This disclosure generally pertains to cable routing, and more particularly to a cable slack management apparatus.
In fiber optic networks, fiber optic cables may be connected to various fiber optic assemblies (e.g., hardware, housings, enclosures, etc.). The fiber optic cables may include slack in addition to the cabling needed to make optical connections. This slack may enable the cable to be routed in the fiber optic assembly and/or enable removal of a portion of the cable from the fiber optic assembly, such as to facilitate optical connections, e.g. splicing and patching. Additionally, the slack may be used to facilitate repairs or reconfigurations in which a portion of the cable may be discarded. The slack may be stored inside the fiber optic assembly in one or more cable management solutions.
Various solutions for cable management and overlength management are available on the market. In most cases, a tray approach is used, which can be arranged and stacked inside the device. Routing functionalities and overlength-management may be realized by manual winding of single fibers around fixed integrated support structure. In some co-packaged optical solutions including high density small form factor switch deployments, cable management is performed by a “fiber shuffle”, however these fiber shuffles are highly sophisticated and specific to the switch design resulting in a high volume price and limiting serviceability. One fiber shuffle may connect to multiple input and output connections including multiple active alignment coupling processes. If a coupling fails, the entire fiber shuffle may require replacement.
To optimally arrange and service cable assemblies within a data center switch requires custom assembly lengths manufactured to +/1 mm tolerances. However, these length tolerances would be extremely difficult and costly to implement within current manufacturing processes and the number of specific lengths needed to make up the switch is significant. Due to the length variation of the incoming cable assemblies, it is desired to incorporate an excess amount of length within a set number of assembly lengths and then efficiently manage the excess length within the switch.
Additional features and advantages will be set forth in the detailed description which follows, and in part will be apparent to those skilled in the art from the description or recognized by practicing the embodiments as described in the written description and claims hereof, as well as the appended drawings.
It is to be understood that both the foregoing general description and the following detailed description are merely exemplary, and are intended to provide an overview or framework to understand the nature and character of the claims.
The accompanying drawings are included to provide a further understanding, and are incorporated in and constitute a part of this specification. The drawings are illustrative of selected aspects of the present description, and together with the specification explain principles and operation of methods, products, and compositions embraced by the present description. Features shown in the drawing are illustrative of selected embodiments of the present description and are not necessarily depicted in proper scale.
While the specification concludes with claims particularly pointing out and distinctly claiming the subject matter of the written description, it is believed that the specification will be better understood from the following written description when taken in conjunction with the accompanying drawings, wherein:
The embodiments set forth in the drawings are illustrative in nature and not intended to be limiting of the scope of the detailed description or claims. Whenever possible, the same reference numeral will be used throughout the drawings to refer to the same or like features. The drawings are not necessarily to scale for ease of illustration an explanation.
Optical fibers are useful in a wide variety of applications, including the telecommunications industry for voice, video, and data transmissions. The benefits of optical fiber are well known and include higher signal-to-noise ratios and increased bandwidth compared to conventional copper-based transmission technologies. To meet modern demands for increased bandwidth and improved performance, telecommunication networks are increasingly providing optical fiber connectivity closer to end subscribers. These initiatives include fiber-to-the-node (FTTN), fiber-to-the-premises (FTTP), fiber-to-the-home (FTTH), and the like (generally described as FTTx).
In an FTTx network, fiber optic cables are used to carry optical signals to various distribution points and, in some cases, all the way to end subscribers. For example,
At network access points closer to the subscriber premises 14, some or all of the optical fibers in the distribution cables 20 may be accessed to connect to one or more subscriber premises 14. Drop cables 22 extend from the network access points to the subscriber premises 14, which may be single-dwelling units (SDU), multi-dwelling units (MDU), businesses, and/or other facilities or buildings. A SDU or MDU terminal may be disposed at the subscriber premises 14. A conversion of optical signals back to electrical signals may occur at the network access points or at the subscriber premises 14.
