Fiber optic distribution network employing fiber optic distribution assemblies of the same type, and related devices, components, and methods

A fiber optic distribution assembly includes a plurality of fiber optic connectors, each having a plurality of ports arranged in the same predetermined port configuration. The predetermined port configuration has a plurality of port positions. Each of a group of N first optical fibers is optically connected to a first (e.g., input) fiber optic connector at port positions 1 through N of the predetermined port configuration, to support a group of N drop connections. A plurality of M second optical fibers is connected between ports (N+1) through (M+N) of the first fiber optic connector and ports 1 through M of a second (e.g., lateral) fiber optic connector. A plurality of P third optical fibers is connected between ports (M+N+1) through (M+N+P) of the first fiber optic connector and ports 1 through P of a third (e.g., distribution) fiber optic connector.

BACKGROUND

The disclosure generally relates to a fiber optic distribution network, and more particularly to a fiber optic distribution network employing fiber optic distribution assemblies of the same type, and related devices, components, and methods.

Optical fiber is increasingly being used for a variety of broadband applications including voice, video and data transmissions. As a result of the ever-increasing demand for broadband communications, telecommunication and cable media service providers and/or operators are expanding their fiber optic networks to increase their networks' capacity and reach to provide more services, applications and information to more proximate and distant subscribers. To facilitate this capacity and reach, the fiber optic networks must employ additional fiber optic cable, hardware and components resulting in increased installation time, cost and maintenance. This results in the fiber optic networks becoming more complex, requiring architectures that allow for the most efficient delivery of fiber optic service to the subscriber. These architectures typically employ fiber optic network devices, such as fiber optic connection terminals, for example, in branches of the fiber optic network. The fiber optic network devices act to optically interconnect the fiber optic cables of the branch, separate or combine optical fibers in multi-fiber cables, and/or split or couple optical signals, as may be necessary.

For example, a multi-fiber feeder cable from a central office or a transport cable from a head end may connect to multiple multi-fiber distribution cables. Each distribution cable then may extend to a designated geographic area, thereby providing the optical service to subscribers in that area. A fiber optic drop cable from the subscriber premises may connect to the distribution cable to establish optical connectivity between the service provider and the subscriber in a fiber to the premises (FTTP), fiber-to-the-home (FTTH), or other type of fiber optic network (generally described as FTTx). However, extending the drop cable from the subscriber premises all the way to the distribution cable may require a substantial length of drop cable resulting in extensive cost and installation time. Moreover, the cost and installation time would be increased and compounded if a separate connection to the distribution cable was needed for each drop cable. To reduce the attendant cost and timing, while still maintaining optical connectivity between the distribution cable and the drop cable, and, thereby, between the service provider and the subscriber, one or more intermediate optical connection points, between the distribution cable and the drop cable may be incorporated.

To incorporate the intermediate optical connection points, a branch of the fiber optic network off of the distribution cable is established. The branch may be established at a branching point on the distribution cable, such as at a mid-span access location. A fiber optic connection terminal may be used as the intermediate optical connection point and be centrally located to all of the subscribers being served by that branch. Therefore, the drop cables may extend from the subscriber premises and connect to ports on the fiber optic connection terminal instead of directly to the distribution cable. However, the fiber optic connection terminals typically are configured for and adapted to optically interconnect to the distribution cable only the drop cables that are connected to that particular fiber optic connection terminal. Thus, each fiber optic connection terminal has its own dedicated sub-branch, i.e., stub cable, to provide optically connectivity with the distribution cable at the mid-span access location.

In situations where there are many subscriber premises to be served by one mid-span access location, more than one fiber optic connection terminal in the branch from that one mid-span access location may be needed. This is particularly applicable where the subscriber premises are separated by appreciable distances, for example without limitation, in rural areas. In such case, given the above-mentioned configuration of the fiber optic connection terminals and due to the dedicated branch (stub) cable, a separate branch with associated branch cable may have to be extended from the mid-span access location to each fiber optic connection terminal.

Similar to the drop cable situation, the cost of the branch cable is generally charged on a per foot installed basis. Accordingly, installing separate branch cables from one mid-span access location to each fiber optic connection terminal may be excessively costly and time consuming. In addition, different types of branching arrangements may require several different types of fiber optic connection terminals, with different port mapping schemes being used by different fiber optic connection terminals in the same distribution network. This approach has the drawback of requiring extensive pre-planning to determine the components needed at each point in the branch, and also requires providing potentially complex instructions to an installer in the field. Accordingly, there is a need for a fiber optic distribution network that uses interchangeable fiber optic connection terminals throughout the network as the FTTP optical network extends toward the subscriber premises.

No admission is made that any reference cited herein constitutes prior art. Applicant expressly reserves the right to challenge the accuracy and pertinency of any cited documents.

SUMMARY

The disclosure generally relates to a fiber optic distribution network, and more particularly to a fiber optic distribution network employing fiber optic distribution assemblies of the same type, and related devices, components, and methods. According to one embodiment, a fiber optic distribution assembly includes a plurality of fiber optic connectors, each having a plurality of ports arranged in the same predetermined port configuration. The predetermined port configuration has a plurality of port positions. Each of a group of N first optical fibers is optically connected to a first (e.g., input) fiber optic connector at port positions 1 through N of the predetermined port configuration, to support a group of N drop connections. A plurality of M second optical fibers is connected between ports (N+1) through (M+N) of the first fiber optic connector and ports 1 through M of a second (e.g., lateral) fiber optic connector. This allows the first fiber optic connector to support a drop port in each of M additional fiber optic distribution assemblies connected in series via the respective first fiber optic connectors. A plurality of P third optical fibers is connected between ports (M+N+1) through (M+N+P) of the first fiber optic connector and ports 1 through P of a third (e.g., distribution) fiber optic connector. This allows the second fiber optic connector to support a drop port in each of P additional fiber optic distribution assemblies connected in series via the respective second fiber optic connectors.

