Flat drop cable with stranded buffer tubes

Abstract

A flat drop cable includes a jacket having a length that extends along a central longitudinal axis and defines a transverse cross-sectional profile having a thickness and a width. The thickness is less than the width. First and second GRP rods are embedded within the jacket. Three or four buffer tubes are embedded within the jacket, between the first and second GRP rods. The buffer tubes are stranded, and each includes a plurality of optical fibers. Even though the flat drop cable includes three or four buffer tubes, the flat drop cable is compatible with conventional clamps commonly used with a flat drop cable having a single buffer tube. The flat drop cable may be abutted to one or more empty micro-ducts and the elements surrounded by an extruded over-jacket.

Description

FLAT DROP CABLE WITH STRANDED BUFFER TUBESBACKGROUND OF THE INVENTION1. Field of the Invention

[0001] The present invention relates to a flat fiber optic drop cable with three or four buffer tubes located between first and second strength members. More particularly, the present invention has buffer tubes of reduced diameters, stranded together and occupying a space such that the overall footprint of the drop cable will be compatible with existing clamps, and tools, used in conjunction with a standard flat drop cable with a single buffer tube located between the first and second strength members.2. Description of the Related Art

[0002] A flat fiber optic drop cable is used in fiber optic networks, and often is the cable that extends from pole to pole and to a customer’s house or business. Such flat drop cables typically include one central buffer tube containing at least one optical fiber, and reinforcing members such as rods, like glass reinforced plastic (GRP) rods, embedded in the jacket on opposite sides of the buffer tube. U.S. Patent No. 6,542,674, which is herein incorporated by reference, discloses a flat drop cable of the type described above. Another example of a flat drop cable can be seen in the Assignee’s US Patent No. 10,649,165, which is herein incorporated by reference.

[0003] Figure 1 shows a flat drop cable 10 currently marketed by the Assignee. The flat drop cable 10 includes a jacket 14, a core formed as a buffer tube 20 disposed within the jacket 14. The flat drop cable 10 has a length L (into and out of the plane of Figure 1), a width W, and a thickness T. The flat drop cable 10 includes a central longitudinal axis 12 that extends along the length L of the flat drop cable 10.

[0004] The jacket 14 of the flat drop cable 10 has a transverse cross-sectional profile that is elongated such that the width W is larger than the thickness T. In the commercial embodiment, the width W is about 7.9 mm and includes opposing flat surfaces 26 and the thickness T is about 4.5 mm and includes opposing rounded surfaces 27. The transverse cross-sectional profile of the jacket 14 defines a minor axis 16 that extends parallel to the thickness T and a major axis 18 thatextends parallel to the width W. The minor and major axes 16 and 18 are perpendicular relative to one another and intersect at the central longitudinal axis 12 of the flat drop cable 10.

[0005] First and second reinforcing members 22 and 24, such as GRP rods, are positioned on opposite sides of the minor axis 16. In a preferred embodiment, the central longitudinal axis 12 is located in the center of the buffer tube 20 and is also the center of flat drop cable 10. Also in the preferred embodiment, the major axis 18 passes through the centers of the first and second reinforcing members 22 and 24 and the center of the buffer tube 20, and the minor axis 16 passes through the center of the buffer tube 20.

[0006] Referring to Figure 1, the buffer tube 20 of the flat drop cable 10 has an outer diameter of about 3 mm and includes a plurality of optical fibers 28 and a water blocking gel. Each of the optical fibers 28 can include a core, a cladding layer surrounding the core, and one or more polymeric coatings surrounding the cladding layer. In Figure 1, twenty-four optical fibers 28 are present within the buffer tube 20.

[0007] The optical fibers 28 would need to have unique color codings in order to distinguish each optical fiber 28 from the other optical fibers 28. Typically, twelve different colors are used in a first set of twelve optical fibers 28, and a same color coding is used in a second set of twelve optical fibers 28, while an extra color strip, e.g., black or white, is added to the second set of twelve optical fibers 28. Alternatively, the first set of twelve optical fibers 28 is helically wrapped by a thread of a first color and the second set of twelve optical fibers 28 has the exact same color set, but is helically wrapped by a thread of a second and different color as compared to the first color. There is room in the buffer tube 20 to add an additional twelve optical fibers 28, which may be helically wrapped by a thread of a third and different color, to produce a drop cable 10 with thirty-six optical fibers 28.

[0008] The first and second reinforcing members 22 and 24 extend along the length L of the flat drop cable 10 and are centered along the major axis 18 of the transverse cross-sectional profile of the flat drop cable 10. The first and second reinforcing members 22 and 24 provide the flat drop cable 10 with both tensile and compressive reinforcement. The first and second reinforcing members 22 and 24 can have a construction that includes epoxy reinforced withfiberglass, commonly known as glass reinforced plastic (GRP) rods or generically known as fiber reinforced plastic (FRP) rods.

[0009] The flat drop cable 10 of Figure 1 has enjoyed success in the market and a cottage industry of compatible tools and accessories are in the market to support the technician’s deployment and service of the flat drop cable 10. For example, Figure 2 shows a tool 30, made by Jonard Tools, which is used for cutting through the jacket 14 to the first and second reinforcing members 22 and 24. The tool 30 has a slot 31 sized to accept the drop cable 10 having a width W between 0.305 to 0.350 inches (about 7.75 to 8.89 mm) and a thickness T between 0.155 to 0.185 inches (about 3.94 to 4.70 mm). The tool 30 assists in “opening” the jacket 14 of the flat drop cable 10 to gain access to the buffer tube 20, so that the buffer tube 20 may be carefully removed from a length of the enclosed optical fibers 28. The tool 30 typically includes one or more razor blades which align to portions of the jacket 14 overlying the first and second reinforcing members 22 and 24. The razor blade or blades will cut completely through the jacket 14 and allow the jacket 14 to be peeled from the first and second reinforcing members 22 and 24, which greatly simplifies the ability of the technician to expose the buffer tube 20 without damaging the optical fibers 28 therein. More details concerning the tool 30 of Figure 2 can be found in US Patent No. 8,353, 107, which is herein incorporated by reference.

[0010] Figure 3 shows a first clamp 32 in accordance with a first embodiment of the prior art, which uses a wedging action to clamp onto the flat surfaces 26 of the jacket 14. Additional details concerning the first clamp 32 can be found in the Assignee’s Published US Application No. 2022 / 0352702, which is herein incorporated by reference. A shell 33 of the second clamp 32 has a width X of about 0.36 inches, e.g., about 9.2 mm. The first clamp 32 is also available in a larger and stronger version wherein the shell 33 has a width X of about 0.63 inches, e.g., about 16 mm. Figure 4 shows a second, plastic clamp 34 in accordance with a second embodiment of the prior art, which uses a wedging action to clamp onto the rounded surfaces 27 of the jacket 14.

