided to protect theseindividual fibers330 or430 from thermal expansion or contraction effects and direct thefibers330 or430 to other devices or equipment. Other numbers ofoptical fibers330 and430 may be included withincables302 and402, andfittings328 and428 may be modified to alter the number of mounts forcables308 and408 extending fromhousings306 and406, respectively. Each of thedevices200,300 and400 include an open sided body portion and removable cover enclosing an interior. Such a configuration may installed on a fiber optic cable either in the field or as part of an original configuration assembled in a factory or workshop. This type of configuration also permits access to the interior for repair or replacement of fibers or components within the interior. Alternatively, the cover may be permanently affixed to the body portion once the device has been assembled, if it is intended that the device not be repairable, or if is desirable to secure the interior against tampering or contamination.
• First cables302 and402 are shown as multi-fiber round cables. Alternatively,devices300 and400 may be adapted to receive first cables which are multi-fiber ribbon cables. Thefirst cables202,302 and402 may be terminated at an endopposite devices200,300 and400, respectively, so that the optical fiber and the outer jacket are fixed with respect to each other at that end, such as shown inFIG. 4, above.Second cable208 may be terminated at an end oppositedevice200, as shown inFIG. 4, above.Second cables308 and408 may be each terminated by a connector, such as shown inFIG. 10.
• Referring now toFIGS. 26 and 27, fitting326 includes a body with a first end adapted to be inserted withincable housing301. The body also includes a second end adapted for positioning withinopening322 and a recess between the first and second ends to engage a mating portion ofhousing portion314 and hold fitting326 withinopening322. An axial channel defined longitudinally through body permits passage offiber303 fromcable302 intohousing306. First end may include one or more barbs or other ridges to aid body in gripping an inner wall ofouter jacket301.
• Fitting328 includes a body with a plurality of openings into which are extended ends of a plurality ofouter jackets307.Jackets307 may be glued, crimped or otherwise mechanically fixed to fitting328 so thatfibers330 can pass from withinhousing306 through the openings while being continually protected byouter jackets307. The body may include flanges extending along either or both of the top and bottom which may engage recesses within opening324 to secure fitting328 withinopening324.
• The above specification, examples and data provide a complete description of the manufacture and use of the invention. Since many embodiments of the invention can be made without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended.

Claims (13)

1. An optical fiber device comprising:

an optical fiber with a first end slidably enclosed within a first cable jacket and a second end slidably received within a second cable jacket, the first end of the fiber constrained with respect to the first cable jacket and the second end of the fiber constrained with respect to the second cable jacket;

wherein a fiber receiving device positioned between the first and second cable jackets permits the excess fiber length to accumulate without bending in a radius smaller than a minimum bend radius.

2. The optical fiber device ofclaim 1, wherein the fiber receiving device includes a housing with a open sided body portion and a cover defining an interior, the first and second cable jackets extending to a side of the housing and the optical fiber passing through the interior of the housing between the first and second cable jackets.

3. The optical fiber device ofclaim 2, wherein the optical fiber forms a loop within the interior.

4. The optical fiber device ofclaim 3, further comprising a central support within the interior, and wherein the loop of the optical fiber extends about the central support.

5. The optical fiber device ofclaim 4, wherein the central support provides bend radius protection to the optical fiber.

6. The optical fiber device ofclaim 1, wherein a plurality of fibers extend within the first cable jacket and into the fiber receiving device, and a plurality of second cable jackets each receive one of the optical fibers from within the fiber receiving device.

7. The optical fiber cable ofclaim 1, wherein the first end of the optical fiber and the first cable jacket are constrained with respect to each other at an optical fiber connector.

8. The optical fiber cable ofclaim 1, wherein the second end of the optical fiber and the second cable jacket are constrained with respect to each other at an optical fiber connector.

9. A method of assembling an optical fiber device comprising:

providing a first optical fiber cable with an optical fiber extending within an inner opening of a first outer jacket, the optical fiber and the first outer jacket each having a first end and a second ends, the first ends of the first outer jacket and the optical fiber constrained within respect to each other;

extending the second end of the optical fiber beyond the second end of the first outer jacket;

extending the second end of the optical fiber through a first opening into an interior of a fiber receiving device;

anchoring the second end of the first outer jacket to the side of the fiber receiving device at the first opening;

anchoring a first end of a second outer jacket of a second optical fiber cable to the fiber receiving device at a second opening;

extending the second end of the optical fiber from the interior through the second opening and into an inner opening of the second outer jacket.

10. The method ofclaim 9, wherein the second end of the first outer jacket and the first end of the second outer jacket are anchored to opposite sides of the fiber receiving device.

11. The method ofclaim 9, wherein the second end of the first outer jacket and the first end of the second outer jacket are anchored to the same side of the fiber receiving device.

12. The method ofclaim 9, wherein the first optical fiber cable includes a plurality of optical fibers extending within the first outer jacket into the fiber receiving device, and a plurality of second outer jackets each receive one of the optical fibers through the second opening of the fiber receiving device.

13. The method ofclaim 9, wherein the fiber receiving device includes a housing defining the interior and the interior includes a central support about which the optical fiber is extended.

Images