This arrangement permits a distribution network to be assembled using one type of distribution assembly interconnected by one type of branch cable. By using the above port mapping arrangement, the second (e.g., lateral) multifiber port is configured such that a plurality of fiber optic connection distribution assemblies (e.g., terminals) of the same type can be serially connected via their lateral multifiber ports in a daisy chain arrangement. This port mapping arrangement also allows a plurality of the same type of fiber optic distribution assemblies to be serially connected via their respective third (e.g., distribution) multifiber ports in a daisy chain arrangement. In this manner, a fiber optic network can be designed with a branching array of fiber optic distribution assemblies of the same type, in which every individual fiber of a main distribution cable can be connected to a drop cable at a different fiber optic distribution assembly in the fiber optic network. As a result, the design complexity of the branch is reduced, reducing component and man-hour costs, as well as simplifying the process of installing the fiber optic connection terminals in the field.

One embodiment of the disclosure relates to a fiber optic distribution assembly. The fiber optic distribution assembly comprises a first fiber optic connector having a plurality of ports arranged in a predetermined port configuration having at least five port positions. The fiber optic distribution assembly further comprises a second fiber optic connector having a plurality of ports arranged in the predetermined port configuration. The fiber optic distribution assembly further comprises a third fiber optic connector having a plurality of ports arranged in the predetermined port configuration. The fiber optic distribution assembly further comprises a first optical fiber comprising N optical fibers, each first optical fiber comprising a first end optically coupled to the first fiber optic connector at one of port positions 1 through N of the predetermined port configuration. The fiber optic distribution assembly further comprises a plurality of second optical fibers comprising M optical fibers, wherein M is equal to at least (N+1). Each second optical fiber comprises a first end optically coupled to the first fiber optic connector at one of port positions (N+1) through (N+M) of the predetermined port configuration. Each second optical fiber further comprises a second end optically coupled to the second fiber optic connector at one of port positions 1 through M of the predetermined port configuration. The fiber optic distribution assembly further comprises a plurality of third optical fibers comprising P optical fibers, wherein P is equal to at least (N+1). Each third optical fiber comprises a first end optically coupled to the first fiber optic connector at one of port positions (N+M+1) through (N+M+P) of the predetermined port configuration. Each third optical fiber further comprises a second end optically coupled to the third fiber optic connector at one of port positions 1 through P of the predetermined port configuration.

An additional embodiment of the disclosure relates to a fiber optic distribution assembly. The fiber optic distribution assembly comprises an input fiber optic connector having a plurality of ports arranged in a predetermined port configuration having at least five port positions. The fiber optic distribution assembly further comprises a lateral fiber optic connector having a plurality of ports arranged in the predetermined port configuration. The fiber optic distribution assembly further comprises a distribution fiber optic connector having a plurality of ports arranged in the predetermined port configuration. The fiber optic distribution assembly further comprises a first optical fiber having a first end optically coupled to the input fiber optic connector at a first port position of the predetermined port configuration. The fiber optic distribution assembly further comprises a second optical fiber having a first end optically coupled to the input fiber optic connector at a second port position of the predetermined port configuration and a second end optically coupled to the lateral fiber optic connector at the first port position of the predetermined port configuration. The fiber optic distribution assembly further comprises a third optical fiber having a first end optically coupled to the input fiber optic connector at a third port position of the predetermined port configuration and a second end optically coupled to the lateral fiber optic connector at the second port position of the predetermined port configuration. The fiber optic distribution assembly further comprises a fourth optical fiber having a first end optically coupled to the input fiber optic connector at a fourth port position of the predetermined port configuration and a second end optically coupled to the distribution fiber optic connector at the first port position of the predetermined port configuration. The fiber optic distribution assembly further comprises a fifth optical fiber having a first end optically coupled to the input fiber optic connector at a fifth port position of the predetermined port configuration and a second end optically coupled to the distribution fiber optic connector at the second port position of the predetermined port configuration.

An additional embodiment of the disclosure relates to a method of assembling a fiber optic distribution assembly. The method comprises providing a first fiber optic connector having a plurality of ports arranged in a predetermined port configuration having at least five port positions. The method further comprises optically coupling a first end of each of N first optical fibers to one of port positions 1 through N of predetermined port configuration of the first fiber optic connector, wherein N is equal to one or more. The method further comprises optically coupling a first end of each of a plurality of M second optical fibers to one of port positions (N+1) through (N+M) of the predetermined port configuration of the first fiber optic connector, wherein M is equal to at least (N+1). The method further comprises optically coupling a first end of each of the plurality of P third optical fibers to one of port positions (N+M+1) through (N+M+P) of the predetermined port configuration of the first fiber optic connector, wherein P is equal to at least (N+1). The method further comprises providing a second fiber optic connector having a plurality of ports arranged in the predetermined port configuration. The method further comprises optically coupling a second end of each of the plurality of M second optical fibers to one of port positions 1 through M of the predetermined port configuration of the second fiber optic connector. The method further comprises providing a third fiber optic connector having a plurality of ports arranged in the predetermined port configuration. The method further comprises optically coupling a second end of each of the plurality of P third optical fibers to one of port positions 1 through P of the predetermined port configuration of the third fiber optic connector.