[0011] It is also known in the prior art to provide a flat drop cable with more than one buffer tube. For example, Figure 5 shows a flat drop cable 36 with first and second buffer tubes 38 and 40 located between first and second reinforcing members 42 and 44. Each of the first and second buffer tubes 38 and 40 surrounds a respective plurality of optical fibers 46.

[0012] A jacket 48 surrounds the components of the flat drop cable 36. Because the first and second buffer tubes 38 and 40 are located side-by-side and each buffer tube 38 or 40 is approximately equal in diameter to a reinforcing member 42 or 44, a width W1 of the jacket 48 is larger than the width W of the flat drop cable 10 of Figure 1, while a thickness T of the flat drop cable 36 of Figure 5 may be approximately the same as the thickness T of the flat drop cable 10 of Figure 1. More details concerning the flat drop cable 36 of Figure 5 can be found in US Patent No. 8,805,144, which is herein incorporated by reference.

[0013] Figure 6 shows a flat drop cable 50 with six reduced diameter buffer tubes 52 in accordance with the prior art. The six buffer tubes 52 are located within a rectangular cavity 54. The cavity 54 is centered between first and second reinforcing members 56 and 58. Each of the six buffer tubes 52 surrounds a respective plurality of optical fibers 60.

[0014] A jacket 62 surrounds the components of the flat drop cable 50. Because of the expanded width of the cavity 54 to loosely hold six buffer tubes 52, a width W2 of the jacket 62 is larger than the width W of the flat drop cable 10 of Figure 1, while a thickness T of the flat drop cable 50 of Figure 5 may be approximately the same as the thickness T of the flat drop cable 10 of Figure 1. More details concerning the flat drop cable 50 of Figure 6 can be found in US Patent No. 7,471,862, which is herein incorporated by reference.SUMMARY OF THE INVENTION

[0015] The applicant has appreciated drawbacks with the designs of the flat drop cables of the prior art.

[0016] There is a need for a flat drop cable with thirty-six optical fibers, which may expand in the future to forty-eight optical fibers. The flat drop cable will be beneficial to a new fiber optic distribution system and architecture being developed and improved upon by the Assignee. In the distribution system, three groups of optical fibers are included within a single cable. A first grouping is referred to as point-to-point optical fibers, a second grouping is referred to as feeder optical fibers, and a third grouping is referred to as distribution optical fibers.

[0017] The cable is routed between housings which are spaced apart by relatively long distances, such as in a rural area. Housings may include one or more of passive optical powerspliters, subscriber ports, or other passive or active optical devices to which one or more optical fibers of the incoming flat drop cable are terminated and one or more optical fibers of the outgoing flat drop cable is terminated. More detail concerning the distribution system can be found in the Assignee’s pending Provisional Application Serial No. 63 / 604,434, filed November 30, 2023, and Provisional Application Serial No. 63 / 552,554, filed February 12, 2024, both of which are herein incorporated by reference.

[0018] Inside the housings, not all of the optical fibers of the flat drop cable need to be terminated. Typically, all of the optical fibers within at least one of the groupings, e.g., the feeder optical fibers, are not terminated within a housing and are simply “pass through” fibers, which enter and exit the housing without a termination. With the prior art design of Figure 1, when the buffer tube 20 of the flat drop cable 10 is opened, all of the optical fibers 28 therein are exposed. When the optical fibers 28 are exposed, there is an increased risk that the “pass through” optical fibers 28 will be damaged or subjected to a micro-bend, as the other optical fibers 28 are terminated. Further, it is difficult to distinguish between thirty-six different optical fibers, where twelve base colors are used and an added dashed line of black and / or white is added to the color coding, or where color coded helical threads are used to distinguish identically, colored optical fibers 28 in separate groupings.

[0019] The prior art flat drop cable 36 of Figure 5 is advantageous in that first and second groupings of optical fibers 46 may be included in the first and second buffer tubes 38 and 40, respectively. Therefore, if a certain grouping of optical fibers is not to be terminated within a housing, that buffer tube, e.g., the second buffer tube 40, need not be opened within the housing. This provides an increased level of protection for the second grouping of optical fibers 46 within the second buffer tube 40 passing through the housing.

[0020] The prior art flat drop cable 50 of Figure 6 has the same advantage in that up to six groupings of optical fibers 60 may be included in the six buffer tubes 52, respectively. Therefore, if a certain grouping of optical fibers 60 is not to be terminated within a housing, that buffer tube 52 need not be opened within the housing. This provides an increased level of protection for the grouping of optical fibers 60 within the buffer tube(s) 52 passing through the housing.

[0021] However, the prior art designs of Figures 5 and 6 have drawbacks. The cross sections of the flat drop cables 36 and 50 will not function with the tools and accessories, e.g., clamps, which are currently in the market to support the technician’s deployment and service of the flat drop cable 10 of Figure 1. For example, the one or more razor blades of the tool 30 in Figure 2, which align to portions of the jacket 14 overlying the first and second reinforcing members 22 and 24 in Figure 1, will not align to the first and second reinforcing members 42 and 44 in Figure 5, and will not align to the first and second reinforcing members 56 and 58 in Figure 6. Further, the widths W1 and W2 of the flat drop cables 36 and 50 are too wide to fit into the clamps 32 and 34 shown in Figures 3 and 4. It would be expensive and burdensome for a technician to carry multiple tools and multiple sized clamps for flat drop cables.

[0022] The flat drop cable 36 of Figure 5 has all of the buffer tubes 38 and 40 linearly aligned between the first and second reinforcing members 42 and 44. If three buffer tubes were aligned between the first and second reinforcing members 42 and 44 to allow for three groupings of optical fibers, and the flat drop cable 36 were gradually bowed over a long distance about the minor axis 16 (Figure 1), the buffer tube on the inside of the bow would undergo compression and the buffer tube on the outside of the bow would undergo expansion. Excess fiber length within the buffer tube undergoing expansion could accommodate some expansion, however excessive expansion or a slight bow over a very long length could lead to damage or breakage to the optical fibers within the buffer tube on the outside of the bow and a micro-bend of optical fibers within the buffer tube on the inside of the bow.