There are many different network architectures, and the various tasks required to distribute optical signals (e.g., splitting, splicing, routing, connecting subscribers) can occur at several locations. Regardless of whether a location is considered a switching point, local convergence point, network access point, subscriber premise, or something else, fiber optic equipment is used to house components that carry out one or more of the tasks. The fiber optic equipment may be assemblies that include connectors, switches, splitters, splices, or the like. The term “fiber optic assembly” will be used in this disclosure to generically refer to such equipment (or at least portions thereof). In some instances, such equipment is located at a switching point 12 in an FTTx network, although this disclosure is not limited to any particular intended use. Further, although an FTTx network 10 is shown in
With increasing needs for higher bandwidth in telecommunication or industrial applications, the number of optical inputs and outputs (I/O) rises drastically. A high I/O count has a resulting increase in optical fiber count inside opto-electronical devices, such as switching points 12. Organization and management of single fibers up to high-density optical cable bundles becomes increasingly necessary as the optical fiber count increases. Fiber routing may be applied to ensure traceable, serviceable, and organized fiber management from optical input to the electronic device observing minimum bend radii. Cable overlength/surplus management may also be utilized because individual I/O routing trace-lengths vary from position to position and cable lengths may be mismatched. Managing high fiber count bundles, for example 92 fibers or 144 fibers, introduces additional challenges because the required fiber bending force is higher compared to individual fibers. Furthermore, optical fibers have a strong spring back tendency and try to straighten if possible, which makes a loose fiber routing difficult.
In current data-center switches (e.g., switches with 12.8 Tbps bandwidth), external fiber-optic connections are generally terminated in pluggable transceivers at the faceplate of the housing. Optical fiber is not generally present within the switch housing where signals are transported electrically via, e.g., copper traces on printed circuit boards. With increasing data rates, these electrical connections are becoming more lossy and progressively distort the transmitted signals. Overcoming electrical loss requires electrical power which is projected to strongly increase for the coming generations of higher-bandwidth switches due to higher data rates and higher numbers of data channels. Such an increase of power consumption poses several problems regarding operational cost, electric power infrastructure, and waste heat management. Going forward, to reduce power consumption, the industry moving toward placement of the transceivers inside the switch housing very close to where the signals are generated: the switch application-specific integrated circuit (ASIC). This effectively replaces long runs of electrical connections with optical-fiber connections, which are virtually loss free for the for the lengths described herein, thus reducing the required signal power. Replacement of the electrical connections with fiber optic connections may necessitate routing of optical fibers within the switch housing. The fiber count can be very high (hundreds to thousands of fibers), and the available space may be very limited driven by many coexisting non-fiber switch components as well as expectations for compact housing sizes. Therefore, the fiber density is expected to be very high within the switch housing.
Details of the fiber routing will strongly impact the case of assembly and serviceability in case of failure of individual switch components. In particular, a crossing-free layout of fiber runs which connect the different transceivers to the faceplate would make the replacement of an individual transceiver with permanently attached fibers far easier as all other fiber runs could remain untouched. Such an orderly routing of many fibers required a tight control of fiber-cable lengths which may be costly to achieve given the length variation in manufacturing.
The constraint placed on the cable assembly lengths will have direct effect on the number of assembly crossovers and will thus affect the ability for an assembly technician to efficiently arrange the cable assemblies and rework/replace defective assemblies. An idealized cable routing scheme would have a multitude of cable assembly lengths that are tailored to a specific route within the switch. Tailoring the length for each cable path results in no cable crossovers and thus will facilitate easier assembly of the switch. This tailored arrangement also allows for easier removal and replacement of “faulty” assemblies that are detected during production quality testing of the switch. However, the ability to create these specific lengths is challenging in current optical fiber cable assembly manufacturing. Some of the manufacturing challenges include management of the groups of cable assembly lengths need thus resulting in stock keeping unit (SKU) proliferation; length variation within groups of cable assembly lengths resulting in crossovers; and rework of cable assemblies may result in a 50 mm reduction in the length of the cable assembly. Significant scrap costs would result without the appropriate management of target lengths for reworked product.