An additional embodiment of the disclosure relates a network system for a fiber optic distribution network. The network system comprises a plurality of fiber optic distribution assemblies. Each fiber optic distribution assembly comprises a first fiber optic connector having a plurality of ports arranged in a predetermined port configuration having at least five port positions. Each fiber optic distribution assembly further comprises a second fiber optic connector having a plurality of ports arranged in the predetermined port configuration. Each fiber optic distribution assembly further comprises a third fiber optic connector having a plurality of ports arranged in the predetermined port configuration. The plurality of fiber optic distribution assemblies comprises a first fiber optic distribution assembly optically coupled to a distribution cable via the first multifiber connector of the first fiber optic distribution assembly. The plurality of fiber optic distribution assemblies further comprises a second fiber optic distribution assembly optically coupled to the second multifiber connector of the first fiber optic distribution assembly via the first multifiber connector of the second fiber optic distribution assembly. The plurality of fiber optic distribution assemblies further comprises a third fiber optic distribution assembly optically coupled to the second multifiber connector of the second fiber optic distribution assembly via the first multifiber connector of the third fiber optic distribution assembly. The plurality of fiber optic distribution assemblies further comprises a fourth fiber optic distribution assembly optically coupled to the third multifiber connector of the first fiber optic distribution assembly via the first multifiber connector of the fourth fiber optic distribution assembly. The plurality of fiber optic distribution assemblies further comprises a fifth fiber optic distribution assembly optically coupled to the fourth multifiber connector of the first fiber optic distribution assembly via the first multifiber connector of the fifth fiber optic distribution assembly.

DETAILED DESCRIPTION

The disclosure generally relates to a fiber optic distribution network, and more particularly to a fiber optic distribution network employing fiber optic distribution assemblies of the same type, and related devices, components, and methods. According to one embodiment, a fiber optic distribution assembly includes a plurality of fiber optic connectors, each having a plurality of ports arranged in the same predetermined port configuration. The predetermined port configuration has a plurality of port positions. Each of a group of N first optical fibers is optically connected to a first (e.g., input) fiber optic connector at port positions 1 through N of the predetermined port configuration, to support a group of N drop connections. A plurality of M second optical fibers is connected between ports (N+1) through (M+N) of the first fiber optic connector and ports 1 through M of a second (e.g., lateral) fiber optic connector. This allows the first fiber optic connector to support a drop port in each of M additional fiber optic distribution assemblies connected in series via the respective first fiber optic connectors. A plurality of P third optical fibers is connected between ports (M+N+1) through (M+N+P) of the first fiber optic connector and ports 1 through P of a third (e.g., distribution) fiber optic connector. This allows the second fiber optic connector to support a drop port in each of P additional fiber optic distribution assemblies connected in series via the respective second fiber optic connectors.

This arrangement permits a distribution network to be assembled using one type of distribution assembly interconnected by one type of branch cable. By using the above port mapping arrangement, the second (e.g., lateral) multifiber port is configured such that a plurality of fiber optic connection distribution assemblies (e.g., terminals) of the same type can be serially connected via their lateral multifiber ports in a daisy chain arrangement. This port mapping arrangement also allows a plurality of the same type of fiber optic distribution assemblies to be serially connected via their respective third (e.g., distribution) multifiber ports in a daisy chain arrangement. In this manner, a fiber optic network can be designed with a branching array of fiber optic distribution assemblies of the same type, in which every individual fiber of a main distribution cable can be connected to a drop cable at a different fiber optic distribution assembly in the fiber optic network. As a result, the design complexity of the branch is reduced, reducing component and man-hour costs, as well as simplifying the process of installing the fiber optic connection terminals in the field.

Various embodiments will be further clarified by the following examples.

In this regard,FIG. 1illustrates a portion of a fiber optic network100employing fiber optic distribution assemblies (described in detail below) of the same type, according to an embodiment. The illustrated portion of the fiber optic network100may be at any point in the fiber optic network100, near to or distant from the central office or head end (not shown). The fiber optic network comprises a fiber optic distribution cable112, a mid-span access location114, and multiple fiber optic connection terminals118, only four of which are shown. The mid-span access location114provides a branch point for branch116. A plurality of fiber optic connection terminals118are interconnected via a plurality of branch cables120, which are connected, directly or indirectly, to the fiber optic distribution cable112through a network connector122. One or more drop cables124may extend from the housing126of one or more fiber optic connection terminals118. In this embodiment, each housing126includes a branch cable opening128, which may also be referred to herein as a branch cable port, for receiving an upstream branch cable120, and one or more drop ports130. In this embodiment drop cables124may extend from the drop ports130to provide service to one or more subscriber premises132. In this manner, branch cable120provides optical communication between the fiber optic distribution cable112and the subscriber premises132through the fiber optic connection terminals118.

In this embodiment, the housing126of each fiber optic connection terminal118further includes a lateral multifiber port134and an expansion multifiber port136for connecting additional fiber optic connection terminals118to the branch116. The lateral multifiber port134is configured such that a plurality of fiber optic connection terminals118of the same type can be connected in a daisy chain arrangement, and the expansion multifiber port136is also configured such that a plurality of the same type of fiber optic connection terminals118can be connected in a daisy chain arrangement.

In this manner, a fiber optic network100can be designed such that every individual fiber of the fiber optic distribution cable112can be connected to a drop cable124at a different fiber optic connection terminal118, using only one type of fiber optic connection terminal118. By using a branching array of fiber optic distribution assemblies118of the same type, the design complexity of the branch116is reduced, thereby reducing component and man-hour costs, as well as simplifying the process of installing the fiber optic connection terminals118in the field.

With continuing reference toFIG. 1, each branch cable120comprises optical fibers designated by the letter “F.” In this example, each branch cable120has twelve optical fibers F1-F12, but it should be understood that any branch cables120having more or fewer optical fibers may also be used. A segment of the branch cable120is shown extending from the fiber optic distribution cable112at mid-span access location114to a fiber optic connection terminal118(1A).