[0023] The flat drop cable 50 of Figure 6 has an oversized rectangular cavity 54, which holds the six buffer tubes 52. The cavity 54 has gaps to the right and left of the buffer tubes 52, which would allow the buffer tubes 52 to slide to the side of the cavity 54 which resides on the inside of a long bow of the flat drop cable 50. Hence, the large cavity 54 is better suited to avoid the issues of damage, breakage and micro-bends to the optical fibers 60 if the flat drop cable 50 is bowed over a long distance about the minor axis 16 (Figure 1). However, the oversized cavity 54 would require an excessive and expensive amount of water-blocking gel and / or water booking threads, tapes or powder.

[0024] It is an object of the present invention to address one or more of the drawbacks of the prior art flat drop cables of Figures 1, 5 and 6.

[0025] It is an object of the present invention to provide a flat drop cable which includes three or four buffer tubes stranded together with the stranded buffer tubes residing between first and second reinforcing members.

[0026] It is an object of the present invention to provide a flat drop cable wherein a diameter of the grouping of the three stranded buffer tubes and a spacing between first and second reinforcing members on opposing sides of the stranded buffer tubes allow conventional tools and accessories, like clamps, to be used in conjunction with the flat drop cable.

[0027] These and other objectives are accomplished by a flat drop cable including a jacket having a length that extends along a central longitudinal axis and defines a transverse cross- sectional profile having a thickness and a width. The thickness is less than the width. First and second GRP rods are embedded within the jacket. Three or four buffer tubes are embedded within the jacket, between the first and second GRP rods. The buffer tubes are stranded, and each includes a plurality of optical fibers. Even though the flat drop cable includes three or four buffer tubes, the flat drop cable is compatible with conventional clamps commonly used with a flat drop cable having a single buffer tube. The flat drop cable may be abutted to one or more empty micro-ducts and the elements surrounded by an extruded over-jacket.

[0028] Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.BRIEF DESCRIPTION OF THE DRAWINGS

[0029] For a better understanding of the invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:

[0030] Figure 1 is an end view of a flat drop cable currently being offered for sale by the Assignee, in accordance with the prior art;

[0031] Figure 2 is a perspective view of a tool used in conjunction with the cable of Figure 1, in accordance with the prior art;

[0032] Figure 3 is a perspective view of a first type of clamp used in conjunction with the cable of Figure 1, in accordance with the prior art;

[0033] Figure 4 is a perspective view of a second type of clamp used in conjunction with the cable of Figure 1, in accordance with the prior art;

[0034] Figure 5 is a perspective view of an end of a flat drop cable having two buffer tubes, in accordance with the prior art;

[0035] Figure 6 is a cross sectional view of a flat drop cable having six buffer tubes, in accordance with the prior art;

[0036] Figure 7 is an end view of a flat drop cable, in accordance with the present invention;

[0037] Figure 8 is a perspective view of a stranding of three buffer tubes prior to having a jacketing material extruded thereon;

[0038] Figure 9 is an end view of a flat drop cable constructed the same as Figure 7, but including a messenger wire;

[0039] Figure 10 is an end view of a flat drop cable, in accordance with a first alternative embodiment of the present invention;

[0040] Figure 11 is an end view of a flat drop cable, in accordance with a second alternative embodiment of the present invention;

[0041] Figure 12 is an end view of a flat drop cable, in accordance with a third alternative embodiment of the present invention;

[0042] Figure 13 is an end view of a flat drop cable upjacketed to two micro-ducts;

[0043] Figure 14 is an end view of a flat drop cable upjacketed to four micro-ducts; and

[0044] Figure 15 is an end view of a flat drop cable upjacketed to six micro-ducts.DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0045] The present invention now is described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0046] Like numbers refer to like elements throughout. In the figures, the thickness of certain lines, layers, components, elements or features may be exaggerated for clarity. Broken lines illustrate optional features or operations unless specified otherwise.

[0047] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the specification and relevant art and should not be interpreted in an idealized or overly formal sense unless expressly so defined herein. Well-known functions or constructions may not be described in detail for brevity and / or clarity.

[0048] As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. As used herein, phrases such as "between X and Y" and "between about X and Y" should be interpreted to include X and Y. As used herein, phrases such as "between about X and Y" mean "between about X and about Y." As used herein, phrases such as "from about X to Y" mean "from about X to about Y."

[0049] It will be understood that when an element is referred to as being "on", "attached" to, "connected" to, "coupled" with, "contacting", etc., another element, it can be directly on, attached to, connected to, coupled with or contacting the other element or intervening elements may also be present. In contrast, when an element is referred to as being, for example, "directly on", "directly attached" to, "directly connected" to, "directly coupled" with or "directly contacting" another element, there are no intervening elements present. It will also be appreciated by those of skill in the art that references to a structure or feature that is disposed "adjacent" another feature may have portions that overlap or underlie the adjacent feature.

[0050] Spatially relative terms, such as “under”, “below”, “lower”, “over”, “upper”, “lateral”, “left”, “right” and the like, may be used herein for ease of description to describe one element or feature’s relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is inverted, elements described as “under” or “beneath” other elements or features would then be oriented “over” the other elements or features. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the descriptors of relative spatial relationships used herein interpreted accordingly.

[0051] Figure 7 shows an end view of a flat drop cable 110, in accordance with the present invention. The flat drop cable 110 includes a jacket 114, a core 120 embedded within the jacket 114, and first and second reinforcing members 122 and 124 embedded within the jacket 114. The flat drop cable 110 has a length L (into and out of the plane of Figure 7), a width W, and a thickness T, which may be the same as the width W and thickness T shown in Figure 1. The flat drop cable 110 includes a central longitudinal axis 12 that extends along the length L of the flat drop cable 110.

[0052] The jacket 114 of the flat drop cable 110 extends along the central longitudinal axis 12 and has a transverse cross-sectional profde (shown in Figure 7). The profile is elongated such that the width W is larger than the thickness T. The jacket 114 of the fiber optic cable 110 includes opposite top and bottom sides 126, 126A which are generally flat and parallel to each other, and that extend between opposite rounded ends 127, 127A. The thickness T of the fiber optic cable110 extends between the top and bottom sides 126, 126A, while the width W of the fiber optic cable 110 extends between the rounded ends 127, 127A.

[0053] The width W is 7.9 mm plus or minus ten percent, such as between 7.5 to 8.5 mm. In a preferred embodiment, the width W is about 7.9 mm, so that the drop cable 110 is compatible with the clamps 32 and 34 of Figures 3 and 4, and so that the first and second reinforcing members 122 and 124 align to the razor blades of the tool 30. The thickness T is 4.5 mm plus or minus about ten percent. In a preferred embodiment, the thickness T is about 4.5 mm, so that the drop cable 110 is compatible with the clamps 32 and 34 of Figures 3 and 4.