The switch housing 100 includes an adapter panel 106 configured to receive one or more fiber optic adapters 108. The fiber optic adapters 108 may be configured to receive a connector such as multi-fiber push-on/pull-off (MPO) connectors (e.g., according to IEC 61754-7). In some examples, the multi-fiber fiber optic components may include very-small form factor (VSFF) connectors or adapters, such as MDC connectors or adapters (sometimes referred to as “mini duplex connectors”) offered by U.S. Conec, Ltd. (Hickory, NC), and SN connectors or adapters (sometimes referred to as a Senko Next-generation connectors) offered by Senko Advanced Components, Inc. (Marlborough, MA). Such VSFF connectors or adapters may be particularly useful in the structured optical fiber cable systems in this disclosure, and may be referred to generically as “dual-ferrule VSFF components” due to their common design characteristic of the connectors having two single-fiber ferrules within a common housing (and the adapters being configured to accept such connectors).
At least one cable 110, also referred to as a “cable assembly”, may be provided optically connecting the one or more fiber optic adapters 108 to the opto-electronic device 104. Introduction of length variations in the cables fiber optic cables on the order of +/−5 mm results in the crossing of cable assemblies which is undesirable. Due to the manufacturing challenges and tight tolerances for variation, “idealized” routing schemes may be cost prohibitive. From a manufacturing perspective several goals emerge: a minimum number of SKUs; allowable length variation within the cable assembly SKUs of greater than +/−5 mm; method to shorten/tailor the length of the cable assembly SKUs after the installation of the Fiber Array Unit (FAU) and the MPO connector; and an efficient arrangement within the switch by minimizing the amount of occupied space within the switch.
Given the orientation of the opto-electronic device 104 to the adapter panel 106, there are two primary paths for the fiber optic cables 110 on each side of the switch housing 100 when using a symmetrical cable routing scheme. One of the primary paths will be the group of fiber optic cables 110 originating at the adapter panel 106 and terminate at the far side of the opto-electronic device 104 and the other primary path will be the group of fiber optic cables 110 that originate at the adapter panel 106 and terminate at the near side of the opto-electronic device 104.
The cable assembly lengths for the near and far side groups of fiber optic cables 110 for an example opto-electronic device 104, e.g. a 256f switch, include a first range of the near side lengths of 219-221 mm (2 mm difference) and a second range of the far side lengths is 447-516 mm (69 mm difference). A larger opto-electronic device 104, such as a switch containing 1024f configuration may include cable assembly lengths for the near and far side groups of fiber optic cables 110 having a first range of the near side lengths is 218-222 mm (4 mm difference) and the second range of the far side lengths is 435-516 mm (81 mm difference).
If an ideal cable routing scheme with an allowable length variation of +/−1 mm following number of SKUs for each of the above switches:
In order to maximize efficiencies within the cable assembly manufacturing process, it is desired to minimize the number of cable assembly SKUs. It is also desired to salvage/rework any cable assemblies that fail any in process QC checks. Reworked cable assemblies are assumed to consume 50 mm of the original cable assembly length.
In an example embodiment a cable manager may be provided, as disclosed herein to 1) ensure proper cable routing within the switch with a cable assembly length accuracy of +/−1 mm, 2) ensure the ability to gain access to individual cable assemblies withing the switch; 3) minimize cable assembly SKUs to maximize cable assembly manufacturing efficiency, and/or 4) accommodate reworked (shortened) cable assemblies require that a longer than required cable assembly be manufactured and its length subsequently adjusted (i.e. shortened) to within +/−1 mm for the particular cable route required. It is proposed that an apparatus to accumulate excess length of the cable assembly be incorporated as part of the cable assembly and that this adjustment function be performed within a post cable assembly process step.