The fiber optic connection terminals118are each configured with a common port mapping scheme. The port mapping scheme predetermines the routing and optical coupling of the optical fibers in the branch cable120via the drop port130, the lateral multifiber port134, the expansion multifiber port136, another component, another connector (not shown), and/or the like in the fiber optic connection terminal118. The port mapping scheme of the fiber optic connection terminals118serves to predetermine the routing and optical coupling of optical fibers F1-F12for each of the fiber optic connection terminals118. In other words, the port mapping scheme predetermines the routing and optical coupling not only of the fiber optic distribution cable112and the drop cable124extending from the drop port130of the first fiber optic connection terminal118, but also of the fiber optic distribution cable112and the drop cable124extending from the drop port130of the other fiber optic connection terminals118in the branch116. The port mapping scheme also predetermines the optical coupling of the fiber optic distribution cable112and the drop cable124extending from the drop port130of the second fiber optic connection terminal118through the lateral multifiber port134and the expansion multifiber port136of each fiber optic connection terminal118. Further, a branch cable120comprising optical fibers F1-F12may extend from either of the lateral multifiber port134or the expansion multifiber port136to another successive downstream fiber optic connection terminal118in the branch116. In this manner, the port mapping scheme predetermines the optical coupling between the fiber optic distribution cable112and the drop ports130of the fiber optic connection terminals118in the branch116.

In this embodiment, the port mapping scheme of the fiber optic connection terminal118(1A) routes optical fiber F1to a drop port130, to provide service to one or more subscriber premises132. Optical fibers F2and F3are routed to the lateral multifiber port134, and are connected with optical fibers F1and F2of a lateral branch cable138of the next fiber optic connection terminal118(1B) in the lateral-side chain. Optical fibers F4-F12of the fiber optic connection terminal118(1A) are routed to the expansion multifiber port136, and are connected to optical fibers F2-F9of an expansion branch cable140of the next fiber optic connection terminal118(2A) in the distribution-side chain.

Referring now to the lateral-side chain extending from fiber optic connection terminal118(1A), the next fiber optic connection terminal118(1B) in the chain has the same port mapping scheme as fiber optic connection terminal118(1A), and may be a standardized component that is interchangeable with fiber optic connection terminal118(1A). The lateral branch cable138extends from the lateral multifiber port134of the fiber optic connection terminal118(1A) into the downstream fiber optic connection terminal118(1B) via the branch cable opening128. Fibers F1-F12of the lateral branch cable are arranged in a port mapping scheme in the fiber optic connection terminal118(1B) that is identical to the mapping scheme in the fiber optic connection terminal118(1B). That is, optical fiber F1is connected to a drop port130, optical fibers F2and F3are connected to the lateral multifiber port134, and optical fibers F4-F12are connected to the expansion multifiber port136. Here, however, optical fibers F1and F2of the fiber optic connection terminal118(1B) are the only fibers that are connected back to the fiber optic distribution cable112, i.e., optical fibers F2and F3of the fiber optic distribution cable112. The remaining fibers F3-F12in the fiber optic connection terminal118(1B) are “dead.” Thus, as additional fiber optic connection terminals118are added to each lateral-side chain in this embodiment, the first fiber F1in each fiber optic connection terminal118is connected to a drop port130, and the remaining number of “live” fibers is reduced by one.

Referring now to the distribution-side chain extending from fiber optic connection terminal118(1A), the next fiber optic connection terminal118(2A) in the chain also has the same port mapping scheme as fiber optic connection terminal118(1A), similar to lateral-side fiber optic connection terminal118(1B). The lateral branch cable138extends from the expansion multifiber port136of the fiber optic connection terminal118(1A) into the downstream fiber optic connection terminal118(2A) via the branch cable opening128. Optical fibers F1-F12of the lateral branch cable are arranged in a port mapping scheme in the fiber optic connection terminal118(2A) that is identical to the mapping scheme in the fiber optic connection terminal118(1B). That is, optical fiber F1is connected to a drop port130, optical fibers F2and F3are connected to the lateral multifiber port134, and optical fibers F4-F12are connected to the expansion multifiber port136. Here, fibers F1-F9of the fiber optic connection terminal118(1B) are the only fibers that are connected back to the fiber optic distribution cable112, i.e., optical fibers F4-F12of the distribution cable. The remaining fibers F10-F12in the fiber optic connection terminal118(1B) are “dead.” However, this still results in live optical fibers being available at both the lateral multifiber port134and the expansion multifiber port136of the fiber optic connection terminal118(2A). This allows another fiber optic connection terminal118(2B) to be connected to the lateral multifiber port134of the fiber optic connection terminal118(2A) to provide another lateral-side chain, and also allows another fiber optic connection terminal118(not shown) to be connected to the expansion multifiber port136of the fiber optic connection terminal118(2A) to continue the distribution-side chain. As additional fiber optic connection terminals118are added to the distribution-side chain in this embodiment, the first fiber F1in each fiber optic connection terminal118is connected to a drop port130, the next two optical fibers F2and F3are connected to the lateral multifiber port, and the remaining number of “live” optical fibers available for connection to another fiber optic connection terminal in the distribution-side chain is reduced by three.

It should be understood the embodiment ofFIG. 1may be modified so that different port mapping schemes may also employ a different number of optical fibers connected to one or more drop ports130, a different number of optical fibers connected to the lateral multifiber port134, and/or a different number of optical fibers connected to the expansion multifiber port136. In the above example, a distribution cable with twelve live optical fibers can provide a signal to the drop port130of up to four fiber optic connection terminals118connected in a distribution-side chain, with each fiber optic connection terminal118in the distribution-side chain providing a signal to each drop port130in up to two additional fiber optic connection terminals118in a lateral-side chain connected to the respective fiber optic connection terminal118in the distribution-side chain. In general, to provide at least one live signal to multiple fiber optic connection terminals118in a lateral-side chain and at least one fiber optic connection terminal118in an expansion-side chain simultaneously, the number (M) of optical fibers used by the lateral multifiber port134must exceed the number (N) of optical fibers connected to a drop port130in the fiber optic connection terminal118, and the number (P) of optical fibers used by the expansion multifiber port136in the fiber optic connection terminal118must also exceed N. Thus, in this example, if N is 1, M must be 2 or more, and P must also be 2 or more. To provide at least one live signal to multiple fiber optic connection terminals118in a lateral-side chain and at least one fiber optic connection terminal118in an expansion-side chain simultaneously, M must exceed N, and P must exceed the sum of N and M. Thus, in this example, if N is 1, M must be 2 or more, and P must be 4 or more.