[0054] The transverse cross-sectional profile of the jacket 114 defines a minor axis 16 that extends along the thickness T and a major axis 18 that extends along the width W. The minor and major axes 16 and 18 are perpendicular to one another and also perpendicular to the central longitudinal axis 12, and intersect at the central longitudinal axis 12 of the flat drop cable 110.

[0055] The first and second reinforcing members 122 and 124 extend along the length L of the fiber optic cable 110 and are aligned along the maj or axis 18 of the transverse cross-sectional profile of the fiber optic cable 110. More particularly, the major axis 18 passes through the centers of the first and second reinforcing members 122 and 124. As depicted in Figure 7, the first and second reinforcing members 122 and 124 are positioned on opposite sides of the minor axis 16 of the transverse cross-sectional profile of the fiber optic cable 110 and spaced equal distances away from the minor axis 16.

[0056] In certain examples, the first and second reinforcing members 122 and 124 can be configured to provide the fiber optic cable 110 with both tensile and compressive reinforcement. In certain examples, the first and second reinforcing members 122 and 124 can have a construction that includes epoxy reinforced with fiberglass, bamboo, animal hair, short metal strands, short aramid strands or other types of fibers, whether natural or manmade. In a preferred embodiment, the first and second reinforcing members 122 and 124 are each formed as a glass reinforced plastic (GRP) rod. In other examples, the first and second reinforcing members 122 and 124 can include solid metal rods, stranded metal wires or other structures.

[0057] The core 120 of the flat drop cable 110 is generally centered about and extends along the central longitudinal axis 12, between the first and second reinforcing members 122 and124. In a preferred embodiment, the central longitudinal axis 12 is located in the center of the core 120, which is also the center of fiber optic cable 110. Also, in the preferred embodiment, the major axis 18 passes through the centers of the first and second reinforcing members 122 and 124 and the core 120, and the minor axis 16 passes through the center of the core 120.

[0058] The core 120 includes plural buffer tubes. In the depicted preferred embodiment, exactly three buffer tubes, i.e., first, second and third buffer tubes 130, 132 and 134 are embedded within the jacket 114. It is noted that the three buffer tubes 130, 132 and 134 are not linearly aligned with each other between the first and second reinforcing members 122 and 124. Rather, the three buffer tubes 130, 132 and 134 are stranded together to form the core 120. The three buffer tubes 130, 132 and 134 are preferably helically stranded together and require no binders. However, the three buffer tubes 130, 132 and 134 may alternatively be SZ stranded together, in which case one or two binder threads or tapes may encircle the core 120 to hold the core 120 together during manufacturing of the flat drop cable 110.

[0059] Each of the first, second and third buffer tubes 130, 132 and 134 includes a plurality of optical fibers 128, such as at least eight optical fibers 128. In the embodiment depicted in Figure 7, each of the first, second and third buffer tubes 130, 132 and 134 includes at least twelve optical fibers 128. However, each of the first, second and third buffer tubes 130, 132 and 134 may include more or fewer optical fibers 128, such as six or sixteen optical fibers 128. The optical fibers 128 each typically include a core, a cladding layer surrounding the core, and one or more polymeric coatings surrounding the cladding layer. The optical fibers may all be of a single mode type, may all be of a multimode type, or may be a mixture of the two types. The optical fibers may all be a same diameter or may be of different diameters. Although the optical fibers 128 are shown as loose within the three buffer tubes 130, 132 and 134, the optical fibers 128 may be ribbonized, e g., connected to each other by a flat, rolled or collapsible ribbon.

[0060] A diameter of each of the three buffer tubes 130, 132 and 134 is about 1.45 mm plus or minus ten percent, more preferably plus or minus three percent. This results in an overall core diameter of 3 mm plus or minus ten percent, most preferably about 3 to 3.2 mm. As shown in Figure 7, the central longitudinal axis 12 does not pass through any of said three buffer tubes, however this is not essential to the invention.

[0061] Figure 8 is a perspective view of a stranding of the three buffer tubes 130, 132 and 134 prior to having the jacket 114 extruded thereon. A lay or strand length S of the core 120 is greater than 12 inches, such as about 20 to 50 inches. In a preferred embodiment, the strand length S of the core 120 is about 25 to 35 inches, e.g., about 30 inches.

[0062] In a preferred embodiment of the flat drop cable 110, each of the three buffer tubes 130, 132 and 134 is extruded from a colored material, which distinguishes it from the other two buffer tubes. For example, the first buffer tube 130 may be extruded from a blue dyed polymer, the second buffer tube 132 may be extruded from a yellow dyed polymer and the third buffer tube 134 may be extruded from a green dyed polymer. Alternatively, each of the three buffer tubes 130, 132 and 134 may include a color stripe, e.g., blue, green or yellow, which distinguishes it from the other two buffer tubes.

[0063] As shown in Figure 7, the flat drop cable 110 may further include one or more water-blocking tapes or threads 136 abutting the core 120. The water-blocking tapes or threads 136 may be located within one or more of the interstices 138 where the extruded material forming the jacket 114 leaves an air gap. Such water-blocking tapes or threads 136 may be stranded along with the core 120 in Figure 8. Stranding the water-blocking tapes or threads 136 may cause them to locate into the central interstice 138, along or proximate the central longitudinal axis 12. Water blocking tapes of threads may also be provided within the three buffer tubes 130, 132 and 134. Instead of the water-blocking tapes or threads 136 (or in addition thereto), SAP powder or a waterblocking gel, may be used, although such alternatives or supplements are not preferred.

[0064] As shown in Figure 7, the flat drop cable 110 may further include one or more rip cords 140 abutting the core 120. The rip cords 140 may be located within the same interstices 138 where the water blocking tapes or threads 136 are located. The rip cords 140 may be stranded along with the core 120 in Figure 8. The rip cord 140 may be constructed of polyester, aramid fibers, like KELVAR, or even a stranded metal wire.

[0065] Figure 9 is an end view of a flat drop cable 110A, constructed the same as Figure 7, but including a messenger wire 142, which may be used to support the flat drop cable 110A in a long-span aerial deployment. The messenger wire 142 includes a stranded or solid metal core, e.g., a solid, steel core 144, which is covered by an insulation layer 146. In a preferred embodiment,the insulation layer 146 is integrally extruded along with the material forming the jacket 114, when the flat drop cable 110A is manufactured. The interconnecting web 148 may include one or more indentations 150 to facilitate separating the messenger wire 142 from the jacket 114.

[0066] Figure 10 is an end view of a flat drop cable HOB, constructed similarly to the flat drop cable 110 of Figure 7, in accordance with a first alternative embodiment of the present invention. The Flat drop cable HOB includes larger components and / or dimensions, which may permit the flat drop cable 11 OB to be used in a long-span aerial deployment, e.g., exceeding two hundred feet.