The accumulation, within a cable manager 120, of length of the fiber optic cable 110 within a post cable assembly process step may enable length tolerances of +/−1 mm and thus enable accurate placement of the cable assemblies within the switch housing 100. A length tolerance of +/−1 mm for the fiber optic cable 110 will ensure no cable assembly crossovers and thus reduce complexity of assembly of the cable assemblies within the switch housing 100 and also allow for any cable assembly that is “flagged” during switch testing to be easily accessed and replaced if necessary.
The trimming/adjustment of cable assembly length within a post cable assembly process may allow for a larger cable assembly length tolerance than that required for the length tolerance for a specific cable route. For example, an allowable length tolerance of +/−5 mm of a fiber optic cable 110 may be acceptable in the cable assembly process given that the subsequent accumulation trough process can adjust the length to within +/−1 mm.
The post adjustment of length will also enable a reduction in the number of cable assembly SKUs required and reduce the number of scraped cable assembly SKUs that cannot be reworked. For example, it is anticipated that the total number of SKUs for the 256f switch and the 1024f switch can be reduced from 5 to 2 and 18 to 2, respectively. Both the SKU reduction and the reduction in possible scrap will have a significant effect on reducing the cost of the finished switch.
To adjust the length of a fiber optic cable 110 within a post cable assembly process, the length of the fiber optic cable 110 must be longer than that of the target length. In an example case, the fiber optic cable 110 may have a length variation of +/−5 mm. An additional assumption provides that reworked cable assemblies will be 50 mm shorter than the original length and have an inherent length variation, e.g. +/−5 mm. In this example, there are two groups of fiber optic cables 110 for each of the near and far side of the cable routes, relative to the opto-electronic device 104. One group of fiber optic cables 110 may be the first pass cable assemblies and the other group of fiber optic cables 110 may be reworked cable assemblies. For each of the cable assemblies to be used for any of the respective near side or far side routes, the shortest cable assembly length may be adjusted for the longest cable route while the longest cable assembly length may be adjusted to the shortest cable route. The length to be accumulated for the near and far side cable assemblies depends on the following parameters: 1) cable assembly length variation, e.g. +/−5 mm in the present example; 2) cable route length variation; 3 minimum cable assembly length for the cable manager 120, e.g. the cable length at a maximum extension from the cable manager 120, here 50 mm; and 4) the length of fiber optic cable 110, assumed to be 50 mm.
An example calculation of the target cable assembly length and the accumulated fiber optic cable 110 for the near and far side routes are provided below.
Returning to
The cable manager 120 may also include one or more mandrels 129 extending from the base 123 and internal to the sidewall 124. The mandrels 129 in cooperation with sidewall 124 are configured to enable bending of the fiber optic cable to greater than a predetermined minimum bend radius, such as 5 mm, 8 mm, 10 mm, 12 mm, or other suitable bend radius. The mandrels 129 may also define one or more cable routing paths within the cable manager 120b. In the mandrels 129 may enable a slack loop 122 to be routed inside the cable manager 120b without utilization of adhesives, which may make reworking of the fiber optic cable 110 easier and faster.
In some example embodiment, the fiber optic cable 110 may include a rollable ribbon or intermittently boded ribbon disposed within a cable jacket. Ribbon(s) may be conventionally coated, substantially coated, or continuously coated. In an example embodiment, a portion of the cable jacket may be removed to from an unjacketed portion 111. The unjacketed portion 111 may be “unrolled” into a planer rollable ribbon, which may provide a smaller minimum bend radius. The unjacketed portion 111 may be routed within the cable manager 120b including the slack loop 122, thus enabling a smaller footprint that would be otherwise possible with the jacketed and/or bunched rollable ribbon.