The fiber optic connection terminal118may also include additional optical components including, but not limited to a splitter, splice protector, WDM device, splice holder and tray, routing guide and slack storage. The port mapping scheme may predetermine the configuring of the fiber optic connection terminal with one or more of these other optical components, and/or the routing of optical fibers to and optically coupling of optical fibers with one or more of the components. As an example, an optical fiber from the branch cable120may optically couple to a splitter. The optical signal carried by that optical fiber may be split into multiple optical signals by the splitter. In one example, the optical fiber F1may output from the splitter and route to one or more drop ports130in the fiber optic connection terminal118.

Referring now toFIG. 2, a more detailed schematic diagram of the fiber optic connection terminal218ofFIG. 1is illustrated with additional components thereof for additional exemplary discussion. In this example, the fiber optic connection terminal218has four drop ports230disposed in the housing226. Each drop port230may include a fiber optic adapter244, which may be a single fiber adapter or a multifiber adapter.

In this example, the lateral multifiber port234comprises a lateral multifiber adapter246, and the expansion multifiber port236also comprises an expansion multifiber adapter248of the same type. In this embodiment, the branch cable opening228is an input multifiber port having an input multifiber adapter250, but it should be understood that the branch cable opening228may alternatively be a pass-through opening for the branch cable220. The lateral multifiber adapter246is disposed in the lateral multifiber port234and an expansion multifiber adapter248of the same type is disposed in the expansion multifiber port236. In this example, an input multifiber adapter250is also disposed in the input port, i.e., the branch cable opening228.

In this embodiment, each fiber optic adapter244is configured to optically couple a pair of multifiber connectors252to each other. In this embodiment, a splitter254, which is a 1×4 splitter in this embodiment, is optically coupled to optical fiber F1, and outputs multiple output signals to the drop ports230via optical fibers F1-1, F1-2, F1-3, and F1-4. Each of the optical fibers F1-1, F1-2, F1-3, and F1-4is terminated with multifiber connector252, and is optically coupled to a complementary fiber optic adapter244connected to a respective drop cable224.

Referring now to the lateral multifiber port234, the lateral multifiber adapter246is configured to optically couple a pair of multifiber connectors256. Each multifiber connector256has a plurality of ports arranged in a predetermined port configuration having twelve port positions P1-P12. It should be understood that other port configurations having a different number of ports may be used, with different limitations based on the desired layout of the network. For example, in order to provide at least one live signal to multiple fiber optic connection terminals218in a lateral-side chain and at least one fiber optic connection terminal218in an expansion-side chain simultaneously, the minimum number of port positions is five. This is because the number (M) of optical fibers used by the lateral multifiber port234must exceed the number (N) of optical fibers connected to a drop port230in the fiber optic connection terminal218, and the number (P) of optical fibers used by the expansion multifiber port236in the fiber optic connection terminal218must also exceed N. Since the minimum number of port positions is the sum of N, M, and P, and both M and P must be at least two, the minimum number of port positions for this arrangement is five. Similarly, in order to provide at least one live signal to multiple fiber optic connection terminals218in a lateral-side chain and at least one fiber optic connection terminal218in an expansion-side chain simultaneously, M must exceed N, and P must exceed the sum of N and M. Thus, because, M must be at least two, and P must be at least four, the sum of N, M, and P must be at least seven.

Referring back to the example ofFIG. 2, a lateral multifiber connector258, which is one of the multifiber connectors252, connects optical fibers F2and F3at port positions P1and P2. Similarly, the expansion multifiber adapter248is configured to optically couple another pair of multifiber connectors256, each having a plurality of ports arranged in the same predetermined port configuration having twelve port positions P1-P12. An expansion multifiber connector260, which is one of the multifiber connectors252, connects optical fibers F4-F9at port positions P1-P9. In this embodiment as well, the input multifiber adapter250may also be configured to optically couple a pair of multifiber connectors252, each having the same port configuration. An input multifiber connector262, which is one of the multifiber connectors252, connects optical fibers F1-F12at port positions P1-P12to act as a passthrough port for the multifiber connector256optically coupled to the branch cable220.

As used herein and well known and understood in the art, the term “drop cable” shall mean and include a fiber optic cable from a subscriber premises. Also, the term “distribution cable” shall mean and include any one or more of fiber optic cables in the form of a feeder cable from a central office of a telecommunications service provider or operator, a transport cable from a head end of a cable media service provider or operator, as well as a fiber optic cable that may be optically connected to a feeder cable or a transport cable and used to further distribute the optical services toward a subscriber premises. The term “branch cable” shall mean and include any fiber optic cable, including but not limited to, a tether cable and/or a stub cable, as those terms are known in the art, and any other cable that may optically connect to and/or extend from a distribution cable for the purpose of optically connecting the distribution cable to a drop cable. The distribution cable, branch cable and/or drop cable may be any type of fiber optic cable having one or more optical fibers. The term “optical fiber” is intended to include all types of single mode and multi-mode light waveguides, including one or more bare optical fibers, loose-tube optical fibers, tight-buffered optical fibers, ribbonized optical fibers, bend insensitive optical fibers, or any other expedient of a medium for transmitting light signals.