[0067] The flat drop cable HOB includes a jacket 114B, a core 120B embedded within the jacket 114B, and first and second reinforcing members 122B and 124B embedded within the jacket 114B. The flat drop cable HOB has a length (into and out of the plane of Figure 10), a width W3, and a thickness Tl, which are larger than the width W and thickness T shown in Figures 1 and 7. The flat drop cable HOB includes a central longitudinal axis 12 that extends along the length of the flat drop cable HOB.

[0068] The jacket 114B of the flat drop cable 110B extends along the central longitudinal axis and has a transverse cross-sectional profile (shown in Figure 10). The profile is elongated such that the width W3 is larger than the thickness Tl . The jacket 114B of the fiber optic cable HOB includes opposite top and bottom sides 226, 226 A which have a radius of curvature, and that extend between opposite rounded ends 227, 227A, which have a smaller radius of curvature as compared to the top and bottom sides 227 and 227A. The thickness Tl of the fiber optic cable HOB extends between the top and bottom sides 226, 226 A, while the width W3 of the fiber optic cable HOB extends between the rounded ends 227, 227A.

[0069] The width W3 is 9.4 mm plus or minus ten percent, such as between 8.5 to 10.3 mm. In a preferred embodiment, the width W3 is about 9.4 mm, so that the drop cable HOB is compatible with the larger and stronger clamp 32 of Figure 3, which has a shell 33 with a width X of about 16 mm. The thickness Tl is 4.5 mm plus or minus about ten percent. In a preferred embodiment, the thickness Tl is about 4.5 mm, so that the drop cable 110 is compatible with the clamp 32 of Figure 3.

[0070] The transverse cross-sectional profile of the jacket 114B defines a minor axis 16 that extends along the thickness T1 and a major axis 18 that extends along the width W3. The minor and major axes 16 and 18 are perpendicular to one another and also perpendicular to the central longitudinal axis 12, and intersect at the central longitudinal axis 12 of the flat drop cable HOB.

[0071] The first and second reinforcing members 122B and 124B extend along the length L of the fiber optic cable HOB and are aligned along the major axis 18 of the transverse cross- sectional profile of the fiber optic cable HOB. More particularly, the major axis 18 passes through the centers of the first and second reinforcing members 122B and 124B. As depicted in Figure 10, the first and second reinforcing members 122B and 124B are positioned on opposite sides of the minor axis 16 of the transverse cross-sectional profile of the fiber optic cable HOB and spaced equal distances away from the minor axis 16.

[0072] In certain examples, the first and second reinforcing members 122B and 124B can be configured to provide the fiber optic cable 110 with both tensile and compressive reinforcement. In certain examples, the first and second reinforcing members 122B and 124B can have a construction that includes epoxy reinforced with fiberglass, bamboo, animal hair, short metal strands, short aramid strands or other types of fibers, whether natural or manmade. In a preferred embodiment, the first and second reinforcing members 122B and 124B are each formed as a glass reinforced plastic (GRP) rod and have a diameter of 2.3 mm. In other examples, the first and second reinforcing members 122B and 124B can include solid metal rods, stranded metal wires or other structures.

[0073] The core 120B of the flat drop cable HOB is generally centered about and extends along the central longitudinal axis 12, between the first and second reinforcing members 122B and 124B. In a preferred embodiment, the central longitudinal axis 12 is located in the center of the core 120B, which is also the center of fiber optic cable HOB. Also, in the preferred embodiment, the major axis 18 passes through the centers of the first and second reinforcing members 122B and 124B and the core 120B, and the minor axis 16 passes through the center of the core 120B.

[0074] The core 120B includes plural buffer tubes. In the depicted preferred embodiment, exactly three buffer tubes, i.e., first, second and third buffer tubes BOB, 132B and 134B areembedded within the jacket 114B. It is noted that the three buffer tubes 130B, 132B and 134B are not linearly aligned with each other between the first and second reinforcing members 122B and 124B. Rather, the three buffer tubes 130B, 132B and 134B are stranded together to form the core 120B. The three buffer tubes BOB, 132B and 134B are preferably helically stranded together and require no binders. However, the three buffer tubes BOB, 132B and 134B may alternatively be SZ stranded together, in which case one or two binder threads or tapes may encircle the core 120B to hold the core 120B together during manufacturing of the flat drop cable HOB.

[0075] Each of the first, second and third buffer tubes BOB, 132B and 134B includes a plurality of optical fibers 128, such as at least eight optical fibers 128. In the embodiment depicted in Figure 10, each of the first, second and third buffer tubes BOB, 132B and 134B includes at least twelve optical fibers 128. However, each of the first, second and third buffer tubes BOB, 132B and 134B may include more or fewer optical fibers 128, such as six or sixteen optical fibers 128.

[0076] A diameter of each of the three buffer tubes BOB, 132B and 134B is about 1.5 mm plus or minus ten percent, more preferably plus or minus three percent. This results in an overall core diameter of 3.1 mm plus or minus ten percent, most preferably about 3.1 mm. As shown in Figure 10, the central longitudinal axis 12 does not pass through any of said three buffer tubes, however this is not essential to the invention. The stranding of the three buffer tubes BOB, 132B and 134B prior to having the jacket 114B extruded thereon would look like Figure 8. A lay or strand length S of the core 120B is greater than 12 inches, such as about 20 to 50 inches. In a preferred embodiment, the strand length S of the core BOB is about 25 to 35 inches, e.g., about 30 to 32 inches.

[0077] In a preferred embodiment of the flat drop cable HOB, each of the three buffer tubes BOB, 132B and 134B is extruded from a colored material, which distinguishes it from the other two buffer tubes. Alternatively, each of the three buffer tubes BOB, 132B and 134B may include a color stripe, e.g., blue, green or yellow, which distinguishes it from the other two buffer tubes.

[0078] As shown in Figure 10, the flat drop cable HOB may further include one or more water-blocking tapes or threads 136 abutting the core 120B. The water-blocking tapes or threads 136 may be located within one or more of the interstices 138 where the extruded material formingthe jacket 114B leaves an air gap. Such water-blocking tapes or threads 136 may be stranded along with the core 120B. Stranding the water-blocking tapes or threads 136 may cause them to locate into the central interstice 138, along or proximate the central longitudinal axis 12. Water blocking tapes of threads may also be provided within the three buffer tubes I 30B, 132B and 134B. Instead of the water-blocking tapes or threads 136 (or in addition thereto), SAP powder or a water-blocking gel, may be used, although such alternatives or supplements are not preferred.