Turning to
In an example embodiment, the cable manager 120b may have a length of 20-200 mm; a height of 15-25 mm; and a width of 2-10 mm. The cable manager 120b may include 2, 3, or any suitable number of mandrels to control a path of the fiber optic cable 110 and an internal bend radius of 5-10 mm, 10-15 mm, 15-25 mm, or other suitable bend radii for the fiber optic cable 110. The cable manager 120b may be horizontally stacked, such as depicted in
In some embodiments, the fiber optic cable 110 within the switch housing 100 may be unjacketed. In an example embodiment, the fiber optic cable 110 within the switch housing 100 may be pre-shaped to aid in switch assembly/cable routing. The pre-shaping of the fiber optic cable 110 may also aide in reducing the need for stress relief at the cable FAU/connector ends.
Turning to
In some example embodiments, the cable manager 120c may include one or more cable accumulation troughs 132 disposed along the cable routing channels, as shown in
In the depicted embodiment, the near side group of cable accumulation troughs 132 are radial accumulation troughs 132a. The radial accumulation troughs 132a, shown in further detail in
The far side group of cable accumulation troughs 132 are linear accumulation troughs 132b. The linear accumulation troughs 132b, shown in further detail in
In some embodiments, the fiber optic cable 110 may overlap another portion of the fiber optic cable 110 in the cable accumulation trough 132. The overlap may maximize the bend radius and eliminate cable twist, with a negligible increase in height of the base 130.
In an example embodiment, the fiber optic cable 110 may be retained in the cable accumulation trough 132 by friction caused by spring back pressure of the fiber optic cable 110 against the sidewall of the cable accumulation trough 132. In an example embodiment, an adhesive may be used to retain the fiber optic cable 110 within the cable accumulation trough 132. In some embodiments, the cable accumulation trough 132 may include a lip or flange extending inward from base 130 at an upper edge of the cable accumulation trough 132. The lip or flange may resist movement of the fiber optic cable 110 out of the cable accumulation trough 132.
In some example embodiments, the switch housing 100 may include one or more lasers 134, as depicted in
In an example embodiment, a fiber optic assembly is provided including a housing base configured to support one or more fiber optic communication connections, a housing sidewall extending from the housing base, an opto-electrical device supported by the housing base, an adapter panel supporting one or more fiber optic adapters, at least one optical fiber optically connecting the one or more fiber optic adapters to the opto-electronic device, and at least one cable manager supported on the housing base and routing at least a portion of the at least one optical fiber from the one or more fiber optic adapters to the opto-electronic device. The at least cable manager includes a base, a sidewall extending from the base and defining an input opening and an output opening, and a plurality of mandrels extending from the base and interior to the sidewall. The plurality of mandrels and the sidewall are configured to limit bending of the at least one optical fiber to greater than a predetermined bend radius.
In some example embodiments, the at least one optical fiber comprises a plurality of optical fiber ribbons each configured as a rollable ribbon. In an example embodiment, at least a portion of each of the optical fiber ribbons that is disposed within the at least one cable manager is not surrounded by a cable jacket. In some example embodiments, the fiber optic assembly also includes at least one cable that includes the plurality of optical fiber ribbons, where the at least one cable comprises a jacketed portion retained in the input opening or the output opening. In an example embodiment, the plurality of optical fibers have a planar configuration in the at least one cable manager. In some example embodiments, the sidewall further defines a plurality of output openings. In an example embodiment, the plurality of output openings comprise a first output opening disposed at a first end of the at least one cable manager proximate to the input opening and a second output opening disposed at a second end of the at least one cable manager opposite the input opening. In some example embodiments, the plurality of output openings further includes a third output opening disposed in the sidewall between the first end and the second end of the at least one cable manager. In an example embodiment, the at least one cable manger includes a plurality of cable mangers disposed in a horizontal stack. In some example embodiments, the at least one cable manager includes a plurality of cable managers disposed in a vertical orientation extending from the housing base.