The drop cable may be “pre-connectorized” to be readily connected to and disconnected from a drop port of the fiber optic connection terminal. At the other end, the drop cable may be optically coupled to optical fibers within a conventional closure, such as, but not limited to, a network interface device (NID) of the types available from Corning Cable Systems LLC of Hickory, N.C. In the exemplary embodiments shown and described herein, the drop cables extend from a closure located at a subscriber premises and are optically coupled through the drop ports of the fiber optic connection terminal to one or more optical fibers of a branch cable. In turn, the optical fibers of the branch cable are optically coupled to optical fibers of the distribution cable, at a mid-span access location on the distribution cable. The mid-span access location may be provided at an aerial closure, a buried closure (also referred to as a below grade closure) or an above-ground telecommunications cabinet, terminal, pedestal, or the like. Likewise, the fiber optic connection terminal may be provided at an aerial location, such as mounted to an aerial strand between utility poles or mounted on a utility pole, at a buried location, such as within a hand-hole or below grade vault, or at an above-ground location, such as within a cabinet, terminal, pedestal, above grade vault, or the like. Thus, the fiber optic connection terminal provides an accessible interconnection terminal for readily connecting, disconnecting or reconfiguring drop cables in the optical network, and in particular, for optically coupling drop cables with a distribution cable. The terms connect, interconnect, and couple shall be understood to mean, without limitation, the passage, flow, transmission, or the like of an optical signal between one or more of optical cables, optical fibers, components, and/or connectors, or the like and one or more of optical cables, optical fibers, components, and/or connectors, or the like; whether or not by direct or indirect physical connection, to establish optical communication or connectivity.

In some embodiments, a fiber optic adapter may be a hardened fiber optic adapter for connecting a hardened fiber optic connector for a distribution or branch cable, for example. As used herein, the term “hardened” in relation to a fiber optic adapter and/or fiber optic connector refers to environmentally resistant fiber optic adapters and fiber optic connectors that are configured for use in an outdoor (e.g., OSP) environment, such as, for example, Corning Optical Communications′® OptiTap®, OptiTip®, and FlexNAP™ connectivity solutions.

A branching point may be established at a mid-span access location and/or at the end of a distribution cable. For purposes herein, reference to mid-span access location shall be understood to also include the end of the distribution cable. The direction in the branch cable toward or facing the mid-span access location may be referred to as “upstream” and the direction facing away from the mid-span access location may be referred to as “downstream.” It should be understood, though, that using the terms “upstream” or “downstream” does not indicate the direction in which the optical signals are transmitted or carried in the optical fibers. Thus, an optical signal may be transmitted in both the upstream or downstream direction.

Due to the port mapping scheme, more than one fiber optic connection terminal may be directly or indirectly connected in the branch. Because more than one fiber optic connection terminal may be included in the branch, distributed, and/or hierarchical architectures, including embodiments disclosed herein, may be employed to position the fiber optic connection terminals at more convenient locations with respect to the subscriber premises. As a result, drop cables extending from a subscriber premises may be optically coupled to the fiber optic network at a fiber optic connection terminal more closely located to the subscriber premises as opposed to a fiber optic connection terminal located more distantly or at the actual mid-span access location provided on the distribution cable. Thus, the overall length of the drop cables may be substantially reduced, and a greater number of subscriber premises may be serviced over a wider area.

Referring back toFIG. 2, the lateral multifiber connector258and the expansion multifiber connector260have the same port configuration and are thus both configured to be optically coupled with a branch multifiber connector264coupled to another downstream fiber optic connection terminal218of the same type. In this regard,FIG. 3Aillustrates a portion of a branch316of a network, similar to the fiber optic network100ofFIG. 1, comprising a plurality of fiber optic connection terminals318(1A)-318(4A) connected to a fiber optic distribution cable312in a distribution-side chain. In this embodiment, fiber optic connection terminal318(A1) is connected to the fiber optic distribution cable312via branch cable320extending between the fiber optic connection terminal318(1A) and a mid-span access location314. In this embodiment (and in the embodiments of subsequentFIGS. 3B-4), the port mapping scheme of each of the fiber optic connection terminals318is the port mapping scheme illustrated inFIG. 2.

In this regard, fiber optic connection terminal318(1A) receives optical fibers F1-F12from branch cable320at the branch cable opening328. Optical fiber F1is split by the splitter354into a plurality of optical fibers connected to the plurality of drop ports330. Optical fibers F2and F3are connected to ports P1and P2of lateral multifiber connector (not shown) at the lateral multifiber port334(1A), which is in turn connected to lateral branch cable338(1B) of fiber optic connection terminal318(1B) in the lateral-side chain. The remaining nine optical fibers F4-F12are connected to the expansion multifiber connector (not shown) at the expansion multifiber port336(1A).

The next fiber optic connection terminal318(2A) in the distribution-side chain is connected to the fiber optic connection terminal318(1A) via expansion branch cable340(2A). Optical fiber F1is split by the splitter354into a plurality of optical fibers connected to the plurality of drop ports330, and optical fibers F2and F3are connected to ports P1and P2of the lateral multifiber connector58at the lateral multifiber port334(2A). Live optical fibers F4-F9are connected to ports P1-P6of the expansion multifiber connector60at the expansion multifiber port336(2A), and dead optical fibers F10-F12are connected to ports P7-P9.

In this manner, each fiber optic connection terminal318(1A)-318(4A) of the distribution-side chain routes optical fibers F1-F3away from the respective expansion multifiber port336, and reroutes the remaining optical fibers to port positions P1-PX of the expansion multifiber port336. Thus, for a distribution cable with twelve optical fibers the maximum number of fiber optic connection terminals318in a distribution-side chain having this port mapping configuration is four, because each successive expansion multifiber port336has three fewer live optical fibers.

Referring now toFIG. 3B, a portion of the branch316is illustrated comprising a plurality of fiber optic connection terminals318(1A)-318(1C) connected to a fiber optic distribution cable312in a lateral-side chain. As discussed above, each fiber optic connection terminal318(1A)-18(1C) of the lateral-side chain routes optical fibers F1and F4-F12away from the respective lateral multifiber port334(1A)-334(1C), and reroutes the remaining optical fibers to port positions P1-PX of the expansion multifiber port336(1A)-336(1C). Thus, for a distribution cable with twelve optical fibers the maximum number of fiber optic connection terminals318in a distribution-side chain having this port mapping configuration is three, because the second lateral multifiber port334(1B) in the lateral-side chain has all but one live optical fiber (F2) routed away from the lateral multifiber port334(1B). Live optical fiber F2is routed to port P1of the lateral multifiber port334(1B), and is then routed to the drop ports330in the third fiber optic connection terminal318(1C) in the lateral-side chain.