[0079] As shown in Figure 10, the flat drop cable HOB may further include one or more rip cords 140 abutting the core 120B. The rip cords 140 may be located within the same interstices 138 where the water blocking tapes or threads 136 are located. The rip cords 140 may be stranded along with the core 120B in Figure 10. The rip cord 140 may be constructed of polyester, aramid fibers, like KELVAR, or even a stranded metal wire.

[0080] Figure 11 is an end view of a flat drop cable HOC, in accordance with a second alternative embodiment of the present invention. The flat drop cable HOC includes larger components and / or dimensions, which may permit the flat drop cable 110C to be used in a long- span aerial deployment, e.g., exceeding two hundred feet. One difference between the flat drop cable HOC in Figure 11 and the flat drop cable 110B in Figure 10 is that the first and second reinforcing members 122C and 124C are each formed as a glass reinforced plastic (GRP) rod with a larger diameter of 2.6 mm, instead of 2.3 mm.

[0081] Another difference is that the core 120C includes exactly four buffer tubes, i.e., first, second, third and fourth buffer tubes 130C, 132C, 134C and 135C are embedded within the jacket 114C. It is noted that the four buffer tubes 130CB, 132C, 134C and 135C are not linearly aligned with each other between the first and second reinforcing members 122C and 124C. Rather, the four buffer tubes 130CB, 132C, 134C and 135C are stranded together to form the core 120C. The four buffer tubes 130CB, 132C, 134C and 135C are preferably helically stranded together and require no binders. However, the four buffer tubes 130CB, 132C, 134C and 135C may alternatively be SZ stranded together, in which case one or two binder threads or tapes may encircle the core 120C to hold the core 120C together during manufacturing of the flat drop cable HOC.

[0082] Each of the first, second, third and fourth buffer tubes 130C, 132C, 134C and 135C includes a plurality of optical fibers 128, such as at least eight optical fibers 128. In the embodiment depicted in Figure 11, each of the first, second, third and fourth buffer tubes 130C, 132C, 134C and 135C includes at least twelve optical fibers 128. However, each of the first, second, third and fourth buffer tubes 130C, 132C, 134C and 135C may include more or fewer optical fibers 128, such as six or sixteen optical fibers 128.

[0083] A diameter of each of the first, second, third and fourth buffer tubes 130C, 132C, 134C and 135C is about 1.5 mm plus or minus ten percent, more preferably plus or minus three percent. This results in an overall core diameter of 3.5 mm plus or minus ten percent, most preferably about 3.5 mm. As shown in Figure 11, the central longitudinal axis 12 does not pass through any of the four buffer tubes, however this is not essential to the invention. The stranding of the four buffer tubes 130C, 132C, 134C and 135C prior to having the jacket 114C extruded thereon would look like Figure 8, except that four elements are helically stranded instead of three elements. A lay or strand length S of the core 120C is greater than 12 inches, such as about 20 to 50 inches. In a preferred embodiment, the strand length S of the core 120C is about 25 to 40 inches, e.g., about 30 to 36 inches.

[0084] In a preferred embodiment of the flat drop cable 110C, each of the four buffer tubes 130C, 132C, 134C and 135C is extruded from a colored material, which distinguishes it from the other three buffer tubes. Alternatively, each of the four buffer tubes DOC, 132C, 134C and 135C may include a color stripe, e.g., blue, green, red or yellow, which distinguishes it from the other three buffer tubes.

[0085] Another difference between the flat drop cable 110C of Figure 11 and the flat drop cable HOB of Figure 10 is an outer surface profile of the jacket 114C and a larger overall size of the flat drop cable 1 10C. The jacket 114C of the flat drop cable 110C extends along the central longitudinal axis 12 and has a transverse cross-sectional profile (shown in Figure 11) which is elongated such that the width W4 is larger than the thickness T2. The jacket 114C of the flat drop cable HOC includes opposite top and bottom sides 326, 326A which have a radius of curvature, and that extend between opposite rounded ends 327, 327A, which have a smaller radius of curvature as compared to the top and bottom sides 327 and 327A.

[0086] The radius of curvature of the top and bottom sides 326, 326A of the flat drop cable 110C is greater than the radius of curvature of the top and bottom sides 226, 226A of the flat drop cable HOB, i.e., the top and bottom sides 326, 326A appear more flat. Also, the radius of curvature of the opposite rounded ends 327, 327A of the flat drop cable 1 IOC is greater than the radius of curvature of the opposite rounded ends 227, 227A of the flat drop cable HOB, i.e., the rounded ends 327, 327A appear more flat. The thickness T2 of the flat drop cable 1 IOC extends between the top and bottom sides 326, 326A, while the width W4 of the flat drop cable HOC extends between the rounded ends 327, 327A.

[0087] The width W4 is 10.1 mm plus or minus ten percent, such as between 9.9 to 11.1 mm. In a preferred embodiment, the width W4 is about 10.1 mm, so that the drop cable 110C is compatible with the larger and stronger clamp 32 of Figure 3, which has a shell 33 with a width X of about 16 mm. The thickness T2 is 4.9 mm plus or minus about ten percent. In a preferred embodiment, the thickness T2 is about 4.9 mm, so that the flat drop cable 110C is compatible with the clamp 32 of Figure 3.

[0088] The other symmetries of the flat drop cable HOB relative to the minor and major axes 16 and 18 may apply to the flat drop cable 110C. Also, the flat drop cable 110C may include one or more water blocking tapes or threads 136 and one or more rip cords 140 within the interstices 138 between the four buffer tubes 130C, 132C, 134C and 135C.

[0089] Figure 12 is an end view of a flat drop cable HOD, in accordance with a third alternative embodiment of the present invention. The flat drop cable HOD includes larger components and / or dimensions, which may permit the flat drop cable 110D to be used in a long- span aerial deployment, e.g., exceeding two hundred feet. One difference between the flat drop cable HOD in Figure 12 and the flat drop cable HOB in Figure 10 is that the first and second reinforcing members 122D and 124D are each formed as a glass reinforced plastic (GRP) rod with a larger diameter of 2.75 mm, instead of 2.3 mm.

[0090] The three buffer tubes BOD, 132D and 134D have a slightly smaller diameter at 1.45 mm, instead of 1.5 mm. This results in a core 120D having an overall core diameter of 3.0 mm. As described above regarding the flat drop cable 110, the three buffer tubes BOD, 132D and 134D are preferably distinguished by different colors and preferably helically stranded togetherand require no binders. The stranding of the three buffer tubes 130D, 132D and 134D prior to having the jacket 114D extruded thereon would look like Figure 8. A lay or strand length S of the core 120D is greater than 12 inches, such as about 20 to 50 inches. In a preferred embodiment, the strand length S of the core 120D is about 25 to 40 inches, e.g., about 28 to 32 inches.