In another example embodiment, a fiber optic cable manager is provided configured to receive at least one optical fiber optically connecting one or more fiber optic adapters to a fiber optic device. The fiber optic cable manager includes a base, a sidewall extending from the base and defining a cable input opening and a cable output opening, at least one cable optically connecting one or more fiber optic adapters to an opto-electronic device, and a plurality of mandrels extending from the base and interior to the sidewall, the plurality of mandrels and the sidewall are configured to limit bending of the at least one optical to greater than a predetermined bend radius.
In some example embodiments, the sidewall further defines a plurality of output openings. In an example embodiment, the plurality of output openings includes a first output opening disposed at a first end of the cable manager proximate to an input opening and a second output opening disposed at a second end of the cable manager opposite the input opening. In some example embodiments, the plurality of output openings further includes a third output opening disposed in the sidewall between the first end and the second end.
In yet a further example embodiment, a fiber optic assembly is provided including a housing base configured to support one or more fiber optic communication connections, a housing sidewall extending from the housing base, an opto-electrical device supported by the housing base, an adapter panel configured to receive one or more fiber optic adapters, at least one optical fiber optically connecting the one or more fiber optic adapters to an opto-electronic device, and at least one cable manager supported on the housing base. The at least one cable manager includes a base, a plurality of cable routing channels disposed in the base, and at least one cable accumulation trough disposed along at least one of the plurality of cable routing channels. The at least one cable accumulation trough is configured to limit bending of the at least one optical fiber to greater than a predetermined bend radius.
In some example embodiments, the base comprises a removable plate and the plurality of cable routing channels or the at least one cable accumulation trough is disposed on the removable plate. In an example embodiment, the at least one cable accumulation trough comprises a plurality of cable accumulation troughs. In some example embodiments, at least a some of the plurality of cable accumulation troughs include linear accumulation troughs. In an example embodiment, at least a some of the plurality of cable accumulation troughs comprise radial accumulation troughs.
In yet another example embodiment, a fiber optic assembly is provided including a housing base configured to support one or more fiber optic communication connections, a front wall extending from the base and including an adapter panel supporting one or more fiber optic adapters, lateral housing sidewalls extending from the housing base and disposed at either side of the adapter panel, an opto-electrical device supported by the housing base, at least one optical fiber optically connecting the one or more fiber optic adapters to the opto-electronic device, and at least one cable manager supported on the housing base. The at least one cable manger includes a base, a plurality of cable routing channels disposed in the base, and at least one cable accumulation trough disposed along at least one of the plurality of cable routing channels. The at least one cable accumulation trough is configured to limit bending of the at least one optical to greater than a predetermined bend radius.
In some example embodiments, the at least one cable accumulation trough includes a plurality of cable accumulation troughs, and wherein at least some of the plurality of cable accumulation troughs comprise linear accumulation troughs disposed parallel or perpendicular to the lateral housing sidewalls. In an example embodiment, the at least one cable accumulation trough includes a plurality of cable accumulation troughs, and wherein at least some of the plurality of cable accumulation troughs comprise radial accumulation troughs extending outward from the opto-electrical device.
Additional embodiments, as shown with respect to
It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit or scope of the illustrated embodiments. Since modifications, combinations, sub-combinations and variations of the disclosed embodiments that incorporate the spirit and substance of the illustrated embodiments may occur to persons skilled in the art, the description should be construed to include everything within the scope of the appended claims and their equivalents.
This application is a continuation of International Patent Application No. PCT/US2022/046637 filed Oct. 14, 2022, which claims the benefit of priority to U.S. Provisional Application Nos. 63/397,634, filed Aug. 12, 2022, 63/287,585, filed Dec. 9, 2021, and 63/257,151, filed Oct. 19, 2021. The entirety of each forementioned priority application is incorporated herein by reference.
Number | Date | Country | |
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63397634 | Aug 2022 | US | |
63287585 | Dec 2021 | US | |
63257151 | Oct 2021 | US |
Number | Date | Country | |
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Parent | PCT/US2022/046637 | Oct 2022 | WO |
Child | 18638312 | US |