Referring now toFIG. 3C, the complete branch316is illustrated. The branch316has four fiber optic connection terminals318(1A)-318(4A) connected in an expansion-side chain, with each fiber optic connection terminal318in the expansion-side chain providing a signal to each drop port330in up to two additional fiber optic connection terminals318in a respective lateral-side chain. Each lateral-side chain is connected to the respective fiber optic connection terminal318in the distribution-side chain. In this regard, fiber optic connection terminal318(1A) is connected to fiber optic connection terminals318(1B) and fiber optic connection terminals318(1C) in a lateral-side chain, and fiber optic connection terminal318(2A) is connected to fiber optic connection terminals318(2B) and fiber optic connection terminals318(2C) in a lateral-side chain. Fiber optic connection terminal318(3A) is connected to fiber optic connection terminals318(3B) and fiber optic connection terminals318(3C) in a lateral-side chain, and fiber optic connection terminal318(4A) is connected to fiber optic connection terminals318(4B) and fiber optic connection terminals318(4C) in a lateral-side chain.

Referring now toFIG. 4, a schematic view of a larger portion of the network400illustrating two fully built-out branches416along the main fiber optic distribution cable412. In this example, each branch416supports forty-eight separate subscriber premises from a single mid-span access location414. In this manner, the network400can be efficiently scaled out in stages, and in a more cost-effective manner.

FIG. 5is a flowchart of a method500of assembling a fiber optic distribution, such as the fiber optic connection terminal118,218,318ofFIGS. 1-4, for example, according to an embodiment. The method500comprises providing a first fiber optic connector, such as the input multifiber connector262or other multifiber connector256ofFIG. 2, for example, having a plurality of ports arranged in a predetermined port configuration having at least five port positions (Block502), and optically coupling a first end of each of N first optical fibers to one of port positions P1through PN of the predetermined port configuration of the first fiber optic connector, wherein N is equal to one or more (Block504). The method500further comprises optically coupling a first end of each of a plurality of M second optical fibers to one of port positions (N+1) through (N+M) of the predetermined port configuration of the first fiber optic connector, wherein M is equal to at least (N+1) (Block506), and optically coupling a first end of each of the plurality of P third optical fibers to one of port positions (N+M+1) through (N+M+P) of the predetermined port configuration of the first fiber optic connector, wherein P is equal to at least (N+1) (Block508). The method500further comprises providing a second fiber optic connector, such as the lateral multifiber connector258ofFIG. 2, for example, having a plurality of ports arranged in the predetermined port configuration (Block510), and optically coupling a second end of each of the plurality of M second optical fibers to one of port positions P1through PM of the predetermined port configuration of the second fiber optic connector (Block512). The method further comprises providing a third fiber optic connector, such as the expansion multifiber connector260ofFIG. 2, for example, having a plurality of ports arranged in the predetermined port configuration (Block514), and optically coupling a second end of each of the plurality of P third optical fibers to one of port positions P1through PP of the predetermined port configuration of the third fiber optic connector (Block516).

The fiber optic connection terminal118,218,318, as well as any other fiber optic distribution assemblies disclosed herein, may be any type of fiber optic network device and, therefore, may have any structure. Accordingly, without limiting in any manner the type or structure of fiber optic network device in which the present invention may be practiced, an exemplary embodiment of a fiber optic network device in the form of a multi-port device will now be described with reference toFIGS. 6-8.

Turning now toFIGS. 6 and 7, an exemplary embodiment of a multi-port device as a fiber optic connection terminal618in accordance with the present invention is shown. As shown inFIG. 6, the fiber optic connection terminal618comprises a base670and a cover672each made of a lightweight, yet rigid material, such as plastic, thermoplastic, composite or aluminum material. The base670and the cover672define an enclosure having an exterior surface. Additionally, the base670has opposed end walls674,676and sidewalls678,680, of the exterior surface. The base670is further provided with an upper surface682of the exterior surface. The upper surface682of the base670is provided with a plurality of angled or sloped surfaces684. In this embodiment, each angled surface684has at least one drop port630, at least one lateral multifiber port634, and at least one expansion multifiber port636formed therethrough. Further, the base670is generally box-shaped and defines an interior cavity686for housing fiber optic hardware, such as connector ports, adapters, optical fiber routing guides, fiber hubs and the like. The base670may have any of a variety of shapes that is suitable for housing fiber optic hardware and for routing and connecting optical fibers of the branch cable620, as described herein. However, by way of example only, the base670of this embodiment is generally rectangular and is elongated in the lengthwise direction relative to the widthwise direction between the opposed end walls674,676.

A branch cable opening628is disposed through the exterior surface. Although the branch cable opening628may be at any position through the exterior surface, in the embodiment shown, the branch cable opening628is disposed in the end wall674of the base670. The branch cable opening628is operable for receiving a branch cable assembly688comprising the branch cable620. The branch cable assembly688is inserted through the branch cable opening628of the fiber optic connection terminal618. The end of the branch cable620having at least one pre-connectorized optical fiber mounted thereon is routed through the branch cable opening628into the interior cavity686. The branch cable assembly688is any type of assembly or structure that provides for the entrance of the branch cable620into the fiber optic connection terminal618, and the sealing of the branch cable620as it enters the fiber optic connection terminal618. Additionally, the branch cable assembly688may provide strain relief to the branch cable620as is known in the art. Alternatively, a multi-fiber connector (not shown) may be used to connect the branch cable620to the fiber optic connection terminal618. In such case, instead of the branch cable assembly688as depicted inFIGS. 6 and 7, the multi-fiber connector may be connected to an adapter seated within the branch cable opening628. Another multi-fiber connector (not shown) may be used to connect to the adapter in the interior cavity686, thereby optically connecting the optical fibers of the branch cable620to optical fibers disposed within the fiber optic connection terminal618.