[0091] Another difference between the flat drop cable HOD of Figure 12 and the flat drop cable HOB of Figure 10 is an outer surface profde of the jacket 114D and a larger overall size of the flat drop cable HOD. The jacket 114D of the flat drop cable HOD extends along the central longitudinal axis 12 and has a transverse cross-sectional profde (shown in Figure 12) which is elongated such that the width W5 is larger than the thickness T3. The jacket 114D of the flat drop cable HOD includes opposite top and bottom sides 426, 426 A which have a radius of curvature, and that extend between opposite rounded ends 427, 427A, which have a smaller radius of curvature as compared to the top and bottom sides 427 and 427A.

[0092] The radius of curvature of the top and bottom sides 426, 426A of the flat drop cable 110D is greater than the radius of curvature of the top and bottom sides 226, 226A of the flat drop cable HOB, i.e., the top and bottom sides 426, 426A appear more flat. Also, the radius of curvature of the opposite rounded ends 427, 427A of the flat drop cable HOD is greater than the radius of curvature of the opposite rounded ends 427, 427A of the flat drop cable HOB, i.e., the rounded ends 427, 427A appear more flat. The thickness T3 of the flat drop cable 110D extends between the top and bottom sides 326, 326A, while the width W4 of the flat drop cable HOD extends between the rounded ends 427, 427A.

[0093] The width W5 is 10.0 mm plus or minus ten percent, such as between 9 to 11 mm. In a preferred embodiment, the width W5 is about 10.0 mm, so that the flat drop cable HOD is compatible with the larger and stronger clamp 32 of Figure 3, which has a shell 33 with a width X of about 16 mm. The thickness T3 is 4.5 mm plus or minus about ten percent. In a preferred embodiment, the thickness T3 is about 4.5 mm, so that the flat drop cable 110D is compatible with the clamp 32 of Figure 3.

[0094] The other symmetries of the flat drop cable HOB relative to the minor and major axes 16 and 18 may apply to the flat drop cable 110D. Also, the flat drop cable HOD may includeone or more water blocking tapes or threads 136 and one or more rip cords 140 within the interstices 138 between the three buffer tubes BOD, 132D and 134D.

[0095] Figure 13 is an end view of the flat drop cable 110 of Figure 7 upjacketed to first and second micro-ducts 152 and 154 to form an optical communications cable 151. The first and second micro-ducts 152 and 154 are empty extruded polymer conduits, which allow for easy expansion of the channel capacity of the optical communications cable 151 after its installation. One or more optical and / or electrical cables may be fish-taped or blown through the first and second micro-ducts 152 and 154 to add additional communication channels and / or power supply channels to the installed optical communications cable 151.

[0096] The first and second micro-ducts 152 and 154 in Figure 10 have an outer diameter of greater than 5 mm, such as 8 mm or 10 mm. The flat drop cable 110 resides between the first and second empty micro-ducts 152 and 154. An over jacket 156 surrounds the flat drop cable 110 and the first and second micro-ducts 152 and 154. The over jacket 156 may be formed of an extruded polymer, like Polyethylene (PE), or any other material used in the cabling art.

[0097] Figure 14 is an end view of the flat drop cable 110 of Figure 7 upjacketed to first, second, third and fourth micro-ducts 158, 160, 162 and 164 to form an optical communications cable 157. The first, second, third and fourth micro-ducts 158, 160, 162 and 164 are empty extruded polymer conduits, which allow for easy expansion of the channel capacity of the optical communications cable 157 after its installation. One or more optical and / or electrical cables may be fish-taped or blown through the first, second, third and fourth micro-ducts 158, 160, 162 and 164 to add additional communication channels and / or power supply channels to the installed optical communications cable 157.

[0098] The first, second, third and fourth micro-ducts 158, 160, 162 and 164 in Figure 11 have an outer diameter of greater than 5 mm, such as 8 mm or 10 mm. The flat drop cable 1 10 resides between the first and third empty micro-ducts 158 and 162 on one side of said flat drop cable 110, and between the second and fourth empty micro-ducts 160 and 164 on an opposite side of the flat drop cable 110. An over jacket 166 surrounds the flat drop cable 110 and the first, second, third and fourth micro-ducts 158, 160, 162 and 164. The over jacket 166 may be formed of an extruded polymer, like Polyethylene (PE), or any other material used in the cabling art.

[0099] Figure 15 is an end view of the flat drop cable 110 of Figure 7 upjacketed to first, second, third, fourth, fifth and sixth micro-ducts 168, 170, 172, 174, 176 and 178 to form an optical communications cable 167. The first, second, third, fourth, fifth and sixth micro-ducts 168, 170, 172, 174, 176 and 178 are empty extruded polymer conduits, which allow for easy expansion of the channel capacity of the optical communications cable 167 after its installation. One or more optical and / or electrical cables may be fish-taped or blown through the first, second, third, fourth, fifth and sixth micro-ducts 168, 170, 172, 174, 176 and 178 to add additional communication channels and / or power supply channels to the installed optical communications cable 167.

[0100] The first, second, third and fourth micro-ducts 168, 170, 172 and 174 in Figure 12 have a first outer diameter of greater than 5 mm, such as 8 mm or 10 mm. The fifth and sixth micro-ducts 176 and 178 have a smaller, second outer diameter of 5mm of less, such as 5 mm or 3.5 mm. The flat drop cable 110 resides between the first and third empty micro-ducts 168 and 172 on one side of said flat drop cable 110, and between the second and fourth empty micro-ducts 170 and 174 on an opposite side of the flat drop cable 110. The flat drop cable 110 also resides between the fifth empty micro-duct 176 on one side of said flat drop cable 110 and the sixth empty micro-duct 178 on an opposite side of the flat drop cable 110. An over jacket 176 surrounds the flat drop cable 110 and the first, second, third, fourth, fifth and sixth micro-ducts 168, 170, 172, 174, 176 and 178. The over jacket 176 may be formed of an extruded polymer, like Polyethylene (PE), or any other material used in the cabling art.

[0101] Although Figures 13-15 show the flat drop cable 110 of Figure 7 upjacketed to micro-ducts, the flat drop cables HOB, HOC and HOD of Figures 10-12 could replace the flat drop cable 110 in Figures 13-15.

[0102] In certain examples, strength members, such as numerous aramid yarns like KELVAR, can be provided in the core 120, 120B, 120C, 102D and / or surrounding the core 120, 120B, 120C, 120D. In certain examples, the strength members 34 can include a superabsorbent polymer (SAP) powder or added threads that swell when exposed to water so as to inhibit the intrusion of water along the core 120, 120B, 120C, 120D. The strength members, such as aramid yams or polyester yarns, can add mechanical reinforcement to the flat drop cable duringinstallation and thereafter. The strength members can also assist in attaching a connector to the cable when the cable is terminated.

[0103] The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.

Claims

We claim:

1. A flat drop cable comprising: a jacket having a length that extends along a central longitudinal axis of said fiber optic cable, said jacket defining a transverse cross-sectional profile having a thickness and a width, the thickness being smaller than the width, the transverse cross-sectional profile of said jacket defining a major axis that extends across the width of said jacket and a minor axis that extends across the thickness of said jacket, the major and minor axes being perpendicular to one another and also being perpendicular to the central longitudinal axis of said fiber optic cable, and the major axis and the minor axis intersecting each other at the central longitudinal axis; and first, second and third buffer tubes positioned within the jacket, each of said first, second and third buffer tubes including at least eight optical fibers, wherein said first, second and third buffer tubes are stranded together to form a core that extends along the central longitudinal axis.

2. The flat drop cable of claim 1, wherein said jacket defines first and second flat sides separated by the thickness and first and second rounded ends separated by the width.

3. The flat drop cable of claim 1, wherein each of said first, second and third buffer tubes includes at least twelve optical fibers.

4. The flat drop cable of claim 1, wherein the central longitudinal axis does not pass through any of said first, second and third buffer tubes.

5. The flat drop cable of claim 1 , wherein said first, second and third buffer tubes are helically stranded together.

6. The flat drop cable of claim 1, wherein said first, second and third buffer tubes are SZ stranded together.

7. The flat drop cable of claim 1, wherein said jacket defines first and second curved sides separated by the thickness and first and second rounded ends separated by the width, and wherein said first and second curved sides have a greater radius of curvature as compared to said first and second rounded ends.

8. The flat drop cable of claim 1, further comprising: a fourth buffer tube positioned within the jacket, said fourth buffer tube including at least eight optical fibers, wherein said first, second, third and fourth buffer tubes are stranded together to form a core that extends along the central longitudinal axis.

9. The flat drop cable of claim 8, wherein each of said first, second, third and fourth buffer tubes includes at least twelve optical fibers.

10. The flat drop cable of claim 8, wherein the central longitudinal axis does not pass through any of said first, second, third and fourth buffer tubes.

11. The flat drop cable of claim 8, wherein said first, second, third and fourth buffer tubes are helically stranded together.

12. The flat drop cable of claim 8, wherein said first, second, third and fourth buffer tubes are SZ stranded together.

13. The flat drop cable of claim 8, wherein said jacket defines first and second curved sides separated by the thickness and first and second rounded ends separated by the width, and wherein said first and second curved sides have a greater radius of curvature as compared to said first and second rounded ends.

14. A flat drop cable comprising:a jacket having a length that extends along a central longitudinal axis of said fiber optic cable, said jacket defining a transverse cross-sectional profile having a thickness and a width, the thickness being smaller than the width, the transverse cross-sectional profile of said jacket defining a major axis that extends across the width of said jacket and a minor axis that extends across the thickness of said jacket, the major and minor axes being perpendicular to one another and also being perpendicular to the central longitudinal axis of said fiber optic cable, and the major axis and the minor axis intersecting each other at the central longitudinal axis; first and second reinforcing members embedded within said jacket; and exactly three buffer tubes embedded within said jacket, each of said three buffer tubes including a plurality of optical fibers, wherein said three buffer tubes are not linearly aligned with each other between said first and second reinforcing members.

15. The flat drop cable of claim 14, wherein said first and second reinforcing members are each formed as a glass reinforced plastic (GRP) rod.

16. The flat drop cable of claim 14, wherein said three buffer tubes are stranded together to form a core that extends along the central longitudinal axis.

17. The flat drop cable of claim 16, wherein said core has a diameter of 3 to 3.1 mm plus or minus three percent.

18. The flat drop cable of claim 16, wherein a lay length of said core is greater than 12 inches.

19. The flat drop cable of claim 18, wherein the lay length of said core is 20 to 50 inches.

20. The flat drop cable of claim 19, wherein the lay length of said core is 25 to 35 inches.

21. The flat drop cable of claim 14, wherein the width is 7.9 mm plus or minus ten percent.

22. The flat drop cable of claim 21, wherein the width is 7.9 mm plus or minus three percent.

23. The flat drop cable of claim 14, wherein the thickness is 4.5 mm plus or minus about ten percent.

24. The flat drop cable of claim 23, wherein the thickness is 4.5 mm plus or minus three percent.

25. The flat drop cable of claim 14, wherein the width is 10 mm plus or minus ten percent.

26. The flat drop cable of claim 25, wherein the width is 9.4 mm or 10.0 mm plus or minus three percent.

27. The flat drop cable of claim 14, further comprising: at least one water-blocking tape or thread abutting said core.

28. The flat drop cable of claim 14, further comprising: at least one rip cord abutting said core.

29. The flat drop cable of claim 14, wherein each of said three buffer tubes is extruded from a colored material, which distinguishes it from the other two buffer tubes.

30. The flat drop cable of claim 14, wherein each of said three buffer tubes includes a color stripe, which distinguishes it from the other two buffer tubes.

31. An optical communications cable comprising: an extruded over jacket surrounding: a flat drop cable constructed in accordance with one of claims 1-30; and at least one empty micro-duct.

32. The optical communications cable of claim 31, wherein said at least one empty microduct includes first and second empty micro-ducts and said flat drop cable resides between said first and second empty micro-ducts.

33. The optical communications cable of claim 31, wherein said at least one empty microduct includes first, second, third and fourth empty micro-ducts and said flat drop cable resides between said first and third empty micro-ducts on one side of said flat drop cable and said second and fourth empty micro-ducts on an opposite side of said flat drop cable.

34. The optical communications cable of claim 31, wherein said at least one empty microduct includes a first micro-duct having a first diameter and a fifth micro-duct having a second diameter which is less than said first diameter.

35. The optical communications cable of claim 34, wherein said at least one empty microduct further includes second, third and fourth micro-duct having the first diameter and a sixth micro-duct having the second diameter, and wherein said flat drop cable resides between said first and third empty micro-ducts on one side of said flat drop cable and said second and fourth empty micro-ducts on an opposite side of said flat drop cable.

36. The optical communications cable of claim 35, wherein said flat drop cable resides between said fifth empty micro-duct on one side of said flat drop cable and said sixth empty micro-duct on an opposite side of said flat drop cable.

Images