The cover672is adapted to be attached to the base670such that the fiber optic connection terminal618is re-enterable to provide ready access to the interior cavity686, particularly in the field, if necessary to reconfigure the optical fibers of the branch cable620relative to the drop ports630, the lateral multifiber port634, and the expansion multifiber port636. Specifically, the base670and cover672are preferably provided with a fastening mechanism690such as, but not limited to, clasps, fasteners, threaded bolts or screws and inserts, or other conventional means for securing the cover672to the base670in the closed configuration. However, the cover672may be slidably attached to the base670to selectively expose portions of the interior cavity686of the base670(not shown). Alternatively, the cover672may be hingedly attached to the base670at one or more hinge locations (not shown) to allow the cover672and base670to remain secured to one another in the opened configuration. A gasket692may be disposed between a peripheral flange provided on the base670and the interior of the cover672. As shown, the gasket692is generally rectangular and of a size corresponding to that of the base670and the cover672. Alternatively, in certain locations the service provider may determine that it is not desirable that fiber optic connection terminal618be enterable in the field, and, therefore, may decide to fasten the base670to the cover672by welding, for example using an epoxy type of weld.

As illustrated inFIG. 7, the branch cable620passes through the branch cable opening628and enters the fiber optic connection terminal618. A securing mechanism694, such as for example, a fastener, clamp and nut, bracket or clasp, is provided in the interior cavity686of the fiber optic connection terminal618to secure the branch cable620to the base670. Alternatively, instead of the branch cable620passing through the branch cable opening628, the branch cable620may have a connector on the end, which, in such case, would connect with an adapter seated in the branch cable opening628. Also, alternatively, the optical fibers in the branch cable620may be spliced, for example, fusion spliced, with optical fibers in the interior cavity686. In this embodiment, the branch cable620is a twelve fiber optical cable. It should be understood that the present invention is not limited to a branch cable620having any specific number of optical fibers. A branch cable620having less or more than twelve optical fibers may be used. Within the fiber optic connection terminal618, at least one individual optical fiber of the branch cable620in the form of a pigtail terminates at its respective connector. The pre-connectorized optical fiber or pigtail is routed within the interior cavity686of the fiber optic connection terminal618and connects to an adapter (not shown) seated within the respective drop port630. The optical fiber or pigtail may be pre-connectorized with any suitable connector, for example, an SC connector available from Corning Optical Communications LLC of Hickory, N.C. InFIG. 7, four pre-connectorized optical fibers are shown each connecting to the respective drop port630. A field-connectorized or pre-connectorized drop cable624may be connected to the adapter seated within the drop port630from the exterior of the fiber optic connection terminal618. The drop cable624may be connectorized or pre-connectorized with any suitable ruggedized connector, for example, an OptiTap® or OptiTip® connector available from Corning Optical Communications LLC of Hickory, N.C.

Additionally, optical fibers of the branch cable620may be connected to a pass-through connector, such as a lateral multifiber connector (not shown) disposed in the lateral multifiber port634, or an expansion multifiber connector (not shown) disposed in the expansion multifiber port636. The pass-through connector may be any type of multi-fiber connector, such as an MTP connector available from Corning Optical Communications LLC of Hickory, N.C. Alternatively, a splice, such as a fusion splice may be used instead of a pass-through connector. In this embodiment, optical fibers of the branch cable620are connected to the pass-through connectors as described in detail above. The pass-through connectors connect to multi-fiber adapters (not shown) seated in the lateral multifiber port634and the expansion multifiber port636. A lateral branch cable638and an expansion branch cable640each extend to another fiber optic connection terminal618, each connecting back to a network connector622external to branch616of fiber optic connection terminals618. As described above, the network connector622may be any type of multi-fiber connector, such as an OptiTip® fiber optic connector. Thus, the multi-fiber adapter (not shown) may be an MTP/OptiTip® adapter to accept and connect the branch connector (not shown), an MTP connector, and the network connector622, an OptiTip® connector. In this manner, the fiber optic connection terminal618may be series and/or sub-branch connected with another fiber optic connection terminal618. In this manner, optical coupling according to a port mapping scheme may be established between certain of the optical fibers of the branch cable620in the interior cavity686and to the branch cable120that extends between fiber optic connection terminals.

InFIG. 8, another exemplary embodiment of a structure of a fiber optic connection terminal in accordance with the present invention is shown. In this embodiment, the fiber optic connection terminal818is similar to the fiber optic connection terminal618depicted inFIGS. 6 and 7, and, therefore, like components will not be discussed again with reference toFIG. 8. The fiber optic connection terminal818inFIG. 8includes a splitter854. Although only one splitter854is shown in this embodiment, it should be understood that the invention is not limited to one splitter854and multiple splitters854may be included. The splitter854may be mounted on a shelf896having at least one cutout898. One or more fastening mechanisms890(not shown) may be used to affix the splitter854to the base870using the fastening mechanisms890.

In this embodiment, the splitter854may be a 1×4 splitter in that one optical signal input to the splitter854may be split into four optical signals output from the splitter854. It should be noted that since the optical signals may travel in both directions, the operation of the splitter854may be viewed from the reverse optical signal direction, in which case four optical signals input to the splitter854will be coupled into one optical signal output from the splitter854. One optical fiber indicated inFIG. 8as F1from the twelve fiber branch cable820routes to and optically couples with the splitter854, and the other optical fibers of the branch cable820route to the lateral multifiber port, similar to the lateral multifiber port634ofFIGS. 6 and 7, and the expansion multifiber port836, as described in detail above. Four first split optical fibers indicated inFIG. 8as F1-1, F1-2, F1-3, and F1-4are output from the splitter854. Each of the first split optical fibers output from the splitter854may be pre-connectorized and routed to one or more drop ports830. Further, as discussed above, more than one splitter854may be included in the fiber optic connection terminal818, in which case, the optical fibers may route between the splitters854and the drop ports830, lateral multifiber port(s)834and/or distribution multifiber port(s)836according to the port mapping scheme employed.